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Chapter 4
Table of Contents Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems General .................................................................................................................1 Introduction ......................................................................................................................................... 1 Design Considerations ................................................................................................................... 4 Horizontal Cable and Connecting Hardware ...............................5 Introduction ......................................................................................................................................... 5 Design Considerations ................................................................................................................... 6 Cable Lengths ...................................................................................................................................... 7 Topology ................................................................................................................................................. 9 Consolidation and Transition Points ...................................................................................10 Horizontal Cabling Schematic ................................................................................................11 Cable Slack ..........................................................................................................................................13 Grounding and Bonding Considerations .........................................................................14 Electromagnetic Interference (EMI) ....................................................................................16 Administration ..................................................................................................................................17 Crossovers ............................................................................................................................................18 Help Main TOC Print Search Search Find Find Quit Horizontal Cable ......................................................................................... 19 Cable Types .........................................................................................................................................19 Horizontal Media Selection ......................................................................................................20 Hybrid Cables ....................................................................................................................................22 i Table of Contents Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Horizontal Connecting Hardware..................................................... 24 General...................................................................................................................................................24 Equipment Connections .............................................................................................................24 Telecommunications Outlets ...................................................................................................25 Cabling Adapters .............................................................................................................................26 Open Office Cabling Systems..................................................................................................27 Multi-user Telecommunications Outlet Assembly .....................................................28 Consolidation Point (CP) ............................................................................................................31 Locating Multi-user Telecommunications Outlet Assemblies and Consolidation Points...............................................................................................................33 100-ohm UTP Cable Outlets .....................................................................................................37 100-ohm UTP Performance Categories .............................................................................41 Category Selection.........................................................................................................................44 62.5/125 µm Optical Fiber.........................................................................................................45 150-ohm STP-A Cable Outlet...................................................................................................47 Help Main TOC Print Search Search Find Find Quit Cross-connect Jumpers and Patch Cords .................................... 49 General...................................................................................................................................................49 Length Requirements ...................................................................................................................50 ii Table of Contents Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Cabling Practices ........................................................................................ 51 General...................................................................................................................................................51 Cable Management Practices ..................................................................................................51 Connector Termination Practices .........................................................................................55 Work Area Cables........................................................................................ 58 General...................................................................................................................................................58 Work Area Cables/Cords .............................................................................................................59 Cabling Links and Cabling Channels.............................................. 60 Introduction .......................................................................................................................................60 Cabling Links......................................................................................................................................61 Cabling Channels ............................................................................................................................64 Verification Testing ........................................................................................................................66 Help Main TOC Print Search Search Find Find Quit iii Table of Contents Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Horizontal Pathways and Spaces ...................................................... 67 Introduction .......................................................................................................................................67 Design Considerations .................................................................................................................69 Electromagnetic Interference (EMI) ....................................................................................70 Grounding and Bonding .............................................................................................................71 Firestopping .......................................................................................................................................72 Wet Locations ....................................................................................................................................72 Hazardous Locations .....................................................................................................................72 Administration ..................................................................................................................................73 Types of Horizontal Pathways .................................................................................................74 Advantages/Disadvantages of Various Distribution Systems ........................................................................................................ 75 Underfloor and Cellular System Advantages ................................................................75 Underfloor and Cellular System Disadvantages .........................................................76 Trench Duct Advantages ............................................................................................................77 Trench Duct Disadvantages......................................................................................................77 Advantages of Conduit Systems............................................................................................79 Disadvantages of Conduit Systems .....................................................................................79 Access Floor Advantages............................................................................................................80 Access Floor Disadvantages .....................................................................................................81 Help Main TOC Print Search Search Find Find Quit iv Table of Contents Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Ceiling System Advantages ......................................................................................................82 Ceiling System Disadvantages................................................................................................83 Advantages of Undercarpet Telecommunications Cable (UTC) ........................85 Disadvantages of Undercarpet Telecommunications Cable (UTC) ..................86 Poke-thru Disadvantages ...........................................................................................................87 Sizing of Horizontal Pathways............................................................ 89 Introduction .......................................................................................................................................89 Usable Floor Space .........................................................................................................................89 Occupant Density ...........................................................................................................................90 Cable Density.....................................................................................................................................90 Cable Diameter .................................................................................................................................91 Conduit Capacity .............................................................................................................................92 Determining Conduit Size .........................................................................................................95 Determining Raceway Size........................................................................................................97 Determining Duct Size ................................................................................................................97 Help Main TOC Print Search Search Find Find Quit v Table of Contents Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Underfloor Duct Systems ...................................................................... 98 Introduction .......................................................................................................................................98 Floor Structures............................................................................................................................. 100 Duct Couplings .............................................................................................................................. 100 Duct Supports ................................................................................................................................ 101 Duct Inserts ..................................................................................................................................... 102 Junction Boxes ............................................................................................................................... 103 Distribution Ducts ....................................................................................................................... 104 Feeder Ducts ................................................................................................................................... 105 Enclosed Feeder Ducts ............................................................................................................. 106 Junction Boxes in Enclosed Feeder Ducts ................................................................... 107 Two-level Enclosed Feeder Duct Systems .................................................................... 108 Trench Ducts ................................................................................................................................... 110 Using a Trench Duct ................................................................................................................... 112 Cover Plates for Trench Ducts .............................................................................................. 113 Removing Trench Duct Cover Plates ............................................................................... 115 Compartments in Trench Ducts .......................................................................................... 117 Enclosing Underfloor Duct in Concrete ....................................................................... 118 Options for Enclosing Underfloor Duct......................................................................... 118 Enclosing Duct in the Slab ..................................................................................................... 119 Help Main TOC Print Search Search Find Find Quit vi Table of Contents Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Design Guidelines for Underfloor Ducts .................................. 120 Introduction .................................................................................................................................... 120 Feeder Duct Size ........................................................................................................................... 121 Feeder Duct Capacity ................................................................................................................ 121 Distribution Duct Sizes ............................................................................................................ 123 Insert Duct Sizes ........................................................................................................................... 124 Space Requirements for Trench Ducts ........................................................................... 125 Slab Thickness Requirements for Enclosing Duct ................................................... 126 Advantages and Disadvantages of Enclosing Duct with Fill ........................... 127 Fill Thickness Requirements for Enclosing Duct ...................................................... 129 Telecommunications Closet Considerations (for Underfloor Ducts) ......................................................................................................... 131 Introduction .................................................................................................................................... 131 Telecommunications Closets in the Core of a Multistory Building ............. 132 Telecommunications Closet Occupying One-quarter of a Floor ................... 133 Terminating Ducts in Telecommunications Closets............................................... 134 Help Main TOC Print Search Search Find Find Quit vii Table of Contents Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Design Procedure for an Underfloor Duct System ............. 136 Designing Underfloor Duct for Telecommunications Systems ...................... 136 General Rule for Spacing Ducts .......................................................................................... 141 Example of Duct Capacity ...................................................................................................... 144 Allocating Feeder Duct to Distribution Duct ............................................................ 146 Using Preset Inserts .................................................................................................................... 148 Determining Insert Spacing .................................................................................................. 150 Using Afterset Inserts................................................................................................................ 151 Performing a Final Design Check ...................................................................................... 152 Designing a Two-level Duct System ............................................ 154 Introduction .................................................................................................................................... 154 Using a One-way Metal Pan Joist Floor Design ........................................................ 155 Positioning Distribution Duct in the Slab ................................................................... 156 Intersecting Feeder and Distribution Ducts............................................................... 157 Feeder Beams ................................................................................................................................. 159 Help Main TOC Print Search Search Find Find Quit viii Table of Contents Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Cellular Floor Systems .......................................................................... 161 Introduction .................................................................................................................................... 161 Examples of Cellular Floor Systems ................................................................................. 163 Typical Cellular Arrangement .............................................................................................. 165 Standard Cellular Steel Floor Modules .......................................................................... 166 Components of a Closed Cellular Unit ........................................................................... 171 Help Main TOC Print Search Design Considerations for Cellular Floors ............................... 172 Introduction .................................................................................................................................... 172 Design Considerations .............................................................................................................. 173 Cellular Floor Capacity ............................................................................................................. 174 Providing Sufficient Cells........................................................................................................ 175 Search Find Find Quit ix Table of Contents Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Service Fittings for Underfloor or Cellular Systems .......... 176 Introduction .................................................................................................................................... 176 Sizes of Service Fittings ........................................................................................................... 177 Dedicated In-floor Service Fittings .................................................................................. 178 Advantages of Dedicated In-floor Service Fittings ................................................ 180 Designing for In-floor Fittings ............................................................................................. 181 Using Preset Fittings .................................................................................................................. 181 Using Afterset Fittings.............................................................................................................. 182 Fitting Housing Size ................................................................................................................... 183 Fitting Openings ........................................................................................................................... 184 Carpet Openings ...................................................................................... 185 Introduction .................................................................................................................................... 185 Cutting Carpet Openings ........................................................................................................ 186 Carpet Openings Over Trench Duct ................................................................................. 187 Help Main TOC Print Search Search Find Find Quit General Conduit Distribution .......................................................... 188 Introduction .................................................................................................................................... 188 x Table of Contents Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Design Considerations for Conduit Distribution................. 190 Suitable Conduit ........................................................................................................................... 190 Unsuitable Conduit ..................................................................................................................... 191 Acceptable Conduit Runs ....................................................................................................... 192 Unacceptable Conduit Runs.................................................................................................. 193 Recommended Conduit Capacity ...................................................................................... 194 Bend Radii for Conduits ........................................................................................................... 195 Designs with Conduit Bends ................................................................................................ 196 Using Three Bends in Conduit ............................................................................................. 197 Conduit Terminations ................................................................................................................ 198 Completing Conduit Installation ....................................................................................... 199 Help Main TOC Print Search Search Find Pierce Wye Conduit System .............................................................. 200 Find Recommended Uses ................................................................................................................... 200 Advantages of Wye Couplings ............................................................................................. 201 Installing Wye Couplings ........................................................................................................ 202 Quit xi Table of Contents Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Pull Boxes for Conduits........................................................................ 204 Installing Boxes ............................................................................................................................. 204 Slip-sleeves and Gutters .......................................................................................................... 206 Using Slip-sleeves or Gutters ............................................................................................... 207 Sizes and Purposes of Boxes, Slip-sleeves, and Gutters ...................................... 208 Boxes for Pulling and Looping Cable .............................................................................. 209 Placing Pull Boxes in Conduit Sections ......................................................................... 210 Choosing a Pull Box Size ......................................................................................................... 211 Access Floors .............................................................................................. 212 Introduction .................................................................................................................................... 212 Floor Components ....................................................................................................................... 213 Stringered Systems ..................................................................................................................... 215 Freestanding and Cornerlock Systems ........................................................................... 216 Help Main TOC Print Search Search Find Find Quit Design Considerations for Access Floors ................................. 217 Minimum Finished Floor Height......................................................................................... 217 Building Structure ....................................................................................................................... 218 Building Layout ............................................................................................................................. 219 Floor Penetrations ....................................................................................................................... 220 Bonding and Grounding .......................................................................................................... 220 xii Table of Contents Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Floor Panel Materials ................................................................................................................. 221 Floor Panel Coverings ............................................................................................................... 222 Load-bearing Capacity ............................................................................................................. 223 Running Telecommunications Cables ............................................................................. 225 Electrical Power Circuits .......................................................................................................... 226 Terminating Electrical Power Circuits ............................................................................. 226 Effects of Air Plenum Use on Cabling ............................................................................. 227 Ceiling Distribution Systems ............................................................ 228 Introduction .................................................................................................................................... 228 Acceptable Methods of Distribution ............................................................................... 229 Ceiling Zones Method ............................................................................................................... 230 Typical Ceiling Zone Distribution Using Conduit ................................................... 231 Illustration of Ceiling Zones ................................................................................................. 232 Help Main TOC Print Search Search Find Find Quit xiii Table of Contents Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems General Design Guidelines for Ceiling Systems ................... 234 Introduction .................................................................................................................................... 234 Determining Adequate Ceiling Space ............................................................................ 235 Choosing the Ceiling Panels ................................................................................................. 236 Restrictions on Ceiling Cabling .......................................................................................... 237 Ceiling Zone Conduit Restrictions .................................................................................... 237 Pathway and Cable Support.................................................................................................. 238 Termination Space ....................................................................................................................... 240 Cable Tray Design for Ceiling Systems....................................... 241 Cable Tray Systems ...................................................................................................................... 241 Cable Tray Fittings ....................................................................................................................... 243 Cable Tray Accessories .............................................................................................................. 243 Types of Cable Trays ................................................................................................................... 244 Cable Tray Dimensions ............................................................................................................. 245 Capacity of Cable Trays ............................................................................................................ 249 Supporting Cable Trays ............................................................................................................ 250 Marking and Grounding Cable Trays ............................................................................... 251 Help Main TOC Print Search Search Find Find Quit xiv Table of Contents Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Conduit and Raceway Design for Ceiling Systems ............. 252 Ceiling Zone Method Using Conduit ............................................................................... 252 Zone Conduit Size ....................................................................................................................... 253 Overhead Ceiling Raceway Method ................................................................................. 254 Typical Overhead Ceiling Raceway System ................................................................. 255 Raceway Size ................................................................................................................................... 255 Overhead Ceiling Raceways and Fittings ..................................................................... 256 Designing a Ceiling Raceway System ............................................................................. 257 Cabling Guidelines for Ceiling Pathways ................................. 261 Help Main TOC Print Search Search Managing Cabling ....................................................................................................................... 261 Find Work Area Distribution for Ceiling Systems ........................... 264 Find Utility Columns .............................................................................................................................. 264 Damaging Support Channels ............................................................................................... 264 Concealing Cables in Walls or Partitions ...................................................................... 265 Attaching Utility Columns ...................................................................................................... 266 Quit xv Table of Contents Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Other Pathways (Miscellaneous).................................................... 269 Introduction .................................................................................................................................... 269 Perimeter Raceway Systems .................................................................................................. 270 Using Perimeter Raceway Systems ................................................................................... 272 Overfloor Ducts ............................................................................................................................. 273 Molding Raceways ....................................................................................................................... 274 Open Office Distribution Systems .................................................................................... 275 Telecommunications Closets............................................................ 277 Overview ............................................................................................................................................ 277 Help Main TOC Print Search Search Find Outlet Boxes ............................................................................................... 278 Wall-mounted Outlets ............................................................................................................... 278 Cover Plates ..................................................................................................................................... 279 Larger Outlet Boxes................................................................................................................... 279 Mounting Telecommunications Outlets on Walls ................................................... 280 Mounting Outlets Above Counters and Cabinets ................................................... 282 Find Quit xvi Table of Contents Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Undercarpet Telecommunications Cable (UTC).................... 284 Introduction .................................................................................................................................... 284 Using UTC .......................................................................................................................................... 285 UTC Restrictions ............................................................................................................................ 286 Reversing the Direction of UTC .......................................................................................... 287 Prerequisites for Installing UTC .......................................................................................... 288 Preparing the Floor Surface .................................................................................................. 289 Storing UTC ...................................................................................................................................... 290 Using UTC with Undercarpet Power Cables ................................................................ 292 Designing a Layout Using UTC ............................................................................................ 293 Transition Points in Columns................................................................................................ 296 Transition Box Guidelines ....................................................................................................... 297 Transition Box Sizes .................................................................................................................... 298 Referenced Standards........................................................................... 299 Help Main TOC Print Search Search Find Find Quit Introduction .................................................................................................................................... 299 Standards and Specifications ............................................................................................... 300 xvii Figures Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Figure 4.1: Horizontal cabling to two individual work areas ......................................................... 11 Figure 4.2: UTP work area cable ........................................................................................................................ 38 Figure 4.3: Eight-position jack pin/pair assignments ( T568A) (front view of connector)............................................................................................................................... 39 Help Main TOC Figure 4.4: Optional eight-position jack pin/pair assignments ( T568B) (front view of connector)............................................................................................................................... 40 Print Figure 4.5: 568SC adapter with simplex and duplex plugs ............................................................. 46 Search Figure 4.6: Two 150-ohm STP-A outlet connectors .............................................................................. 48 Figure 4.7: Horizontal cabling link .................................................................................................................. 62 Figure 4.8: Horizontal cabling channel ........................................................................................................ 64 Figure 4.9: Single-level junction box ........................................................................................................ 103 Figure 4.10: Distribution ducts ....................................................................................................................... 104 Search Find Find Figure 4.11: Two-level duct system .............................................................................................................. 109 Figure 4.12: Trench duct in a cellular floor ............................................................................................. 110 Quit Figure 4.13: Single section of trench duct .............................................................................................. 111 Figure 4.14: Trench duct on cellular floor ............................................................................................... 114 Figure 4.15: Cover plate lifter and cover plate ..................................................................................... 116 Figure 4.16: Insert ducts ..................................................................................................................................... 124 Figure 4.17: Feeder duct in slab..................................................................................................................... 130 Figure 4.18: Typical underfloor duct layout in a multistory building ................................... 132 Figure 4.19: Telecommunications closets - ¼ of a floor plan ...................................................... 133 xviii Figures Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Figure 4.20: Duct capacity ................................................................................................................................. 144 Figure 4.21: Distribution duct system ........................................................................................................ 155 Figure 4.22: Distribution duct in the slab ............................................................................................... 156 Help Main TOC Figure 4.23: Two-level system ......................................................................................................................... 157 Figure 4.24: Feeder beam ................................................................................................................................... 159 Print Figure 4.25: Cross-section of cellular plan system ............................................................................ 163 Figure 4.26: Cellular floor system (trench duct) .................................................................................. 164 Figure 4.27: Typical cellular arrangement ............................................................................................... 165 Figure 4.28: Dedicated in-floor service fittings (staggered module system) ................... 179 Figure 4.29: Cutting carpet ............................................................................................................................... 186 Search Search Find Figure 4.30: A typical underfloor conduit system .............................................................................. 188 Figure 4.31: Underfloor conduit extended to individual outlets ............................................. 189 Find Figure 4.32: Placing bends and outlet boxes ........................................................................................ 203 Figure 4.33: Recommended box configurations .................................................................................. 205 Quit Figure 4.34: Stringered access floor system .......................................................................................... 214 Figure 4.35: Using home-run conduit ........................................................................................................ 231 Figure 4.36: Typical zoned ceiling ................................................................................................................ 232 Figure 4.37: Conduit-based ceiling zone .................................................................................................. 233 Figure 4.38: Overhead ceiling raceway system .................................................................................... 255 Figure 4.39: Raceways and fittings............................................................................................................... 256 xix Figures Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Figure 4.40: Attaching utility columns ...................................................................................................... 267 Figure 4.41: Perimeter raceway ...................................................................................................................... 272 Figure 4.42: Molding raceways ....................................................................................................................... 274 Help Main TOC Figure 4.43: Reversing direction of UTC ................................................................................................... 287 Figure 4.44: Storing UTC in folds in the floor fitting ........................................................................ 290 Print Figure 4.45: Storing UTC in coils ................................................................................................................... 290 Figure 4.46: Storing UTC in undercarpet folds ..................................................................................... 291 Figure 4.47: Transition points .......................................................................................................................... 296 Search Search Find Find Quit xx Tables Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Table 4.1: Cable lengths ............................................................................................................................................ 7 Table 4.2: Work area copper cable lengths to a multi-user telecommunications outlet assembly .................................................................................................................................................... 29 Help Main TOC Table 4.3: Categories for UTP cable ................................................................................................................ 42 Table 4.4: Typical ranges of cable diameter .............................................................................................. 91 Print Table 4.5: Number of cables ................................................................................................................................ 92 Table 4.6: Feeder ducts ........................................................................................................................................ 108 Table 4.7: Duct sizes .............................................................................................................................................. 123 Table 4.8: Space requirements ........................................................................................................................ 125 Table 4.9: Thickness requirements ............................................................................................................... 126 Table 4.10: Enclosing duct with fill .............................................................................................................. 127 Table 4.11: Thickness requirements ............................................................................................................ 129 Search Search Find Find Table 4.12: Guidelines for terminating ducts ........................................................................................ 135 Table 4.13: Cellular floor steel decks .......................................................................................................... 167 Quit Table 4.14: General sizes of fittings ............................................................................................................. 177 Table 4.15: Bend radii guidelines .................................................................................................................. 195 Table 4.16: Adapting designs ........................................................................................................................... 196 Table 4.17: Slip-sleeves and gutters ............................................................................................................ 206 Table 4.18: Minimum space requirements in pull boxes having one conduit each in opposite ends of the box.......................................................................................................... 211 xxi Tables Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Table 4.19: Coverings ............................................................................................................................................ 222 Table 4.20: Load capacity ................................................................................................................................... 223 Table 4.21: Guidelines for choosing ceiling panels ........................................................................... 236 Help Main TOC Table 4.22: Cable trays ......................................................................................................................................... 244 Table 4.23: Cable trays (common types) ................................................................................................... 246 Print Table 4.24: Recommended sizes .................................................................................................................... 298 Table 4.25: Standards ............................................................................................................................................ 300 Search Search Find Find Quit xxii General Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems General Introduction Help Horizontal cabling systems consist of two basic elements: TOC • • Horizontal Cable and Connecting Hardware (also called “horizontal cabling”) provide the means for transporting telecommunications signals between the telecommunications outlet/connector in the work area and the horizontal cross-connect in the telecommunications closet. These components are the “contents” of the horizontal pathways and spaces. Horizontal Pathways and Spaces (also called “horizontal distribution systems”) are used to distribute and support horizontal cable and connecting hardware between the work area outlet and the telecommunications closet. These pathways and spaces are the “container” for the horizontal cabling. Print Search Search Find Find Quit NOTE: The term “horizontal” evolved from the horizontal orientation that was typical of this segment of building cabling. However, the physical orientation of cabling has no bearing on its classification as either horizontal or backbone. 1 General Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Introduction, continued Help The horizontal cabling system includes: TOC • Telecommunications outlets in the work area. • Cables and transition or consolidation point connectors installed between work area outlets and the telecommunications closet. • Cross-connect blocks and patch panels. • Jumper and patch cords used to configure horizontal cable connections in the telecommunications closet. • Spaces, pathways and structures used to distribute and support horizontal cabling. NOTE: Horizontal cables do not include work area cables or equipment cables. However, the length and type of cable required to connect telecommunications equipment to the horizontal cabling will significantly affect end-to-end system performance and should be taken into account when planning any system. Print Search Search Find Find Quit 2 General Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Introduction, continued Help Horizontal cabling characteristically: TOC • Contains more cable than backbone cabling. • Is less accessible than backbone cabling. Therefore, the costs (in materials, labor, and occupant disruption) of making changes in horizontal cabling can be very high. To avoid these costs, horizontal cabling should be able to handle a broad range of user applications. The choice of cable media and distribution methodology is critical to the horizontal cabling system’s ability to accommodate diverse user needs and applications. In addition, the horizontal distribution system should be designed to make maintenance and relocation as easy as possible. Print Search Search Find Find Quit 3 General Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Design Considerations Help The telecommunications distribution designer should ensure that the system’s design: TOC • Print • Makes optimum use of the ability of the horizontal cabling system to accommodate change. Is comprised of standards-based components, assuring vendor independence. When designing horizontal distribution systems, the designer must observe the requirements of this chapter. In addition, all design and construction of horizontal cabling systems shall comply with ANSI/NFPA 70 (Ref. 4.1 in “Referenced Standards”), also referred to as the National Electrical Code ® or “NEC,” except where other authorities or codes impose a more stringent requirement or practice. In Canada, refer to CSA C22.1, the Canadian Electrical Code (CEC), Part 1. For other safety regulations, refer to Chapter 2, “Codes, Standards, and Regulations” in this manual. Search Search Find Find Quit 4 Horizontal Cable and Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Introduction Help The requirements in this section are harmonized with the horizontal cabling requirements specified in ANSI/TIA/EIA-568-A (Ref. 4.2 in “Referenced Standards”). In Canada, refer to CSA T529. TOC NOTES: Search • For installations outside of the United States and Canada, other national or international cabling specifications may apply. The internationally recognized standard for premises cabling is ISO/IEC 11801 (Ref. 4.3 in “Referenced Standards”). In Europe, the applicable cabling specification is CENELEC EN 50173 (Ref. 4.4 in “Referenced Standards”). • Specification ANSI/TIA/EIA-568-A supersedes TIA/EIA Technical Systems Bulletins TSB-36, TSB40-A, and TSB53. Print Search Find Find Quit • Additional TSBs and amendments related to telecommunications cabling and a revised version of ANSI/TIA/EIA-568-A are currently under development by TIA working groups. 5 Horizontal Cable and Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Design Considerations Help Horizontal cabling must be designed to accommodate diverse user applications, including: TOC • Voice communications. Print • Data communications. Search • Local area networks (LANs). The designer should also consider incorporating other building information systems (e.g., CAT V, alarms, security, audio, other telecommunications systems) when selecting and designing horizontal cabling. In addition to accommodating existing telecommunications needs, consider accommodating a diversity of applications in order to reduce or even eliminate the need for horizontal cabling changes as user requirements evolve. Search Find Find Quit To provide for a building’s future cabling needs, the horizontal cabling must: • Provide flexible cable distribution to work area locations. • Facilitate ongoing maintenance and relocation. • Accommodate future changes in equipment and services. 6 Horizontal Cable and Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Cable Lengths Help The maximum lengths of horizontal distribution cables are shown in the following table. TOC Print Table 4.1: Cable lengths Horizontal Cables . . . Must Be No More Than . . . Search From the horizontal cross-connect to the outlet/connector 90 m (295 ft.) long. Search Used for patch cords and cross-connect jumpers in the horizontal cross-connect 6 m (20 ft.) long. (See NOTES.) Find Find Quit These limits apply to all types of horizontal cable. 7 Horizontal Cable and Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Cable Lengths, continued Help NOTES: TOC In establishing limits on horizontal cable lengths, a 10-m (33-ft.) allowance was made for the combined length of patch cables and cables used to connect equipment in the work area and telecommunications closet. All equipment cables should meet the same performance requirements as the patch cords. Equipment cables differ from patch cables and cross-connect jumpers in that they attach directly to active equipment; patch cables and crossconnect jumpers do not attach directly to active equipment. The 6-m (20-ft.) maximum length specified for patch cables does not include additional cable lengths needed to connect to active equipment. For example, if 3 m (10 ft.) of cable is used for each work area connection, the 10-m (33-ft.) total allowance provides for up to 7 m (23 ft.) of combined length per channel for patch cables and equipment cables in the telecommunications closet. Print Search Search Find Find Quit 8 Horizontal Cable and Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Topology Help Horizontal cabling shall be installed in a star topology. Each work area outlet must be cabled directly to a horizontal cross-connect in the telecommunications closet except when a consolidation point is required to connect to open office cabling or a transition point is required to connect to undercarpet cable. Horizontal cabling should be terminated in a telecommunications closet which is on the same floor as the area being ser ved. TOC NOTES: • Splices are not permitted for twisted-pair horizontal cabling. Find • Bridged taps (multiple appearances of the same cable pairs at several distribution points) are not permitted in horizontal cabling. Find Print Search Search Quit Cabling between telecommunications closets is considered part of the backbone cabling. Such connections between closets may be used for configuring “virtual bus” and “virtual ring” cabling schemes using a star topology. 9 Horizontal Cable and Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Consolidation and Transition Points Help Horizontal cabling may not contain more than one consolidation point or transition point between different forms of the same cable type (i.e., from round cable to flat undercarpet cable). TOC Consolidation point and transition point connectors must meet the performance and reliability requirements specified in ANSI/TIA/EIA-568-A. In Canada, refer to CSA T529. Search Print Search Find Find Quit 10 Horizontal Cable and Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Horizontal Cabling Schematic Help The following illustration represents horizontal cabling to two individual work areas. TOC Print Figure 4.1: Horizontal cabling to two individual work areas Work Areas 3 m (10 ft.) 3 m (10 ft.) Telecommunications Closet Horizontal Horizontal Cross-Connect Cabling Search Optional Transition or Consolidation Point Search Find 90 m (295 ft.) Find 4-Pair 100-Ohm Unshielded Twisted-Pair Cable (Category 3 or Higher) One of the Three Horizontal Cabling Options Quit Legend Telecommunications Outlets Cross-Connect Symbol Mechanical Termination Symbol - + 11 Horizontal Cable and Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Horizontal Cabling Schematic, continued Help NOTES: TOC • Provided that the minimum requirements are met for horizontal cabling to each individual work area, additional cables and outlets may be provided to support other applications such as C ATV. • Label all cables that are left unterminated in walls or other horizontal spaces according to the requirements of ANSI/TIA/ EIA-606 (Ref. 4.5 in “Referenced Standards”). In Canada, refer to CSA T528. Cables that extend to outlet boxes must be covered with an outlet faceplate and identified for telecommunications use only. Although only two cable runs are required, the pathway design should allow for at least three cable runs per individual work area, to facilitate additions and changes as the user’s needs evolve. Print Search Search Find Find Quit 12 Horizontal Cable and Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Cable Slack Help When cable runs are being installed, consider providing additional slack at both ends to accommodate future cabling system changes. Although the exact amount of slack required depends on the size and layout of the connecting hardware of the telecommunications closet and the work area, the recommended minimum amount of slack at the: TOC • Telecommunications closet is 3 m (10 ft.). Search • Outlet is: – 1 m (3.3 ft.) for optical fiber cables. – 30 cm (12 in.) for twisted-pair cables. Include the slack in all length calculations to ensure that the horizontal cable does not exceed 90 m (295 ft.). Print Search Find Find Quit 13 Horizontal Cable and Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Grounding and Bonding Considerations Help When applicable, horizontal cabling and connecting hardware must be grounded and bonded in compliance with ANSI/NFPA 70 requirements and practices, except where superseded by other authorities or codes. In Canada, refer to CSA C22.1. Improper grounding of telecommunications cabling poses a serious safety risk, and increases the cables’ susceptibility to electromagnetic interference. TOC Print Search Search When grounding telecommunications cabling, ensure that: • • The installation conforms with proper practices and codes (ANSI/TIA/EIA-607 [Ref. 4.6 in “Referenced Standards”], ANSI/NFPA 70, and local building codes). In Canada, refer to CSA T527 and CSA C22.1. An approved ground is available at the telecommunications closet for: Find Find Quit – Cross-connect frames. – Patch panel racks. – Active telecommunications equipment. – Test apparatus used for maintenance and testing. (See Chapter 6, “ Telecommunications Closets and Rooms.”) 14 Horizontal Cable and Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Grounding and Bonding Considerations, continued Help • TOC Grounding requirements of equipment manufacturers are properly followed (when compatible with required electrical codes). For further guidelines on bonding and grounding, see Chapter 20, “Grounding, Bonding, and Electrical Protection.” Print Search Search Find Find Quit 15 Horizontal Cable and Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Electromagnetic Interference (EMI) Help The designer should treat potential sources of electromagnetic interference (EMI) as a primary consideration when selecting types of horizontal cabling and designing the layout of horizontal pathways. Typical sources of EMI include: TOC Print • Electric motors, transformers, and fluorescent lighting that reside in close proximity to telecommunications cabling. Search • Copiers that share space with telecommunications cables and equipment. Search • Power cables that support such equipment. One way to avoid electromagnetic interference is to maintain physical separation between possible sources and the telecommunications cabling. (See “Avoiding Electromagnetic Interference [EMI]” in this chapter.) For additional information, see Chapter 21, “Electromagnetic Compatibility.” Although optical fiber and shielded cable have been the traditional choice for buildings with high levels of ambient EMI, performance-enhanced unshielded twisted-pair (UTP) cabling, such as Category 5, offers a degree of noise immunity that ensures reliable transmission in most environments. Consult with cable suppliers and installation guidelines to determine the level of noise immunity offered by various grades of UTP cable. Find Find Quit 16 Horizontal Cable and Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Administration Help Follow systematic methods and procedures for proper labeling and management of horizontal cabling. For details on guidelines and requirements related to the administration of horizontal cabling systems, refer to Chapter 6, “ Telecommunications Closets and Rooms,” and ANSI/TIA/EIA-606. In Canada, refer to CSA T528. TOC Identify the performance category of each UTP cabling run at both ends of the run. Locate the markings so that they are: Search • Clearly visible after installation. Find • Easily distinguishable from any markings that appear on individual components (e.g., connecting hardware, cables). Print Search Find Quit 17 Horizontal Cable and Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Crossovers Help A cabling system crossover is a transposition of pairs or optical fibers that permits each pair or fiber to connect to a transmitter on one end and a receiver on the other. When cabling system crossovers are required, they must be documented and labeled accordingly. TOC For 100-ohm UTP cabling links, make all connections straight through with no crossovers between pairs or conductors. If crossovers are required for a particular UTP application, they may be used only outside of the horizontal cabling system. Special application-specific equipment cords or adapters are sometimes used for this purpose. For optical fiber cabling systems, Section 12 of ANSI/TIA/EIA-568-A provides explicit guidelines that govern the use of crossovers. In Canada, refer to CSA T529. These guidelines assure that each optical fiber cabling link is installed in a pair-wise crossover orientation in which the fibers of a pair identified as Position A and Position B at one end will be reversed and identified as Position B and Position A (respectively) at the other end. This pair-wise crossover for optical fibers is achieved by using connector polarity and labeling methodologies that apply to horizontal cables, patch cords, equipment cords, and 568SC adapters. Print Search Search Find Find Quit 18 Horizontal Cable Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Cable Types Help The three types of cables recognized for use in horizontal cabling are: TOC Horizontal Cable • Four-pair 100-ohm unshielded twisted-pair (UTP). • Two-fiber 62.5/125 µm optical fiber cable. • Two-pair 150-ohm shielded twisted-pair (STP). Print Search IMPORTANT: Having one of these generic names does not guarantee that a cable meets the requirements of ANSI/TIA/EIA-568-A or of CSA T529. Search The wire gauge used for 100-ohm UTP cabling is typically 24 AWG (0.50 mm). UTP cables that are 22 AWG (0.63 mm) are also permitted for horizontal cabling if they meet the requirements of ANSI/TIA/EIA-568-A or, in Canada, CSA T529. Four-pair screened, twisted-pair cables that meet the same transmission requirements as 100-ohm UTP for the applicable performance category may also be used. Specifications for 100-ohm screened cabling components and systems are under study by TIA Task Group PN-3193. Find Find Quit The wire gauge used for 150-ohm STP-A cabling is typically 22 AWG (0.63 mm). 19 Horizontal Cable Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Horizontal Media Selection Help To support both voice and data communications in a commercial building, a minimum of two recognized cables must be run to two telecommunications outlets at individual work area locations. The two outlets at each work area allow support for multiple telecommunications applications at the desk. TOC The horizontal cabling runs to each individual work area shall consist of telecommunications outlets connected to: • Four-pair 100-ohm UTP cable (Category 3 or higher). Print Search Search Find and • Any one of the following (depending on the anticipated needs of work area occupants): Find Quit – Four-pair 100-ohm UTP cable (Category 5 recommended). – Two-fiber 62.5/125 µm multimode optical fiber cable. – Two-pair 150-ohm STP-A cable. 20 Horizontal cable Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Horizontal Media Selection, continued Help NOTES: • Unless otherwise required to support specific applications, designers should specify either 100-ohm twisted-pair cabling or multimode optical fiber cabling for the second outlet. TOC • Outlets that serve an individual work area may be located in one or more faceplates. Search Although 50-ohm coaxial cable is allowed in ANSI/TIA/EIA-568-A and CSA T529, it is not recommended for new installations. If specific applications require other types of cabling, the other types may not be installed in place of any of the cabling listed above. To determine the suitability of the cabling types listed above for specific applications, consult systems suppliers, equipment manufacturers, and systems integrators. Print Search Find Find Quit 21 Horizontal cable Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Hybrid Cables Help A hybrid cable is a cable consisting of a common sheath containing: TOC • Two or more cable types. Print or • Two or more units of the same cable type. NOTE: The NEC refers to a cable comprised of optical fiber and copper as a composite cable. IMPORTANT: Cables that are bound together by strings or bands (e.g., a helical wrap) are subject to the hybrid cable requirements specified in ANSI/TIA/EIA-568-A. Because this type of process is known to affect transmission characteristics of the cables, they must be re-qualified prior to installation. Search Search Find Find Quit Among the disadvantages of hybrid cables are that they: • Tend to limit flexibility of the cabling system. • Are more difficult to administer than discrete cables. • Occupy excess pathway space due to greater bend radii or when one of the hybrid components is damaged or unused. 22 Horizontal cable Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Hybrid Cables, continued Help One of the advantages of hybrid cables is that they may reduce installation costs in instances where multiple cables cannot be pulled as a group. TOC Hybrid cable may be used if : • Crosstalk meets the ANSI/TIA/EIA-568-A requirements for hybrid cables. In Canada, use the requirements in CSA T529. • Each cable type within the sheath meets the appropriate: Print Search Search - Transmission requirements. Find - Color-code requirements. Find Quit 23 Horizontal Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems General Help Connecting hardware for horizontal cabling includes: TOC Horizontal Connecting Hardware • Telecommunications outlet/connectors. • Connectors used in the horizontal cross-connect. • Consolidation point and transition point connectors (optional). All connecting hardware used for horizontal cable connections must meet the requirements for reliability, safety, and transmission performance specified in: • ANSI/TIA/EIA-568-A. In Canada, refer to CSA T529. • ANSI/NFPA 70. In Canada, refer to CSA C22.1. Equipment Connections Do not connect horizontal cables directly to telecommunications equipment. Instead, use suitable connecting hardware and equipment cable to make the connection. Locate patch panels and cross-connect blocks so that the combined length of cables and cords used to connect equipment in the work area and telecommunications closet, plus the patch cable, do not exceed 10 m (33 ft.). Print Search Search Find Find Quit 24 Horizontal Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Telecommunications Outlets Help Mount telecommunications outlets/connectors securely at work area locations. Terminate all horizontal cables that are not reserved for future use with the standard telecommunications outlet/connector specified for that cable type. Locate work area outlets so that the cable required to reach work area equipment will be no more than 3 m (10 ft.) long. TOC For information about the accessibility requirements for telecommunications outlets/connectors, see “Mounting Telecommunications Outlets on Walls” and “Mounting Outlets Above Counters and Cabinets” in this chapter. Search Print Search Find Find Quit 25 Horizontal Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Cabling Adapters Help Some networks and services require application-specific electrical components (e.g., impedance matching devices) for equipment in the telecommunications closet, the work area, or both. These components, called “cabling adapters,” must not be installed as a part of the horizontal cabling. When required, cabling adapters must be placed outside of the horizontal cross-connect and telecommunications outlet/connector. This ensures that the cabling infrastructure will retain its ability to accommodate a variety of services without modifications to the horizontal cabling. TOC NOTE: Cabling adapters used in the work area or telecommunications closet may have a detrimental effect on the transmission performance of the telecommunications cabling system. Therefore, it is important to consider each cabling adapters’ compatibility with the horizontal cabling and the equipment to which it connects before attaching it to the telecommunications network. Print Search Search Find Find Quit 26 Horizontal Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Open Office Cabling Systems Help Many commercial buildings are now being designed to be easily reconfigured as its occupants’ needs evolve. This trend has led to “open office” and “open work space” designs in which the available space is divided by modular furniture and partitions, rather than by fixed walls. TOC In open office designs, the movable partitions often serve as the delivery system for the horizontal cabling. In these cases, it is important that the delivery system provides a means for: • • Routing and protecting horizontal cables that are not otherwise concealed or protected (e.g., behind walls, under floors, above suspended ceilings). Serving any offices in a work-space cluster that are not within the prescribed distance of 3 m (10 ft.) from a fixed wall outlet. Print Search Search Find Find Quit Two cabling adaptations, specified in TIA/EIA TSB75 (Ref. 4.7 in “Referenced Standards) to address these issues include: • Multi-user telecommunications outlet/assembly. • Consolidation point. These adaptations are explained in the sections which follow. 27 Horizontal Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Multi-user Telecommunications Outlet Assembly Help In a multi-user telecommunications outlet assembly arrangement, a furniture cluster that typically includes eight users or less is provided with a fixed outlet connector assembly that serves the cluster. Equipment is directly connected to the multi-user telecommunications outlet assembly by work area cables. Horizontal cables extend from the multi-user telecommunications outlet assembly to the horizontal cross-connect in the telecommunications closet using horizontal pathways. TOC A multi-user telecommunications outlet assembly serves as a telecommunications outlet/connector for each piece of equipment in the furniture cluster, and therefore must meet the interface requirements for the type of cabling that it serves. If a single horizontal cable (e.g., a hybrid cable) serves multiple outlets through a multi-user telecommunications outlet assembly, the cable must meet the appropriate transmission performance requirements as specified in ANSI/TIA/EIA-568-A (in Canada, CSA T529) to assure that diverse telecommunications applications served by multiple telecommunications outlets do not inter fere with each other. Find NOTE: TIA is currently studying hybrid transmission requirements and crosstalk specifications in a shared-sheath cabling environment. Print Search Search Find Quit 28 Horizontal Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Multi-user Telecommunications Outlet Assembly, continued Help Because a multi-user telecommunications outlet serves an entire office cluster, provisions have been made to allow work area cables to extend beyond 3 m (10 ft.), depending upon the length of the building cable. Acceptable work area cable lengths are shown in the following table. The lengths given are based on a combined length of 7 m (23 ft.) or less for equipment cables, patch cords, and jumpers in the telecommunications closet. TOC Print Search Search Table 4.2: Work area copper cable lengths to a multi-user telecommunications outlet assembly Length of Building Cables Maximum Length of Work Area Cables Maximum Combined Length of Work Area Cables, Patch Cords, and Equipment Cable 90 m (295 ft.) 3 m (10 ft.) 10 m (33 ft.) 85 m (279 ft.) 7 m (23 ft.) 14 m (46 ft.) 80 m (262 ft.) 11 m (36 ft.) 18 m (59 ft.) 75 m (250 ft.) 15 m (50 ft.) 22 m (72 ft.) 70 m (230 ft.) 20 m (66 ft.) 27 m (89 ft.) Find Find Quit 29 Horizontal Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Multi-user Telecommunications Outlet Assembly, continued Help The sum of the values in each row of the table above diminishes as the horizontal cable gets shorter because work area cables (i.e., stranded cables) are allowed up to 20 percent more attenuation than solid horizontal cables are allowed. Do not use work area cables whose length exceeds 20 m (66 ft.). TOC A multi-user telecommunications outlet assembly must be labeled to include the maximum length of work area cables. This labeling is in addition to the labeling described in ANSI/TIA/EIA-606 (in Canada, CSA T528). Work area cables extending from the multi-user telecommunications outlet assembly to the work area device must also be uniquely identified and labeled. NOTE: A multi-user telecommunications outlet assembly may not be used for any purpose except its defined purpose of making a direct connection to work area equipment. Never use a multi-user telecommunications outlet as a cross-connect point. Print Search Search Find Find Quit 30 Horizontal Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Consolidation Point (CP) Help A consolidation point (CP) serves as a location for connection between horizontal cables extending from building pathways and cables extending into furniture pathways; it is not a user interface. A consolidation point provides the convenience of rearranging dedicated outlets for each furniture cluster. However, it has the disadvantage of introducing additional loss and crosstalk in the horizontal cabling. TOC Print Search Search A consolidation point allows standard horizontal cables to be extended into furniture clusters and terminated on telecommunications outlet/connectors that are dedicated to each individual user. In this type of implementation, the total length of building cable is restricted to 90 m (295 ft.) and allows the work area cable to be kept to 3 m (10 ft.) or less. If a single horizontal cable (i.e., hybrid cable) serves multiple outlets through a consolidation point, the cable must meet the appropriate transmission performance requirements as specified in ANSI/TIA/EIA-568-A (in Canada, CSA T529) to assure that diverse applications served by multiple telecommunications outlets do not interfere with each other. Find Find Quit 31 Horizontal Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Consolidation Point (CP), continued Help NOTE: TIA is currently studying hybrid transmission requirements and crosstalk specifications in a shared-sheath copper cabling environment. TOC A consolidation point is similar to a transition point in that its purpose is for connection between horizontal cables extending from building pathways and cables extending into furniture pathways, rather than to serve as a user interface. However, the consolidation point does not include a transition to undercarpet cable like the transition point does. Search NOTE: A consolidation point may not be used for any purpose except its defined purpose of making a direct connection to telecommunications outlets. Never use a consolidation point as a cross-connect point or for direct connections to active equipment. Find Print Search Find Quit For further information on recommended implementations for open office cabling, see “Open Office Distribution Systems” in this chapter. 32 Horizontal Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Locating Multi-user Telecommunications Outlet Assemblies and Consolidation Points Multi-user telecommunications outlet assemblies shall be located in fully accessible, permanent locations such as building columns and permanent walls. Multi-user telecommunications outlet assemblies shall not be located in ceiling spaces, under access flooring, or any obstructed area. Multi-user telecommunications outlet assemblies shall not be installed in furniture unless that unit of furniture is permanently secured to the building structure. A consolidation point is a location for connection between horizontal cables extending from building pathways and cables extending into furniture pathways. Consolidation point shall be located in fully accessible, permanent locations such as building columns and permanent walls. Consolidation points shall not be installed in furniture unless that unit of furniture is permanently secured to the building structure. The use of suspended ceiling space or access floor space for consolidation points is generally not recommended but is acceptable provided the following guidelines are met. Help TOC Print Search Search Find Find Quit 33 Horizontal Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Locating Multi-user Telecommunications Outlet Assemblies and Consolidation Points, continued • • When no appropriate permanent building structure exists for the consolidation point to feed a furniture cluster other than suspended ceiling or access floor space. The consolidation point shall be sized and cabled so that it meets the communication requirements of the “zone” it serves. If the floor space requirements change for an existing consolidation point, then the consolidation point should be reconfigured to accommodate the new requirements. • Consolidation points shall not be located in any obstructed area. • The consolidation point shall be fully accessible above the suspended ceiling or beneath the access floor. • Building fixtures, equipment or heavy furniture (e.g., file cabinets weighing 45 kg [100 lb.] or more) shall not compromise access. • Access to the consolidation point should not disturb occupants and must not require zone occupants to relocate in order to provide access to or egress from the consolidation point. Help TOC Print Search Search Find Find Quit 34 Horizontal Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Locating Multi-user Telecommunications Outlet Assemblies and Consolidation Points, continued • The ceiling or floor tile shall be clearly and permanently marked and identified as containing a consolidation point. When ceilings or access floors are replaced, ensure that the CP locations are identified and remarked when the new ceiling or access floor is in place. • The consolidation point shall be administered according to ANSI/TIA/EIA-606. • Connecting hardware shall be protected from physical abuse and foreign substances by an enclosure meeting the requirements of UL 1863 Communications Circuit Accessories or equivalent test standard and be marked accordingly. • When the consolidation point is located in an air-handling space, such as a plenum ceiling or access floor, the complete consolidation point assembly (enclosure with connecting hardware) shall meet the requirements of UL 2043 Fire Test for Heat and Visible Smoke Release for Discrete Product and Their Accessories Installed in Air-handling Spaces or equivalent test standard and shall be marked accordingly. Manufacturers instructions shall be followed for installation to ensure compliance to heat and smoke test conditions. Help TOC Print Search Search Find Find Quit 35 Horizontal Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Locating Multi-user Telecommunications Outlet Assemblies and Consolidation Points, continued • Under no circumstances shall active telecommunications equipment (e.g., hubs and routers) be placed in ceiling or access floor spaces. In all cases, the use of consolidation points in ceiling or access floor spaces shall conform to ANSI/NFPA 70, including Section 300-22 (c) for other spaces used for environmental air (in Canada, refer to the applicable CSA requirements) and local building codes. Telecommunications outlet connectors and multi-user telecommunications outlet assemblies must not be located in the ceiling space. CAUTION: Do not place active telecommunications equipment in the ceiling or access floor space. In accordance with Article 300-22 (b) of ANSI/NFPA 70 the consolidation point shall not be located inside an environmental air-handling duct. Help TOC Print Search Search Find Find Quit 36 Horizontal Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems 100-ohm UTP Cable Outlets Help Each four-pair 100-ohm UTP cable must be terminated in an eight-position modular jack at the work area. The telecommunications outlet/connector must meet the standard interface requirements and meet or exceed the minimum reliability requirements of specification IEC 603-7 (Ref. 4.8 in “Referenced Standards”). Terminate the telecommunications outlet/connector directly to the horizontal cable with insulation displacement connections, and mount it on the outlet faceplate so that it is accessible for work area connections. TOC All connectors that provide electrical connections between 100-ohm UTP cables must meet the requirements of ANSI/TIA/EIA-568-A. In Canada, refer to CSA T529. The following illustration shows a UTP work area cable being mated to one of two UTP outlet connectors mounted on a faceplate. Print Search Search Find Find Quit 37 Horizontal Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems 100-ohm UTP Cable Outlets, continued Help Figure 4.2: UTP work area cable TOC Cable Side Print Search Faceplate Search 8-Position Telecommunications Outlet/Connector Find Find Quit Modular Plug User Side + 38 Horizontal Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems 100-ohm UTP Cable Outlets, continued Help The jack and pin/pair assignments for these modular jacks are shown in the following illustrations. These assignments are compatible with all known data applications intended to operate over 100-ohm twisted-pair cable. TOC Figure 4.3: Eight-position jack pin/pair assignments (T568A) (front view of connector) Search Pair 2 Pair 3 Pair 1 Print Search Find Pair 4 Find 1 2 3 4 5 6 7 8 W-G G W-O BL W-BL O W-BR BR Quit Jack Positions - + 39 Horizontal Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems 100-ohm UTP Cable Outlets, continued Help Optional pin/pair assignments T568B (to accommodate certain kinds of eightpin cabling systems) are shown in the following illustration: TOC Figure 4.4: Optional eight-position jack pin/pair assignments (T568B) (front view of connector) Print Search Pair 3 Search Pair 2 Pair 1 Pair 4 Find 1 2 3 4 5 6 7 8 W-O O W-G BL W-BL G W-BR BR Jack Positions Find - Quit + NOTE: The colors indicated are associated with horizontal UTP cable. Color coding for equipment cables, work area cables, patch cables, and jumpers may var y. 40 Horizontal Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems 100-ohm UTP Cable Outlets, continued Help United States government publication FIPS PUB 174 (Ref. 4.9 under “Referenced Standards” in this chapter) recognizes only the T568A assignments. TOC 100-ohm UTP Performance Categories Search There are five performance categories for 100-ohm UTP horizontal cabling. Both cable and connecting hardware categories are specified in ANSI/TIA/EIA568-A (in Canada, CSA T529). Cables and connecting hardware must be rated for Category 3 or higher to be used in horizontal cabling. The connecting hardware and patch cords used for a horizontal run must be rated in the same category as the cable or in a higher category. The categories for UTP cable and connecting hardware are defined in the following table. Print Search Find Find Quit NOTE: For detailed information on transmission principles, see Chapter 26, “Principles of Transmission.” 41 Horizontal Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems 100-ohm UTP Performance Categories, continued Help Table 4.3: Categories for UTP cable TOC Category Definition Category 1 This category consists of basic telecommunications and power-limited circuit cables. There are no electrical performance tests or bandwidth requirements for this classification. Category 1 cabling must not be used in horizontal cabling systems. Category 2 Category 3 This category consists of cables specified up to 1 MHz by UL Subject 444 and Subject 13 (Ref. 4.10 in “Referenced Standards”). Category 2 cabling must not be used in horizontal cabling systems. This category consists of cables and connecting hardware specified up to 16 MHz. Category 3 components represent the minimum transmission performance acceptable for 100-ohm UTP cabling systems. Print Search Search Find Find Quit 42 Horizontal Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems 100-ohm UTP Performance Categories, continued Help Table 4.3: Categories for UTP cable, continued TOC Category Category 3, Category 4 Category 5 Definition continued The performance of Category 3 cabling links corresponds to application Class C links as specified in ISO/IEC 11801 and CENELEC EN 50173. This category consists of cables and connectors specified up to 20 MHz. This category consists of cables and connectors specified up to 100 MHz. These components represent the highest level of transmission performance specified for UTP cabling systems. Print Search Search Find Find Quit The performance of Category 5 cabling links corresponds to application Class D links as specified in ISO/IEC 11801 and CENELEC EN 50173. 43 Horizontal Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Category Selection Help Choosing which category of UTP cabling to install is primarily a budgetary decision. Using components from the highest category possible is the best long-term investment because it minimizes changes over the life of the cabling system. If possible, install components from only one category throughout the system. This will reduce the confusion and expense that can result from long-term administration of a multiple-category UTP system. TOC Print Search Search Find Find Quit 44 Horizontal Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems 62.5/125 µm Optical Fiber Each horizontal 62.5/125 µm optical fiber cable must be accessible at the telecommunications outlet/connector in the work area by way of a duplex SC-style adapter, as specified in ANSI/TIA/EIA-604-3 and IEC 874-14 (SC-D) (Ref. 4.13 in “Referenced Standards”). The connector and adapter are also identified as “Type 568SC.” Terminate each horizontal optical fiber directly to a simplex plug or duplex plug which is mated to a back-to-back female adapter mounted on a faceplate. The other end of the adapter is the outlet interface that is accessible for work area connections via a duplex plug connector. In situations where a base of BFOC/2.5 (also called “ST ”) connectors and adapters is already installed, users may continue to use connectors that meet the specifications in ANSI/TIA/EIA-604-2 and IEC 874-10 (Ref. 4.14 in “Referenced Standards”) and BFOC/2.5 adapters for future additions and changes to the optical fiber cabling. Help TOC Print Search Search Find Find Quit For methods and guidelines on the proper installation and connection of optical fiber cabling, refer to ANSI/TIA/EIA-568-A (in Canada, CSA T529). 45 Horizontal Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems 62.5/125 µm Optical Fiber, continued Help The following illustration shows a 568SC adapter with simplex and duplex plugs (for horizontal cables and work area cords, respectively). TOC Figure 4.5: 568SC adapter with simplex and duplex plugs Print Search Cable Side Search Simplex Connectors Find Find Duplex Connectors User Side SC Quit - 568SC Adapter + 46 Horizontal Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems 150-ohm STP-A Cable Outlet Help Each 150-ohm STP-A cable must be terminated with an outlet that meets the interface requirement specified by IEC 807-8 (Ref. 4.11 in “Referenced Standards”). Terminate the outlet connector directly to the horizontal cable from the telecommunications closet and mount it on the outlet faceplate so that it is accessible for work area connections. The 150-ohm STP-A outlet connector is designed to be “hermaphroditic,” meaning that two identical units will connect when oriented face-to-face at an angle of 180° to each other. TOC Pin/pair assignments must follow the specifications in ISO/IEC 8802-5 (Ref. 4.12 under “Referenced Standards” in this chapter). All connectors that provide electrical connections between 150-ohm STP-A cables must meet the requirements of ANSI/TIA/EIA-568-A (in Canada, CSA T529). Connectors that are designed to meet the extended frequency requirements specified for STP-A components often carry the symbol E to make it possible to differentiate them from connectors designed to meet the former standard. The following illustration shows two 150-ohm STP-A outlet connectors. Print Search Search Find Find Quit 47 Horizontal Connecting Hardware Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems 150-ohm STP-A Cable Outlet, continued Help Figure 4.6: Two 150-ohm STP-A outlet connectors TOC Print Search Search Find 4-Position Data Connector Find Quit 4-Position Data Connector - + 48 Cross-connect Jumpers and Patch Cords Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems General Help Cables used to configure additions, moves, and changes are as critical to transmission performance as embedded horizontal cable runs. Cross-connect jumpers and cables used for patch cords must meet the performance requirements described in ANSI/TIA/EIA-568-A (in Canada, CSA T529). For UTP cabling, the jumpers and patch cables must be rated at the same performance category or at a higher performance category as the cabling to which it connects. TOC Using factory-terminated patch cords can reduce performance variations caused by poor or inconsistent field cabling practices. Find Cross-connect Jumpers and Patch Cords All equipment cables in the work area and the telecommunications closet should meet the same performance requirements as the patch cords. Print Search Search Find Quit 49 Cross-connect Jumpers and Patch Cords Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Length Requirements Help Horizontal cross-connect jumpers and patch cords should not exceed a length of 6 m (20 ft.) per link. System designers should plan for a combined cable length of 10 m (33 ft.) for patch cords and for equipment connections in the work area and telecommunications closet. This length is in addition to the 90 m (295 ft.) of cable allowed between the horizontal cross-connect and the telecommunications outlet/connector. TOC Print Search Search Find Find Quit 50 Cabling Practices Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems General Cabling Practices Help Connector and cable components that meet transmission performance requirements are not sufficient in themselves to ensure adequate performance of the installed cabling system. The performance of the installed system may be degraded by cabling practices relating to: TOC • Connector terminations. • Cable installation and management. • Use of cross-connect jumpers and patch cords. • Multiple connections in close proximity. Print Search Search Find Find Cable Management Practices Performance specifications for cable and connecting hardware are based on proper installation and cable management. If recommended cabling precautions and installation methods are not followed, cabling components may not perform to specifications. These performance deficiencies may be apparent on initial installation or may show up through reduced performance over time. Quit 51 Cabling Practices Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Cable Management Practices, continued Help Pay strict attention to manufacturer’s guidelines on bend radii and maximum pulling tension during installation. Notice that the recommended bend radius for a cable during installation is typically greater (more severe) than the recommended bend radius once the cable is installed. This is to minimize tension and deformation as the cable passes around corners. The maximum pull force guideline for four-pair horizontal UTP cables is 110 N (25 lb). Meeting this guideline avoids stretching the conductors during installation and associated transmission degradation. TOC In cable pathways and the telecommunications closet, use appropriate cable routing and dressing fixtures to organize and effectively manage the different cable types. The cable management precautions that should be followed include: • Print Search Search Find Find Quit Eliminating cable stress caused by: – Tension in suspended cable runs. Limit spans to 1.5 m (5 ft.) or less. – Tightly clinched cable bundles. Keep jacket deformation to a minimum. – Twisting the cable jacket during installation. IMPORTANT: Never use staples to install telecommunications cabling. 52 Cabling Practices Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Cable Management Practices, continued Help • TOC Reducing untwisting of copper pairs by stripping back only as much cable jacket as is required to perform connecting hardware terminations (with allowance for excess length that may be trimmed off during termination). Print NOTE: The pair twist requirement, listed in “Connector Termination Practices” in this chapter, does not apply to jacket removal. Search • Search Ensuring that horizontal cable bend radii are no less than four times the cable diameter for: – UTP. • Find – STP-A. Find Ensuring that the cable bend radii for twisted-pair cables containing optical fiber is either 10 times the cable diameter or 30 mm (1.2 in.), whichever is larger. Consult with cable manufacturers to determine if an additional bend allowance is required for specific cable brands and types. Quit 53 Cabling Practices Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Cable Management Practices, continued Help Cable bend radius requirements minimize the effects of bends on the transmission performance of installed cabling links. These requirements are distinct from the bend radius specifications for conduits, which assure that the cable is not damaged during installation. Consult the manufacturer’s specifications for the minimum bend radius during installation. For further information, see “Bend Radii for Conduits” in this chapter. TOC Print Search Search Find Find Quit 54 Cabling Practices Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Connector Termination Practices Help Horizontal cables must be terminated on connecting hardware that meets the applicable requirements for the type of cabling used. For example, the UTP cabling is rated at the same category as the lowest performance component used in the link. TOC Because horizontal and backbone cables are always terminated on separate connectors, use patch cords or jumpers to make connections between horizontal cables and backbone cables. While all transmission parameters are sensitive to transmission discontinuities caused by connector terminations, near-end crosstalk (NEXT ) performance of twisted-pair systems is particularly sensitive to conductor untwisting and other installation practices that disturb pair balance and cause impedance variations. In addition to signal degradation, improper termination practices can create loop antenna effects which result in signal radiation levels that exceed regulatory emission requirements. Print Search Search Find Find Quit 55 Cabling Practices Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Connector Termination Practices, continued Help To prevent these problems, always: TOC • Remove only as much cable jacket as is required for termination and trimming. • Follow the manufacturer’s instructions for mounting, termination, and cable management. • Minimize the amount of untwisting in a pair as a result of termination to connecting hardware. For UTP cabling, maintain pair twists as close as possible to the termination point. The amount of untwisting must not exceed: Print Search Search Find Find – 25 mm (1.0 in.) for Category 3 and Category 4 cables. – 13 mm (0.5 in.) for Category 5 cables. Quit NOTE: This requirement is intended to minimize untwisting of wire pairs and the separation of conductors within a pair. It is not intended as a twist specification for cable or jumper construction. 56 Cabling Practices Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Connector Termination Practices, continued Help The installation requirements specified in ANSI/TIA/EIA-568-A (in Canada, CSA T529) must be observed for all types and categories of connecting hardware. For termination fields that require frequent access (e.g., cross-connects used for configuring network moves and changes), one way to control termination consistency is by using factory-assembled patch cables and patch panels that meet the appropriate performance requirements. Jumpers can provide comparable performance, but typically require a higher skill level to make moves, adds or changes. TOC Print Search Search Find Find Quit 57 Work Area Cables Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems General Help Work Cables Work areaArea cables (also called “line cords” or “station cords”) extend from the TOC telecommunications outlet to the work area equipment. The work area equipment may include (but is not limited to): Print • Telephones. • Data terminals. • Computers. The telecommunications distribution designer must convey the importance of good work area components and cabling practices to the customer. Although work area cabling is critical to assuring good horizontal link performance, it is often subject to abuses (e.g., sub-grade cables and cords whose lengths exceed the recommended limit of 3 m [10 ft.]). Search Search Find Find Quit NOTE: When horizontal cabling must be adapted to accommodate specific user needs, make the adaptations outside (i.e., beyond) the telecommunications outlet. For further information, see “Cabling Adapters” in this chapter. 58 Work Area Cables Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Work Area Cables/Cords Help Cables used to connect work area equipment are as critical to transmission performance as embedded horizontal cable runs. For work area cords and other equipment cables that connect to the horizontal cabling, follow the performance requirements described in ANSI/TIA/EIA-568-A (in Canada, CSA T529). UTP cabling must also meet or exceed the near-end crosstalk (NEXT ) requirements for the appropriate category. TOC Print Search Search The combined length of cables and cords used to connect equipment in the work area and telecommunications closet, plus the patch cable, must not exceed 10 m (33 ft.). Find Find Quit 59 Cabling Links and Cabling Channels Cabling Links and Cabling Channels Introduction Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Help The terms used to distinguish between horizontal cabling subsystems with and without equipment cords are: TOC • Cabling links. Print • Cabling channels. Search These terms are explained in the sections which follow. Search Find Find Quit 60 Cabling Links and Cabling Channels Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Cabling Links Help A horizontal cabling link encompasses all components of the horizontal cabling subsystem that are covered by ANSI/TIA/EIA-568-A and ISO/IEC 11801 (in Canada, CSA T529). These components include the: TOC Print • Telecommunications outlet. • Cable between the outlet and the horizontal cross-connect. • Transition or consolidation point connector (optional). Search • Patch panels or connecting blocks in the horizontal cross-connect. Find • Jumper or patch cords that join the patch panels or connecting blocks. The term “basic link” refers to a horizontal cabling link that includes only the: • Horizontal cable (without patch cords or jumpers). • Telecommunications outlet. • Connecting hardware on which the horizontal cable terminates in the telecommunications closet. NOTE: The “basic link test configuration” includes 2 m (7 ft.) of flexible cable on each end for connections to test instrumentation, as specified in TIA/EIA TSB67. Search Find Quit 61 Cabling Links and Cabling Channels Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Cabling Links, continued Help A horizontal cabling link is distinguished from a horizontal cabling channel because it does not include: TOC • Equipment cables/cords in the telecommunications closet. Print • Cords in the work area that extend beyond the telecommunications outlet/ connector. The following illustration shows a horizontal cabling link. For further information on cross-connections and interconnections, see Chapter 6, “ Telecommunications Closets and Rooms.” Search Search Find Find Figure 4.7: Horizontal cabling link Telecommunications Closet Quit Work Area 1 < 6m Horizontal Cable (<90 m) (TO) (TP or CP) (HC) - + 62 Cabling Links and Cabling Channels Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Cabling Links, continued Help In the illustration above: TOC • “ TO” indicates the telecommunications outlet. • “ TP” or “CP” indicates the transition point or consolidation point. • “HC” represents the horizontal cross-connect. Search • Optional horizontal cabling elements include the transition point or consolidation point, patch cords/jumpers (l 1 ), and connecting hardware used for a cross connection scheme to active equipment in the telecommunications closet. Search When a UTP cabling link has components from different performance categories, the overall link is rated in the same category as the lowest-rated component. For example, a UTP cabling link which consists of Category 5 components, except for a single Category 4 connector, is rated as a Category 4 link, not as a Category 5 link. A cabling link that contains only the horizontal cable (without patch cords or jumpers), the telecommunications outlet, and the connector on which the horizontal cable terminates in the telecommunications closet is sometimes referred to as a “basic link.” Print Find Find Quit 63 Cabling Links and Cabling Channels Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Cabling Channels Help A horizontal cabling channel encompasses all the elements of the horizontal cabling link, plus the equipment cords in the telecommunications closet and the work area. The horizontal cabling channel includes all the cabling elements required to support telecommunications applications intended to operate over horizontal cabling. TOC Connectors used to attach equipment cords to network equipment are not considered a part of the horizontal cabling channel. Search The illustration below shows a horizontal cabling channel. For further information on cross-connections and interconnections, see Chapter 6, “ Telecommunications Closets and Rooms.” Print Search Find Find Quit Figure 4.8: Horizontal cabling channel Telecommunications Closet Work Area 1 Horizontal Cable (<90 m) 2 3 (TO) (TP or CP) (HC) - + 1 + 2 + 3 < 10 m 64 Cabling Links and Cabling Channels Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Cabling Channels, continued Help In the illustration above: TOC • “ TO” indicates the telecommunications outlet. • “ TP” or “CP” indicates the transition point or consolidation point. • “HC” represents the horizontal cross-connect. Search • Optional horizontal cabling elements include the transition point or consolidation point, patch cords/jumpers (l 1 ), and connecting hardware used for a cross- connection scheme to active equipment in the telecommunications closet. Search • Work area and equipment cables marked as “l 2 ” and “l 3 ” provide connections to premises equipment and are included as part of the horizontal cabling channel. Print Find Find Quit 65 Cabling Links and Cabling Channels Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Verification Testing Help For guidelines on verification testing of : TOC • Optical fiber cabling links, see Chapter 12, “Optical Fiber Recommendations” and Annex H of ANSI/TIA/EIA-568-A. Print • UTP cabling links, see TIA/EIA TSB67 (Ref. 4.15 in “Referenced Standards”). Search TIA/EIA technical bulletin TSB67 also specifies requirements for test instruments, as well as field measurement practices and procedures that will ensure repeatable measurements of installed UTP links and channels. Test results that meet the performance verification requirements specified in ANSI/TIA/EIA-568-A and TIA/EIA TSB67 are not sufficient to establish compliance with these documents. To be in compliance, the links must also meet the documents’ requirements for: • Cabling length and topology. • Component per formance and reliability. • Installation practices. NOTE: Specifications for performance testing of shielded cabling components and systems are under study by TIA Task Group PN-3193. Search Find Find Quit 66 Horizontal Pathways and Spaces Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Introduction Help Horizontal Pathways and Spaces Horizontal pathways and spaces consist of structures that conceal, protect, TOC and support horizontal cables between the: • Telecommunications outlet/connector used to connect work area equipment (voice, data, and video) at the work area. Print Search and • Horizontal cross-connect in the serving telecommunications closet. Horizontal pathways and spaces are generally referred to in this chapter as “horizontal distribution systems.” When designing a building, the layout and capacity of the horizontal distribution systems must be thoroughly documented in floor plans and other building specifications. The telecommunications distribution designer is responsible for ensuring that these systems have built-in flexibility to accommodate tenant movement and expansion. Search Find Find Quit 67 Horizontal Pathways and Spaces Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Introduction, continued Help The horizontal distribution system must be designed to handle all types of telecommunications cable (e.g., telephone, data, video). When determining the type and size of the pathway: TOC Print • Consider the quantity and size of cables that the pathway is intended to house. Search • Allow for growth of the area served over the planning cycle. Search NOTE: All design and construction for distribution systems must meet or exceed national and local codes and standards. The content of this section is harmonized with horizontal pathways and spaces requirements specified in ANSI/TIA/EIA-569-A (Ref. 4.16 under “Referenced Standards” in this chapter). Find Find Quit 68 Horizontal Pathways and Spaces Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Design Considerations Help Select and design the type and layout of horizontal distribution systems carefully. After a building is constructed, it may be more difficult to gain access to horizontal cabling than backbone cabling. Therefore the skill, effort, and time required to make horizontal cabling changes can be very high. TOC When selecting and designing horizontal distribution systems, it is important to consider the design’s ability to: Search • Accommodate cabling changes. • Minimize occupant disruption when horizontal pathways and spaces are accessed. In addition to providing for current occupant needs, the horizontal distribution system design must: • Facilitate ongoing maintenance of horizontal cabling. • Accommodate future additions to and changes in cabling, equipment, and services. The pathway design should allow for a minimum of three cable runs per individual work area. Although only two cables per work area are required, the additional pathway capacity is needed to facilitate future additions and changes as the user’s needs evolve. Print Search Find Find Quit 69 Horizontal Pathways and Spaces Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Electromagnetic Interference (EMI) Help Electromagnetic interference is an important consideration in the design of pathways and spaces. Providing separation distance from sources of EMI for these elements of the telecommunications infrastructure inherently provides separation of their contents, i.e., the equipment and cable. TOC Locate telecommunications pathways and spaces away from sources of electromagnetic interference such as electrical power wiring and transformers, radio frequency (RF) sources and transmitters, large motors and generators, induction heaters, arc welders, x-ray equipment and copiers. Search The following precautions should be considered to reduce interference from sources of EMI: • Use grounded metallic pathways to limit inductive noise coupling between the telecommunications cabling and sources of EMI. Cable installation close to a grounded metallic sur face will also reduce inductive noise. • Use sheathed cables (e.g., Romex) or other branch circuit cable constructions (e.g., taped, twisted or bundled) that prevent separation of the line, neutral and grounding conductors to minimize electromagnetic interference from the power conductors. • The use of surge protectors in branch circuits can limit the propagation of electrical surges and associated interference. Print Search Find Find Quit 70 Horizontal Pathways and Spaces Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Electromagnetic Interference (EMI), continued Help For other guidelines concerning EMI, see 8.2.1.5 and 10.3 of ANSI/TIA/EIA-569-A and Chapter 21, “Electromagnetic Compatibility.” Separation requirements between telecommunications and other types of circuits are provided in Article 800-52 of ANSI/NFPA 70. TOC General building considerations that have an impact on both safety and EMI include: Search • Structural lightning protection. • Electrical surge protection. • Grounding and bonding. • Print Search Find Faulty electrical wiring. Find Grounding and Bonding Quit IMPORTANT: Improper grounding of telecommunications pathways poses a serious safety risk. For details on grounding and bonding requirements, see Chapter 20, “Grounding, Bonding, and Electrical Protection.” Horizontal pathways must be grounded and bonded in compliance with the requirements and practices in ANSI/NFPA 70 (in Canada, CSA C22.1), except where other codes or authorities impose more stringent requirements. In addition to creating a serious safety risk, improper grounding of telecommunications pathways increases a cabling system’s susceptibility to EMI. 71 Horizontal Pathways and Spaces Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Grounding and Bonding, continued Help When grounding telecommunications pathways, ensure that: TOC • • The installation conforms with proper practices and codes (in the United States, ANSI/TIA/EIA-607, ANSI/NFPA 70, and local building codes; in Canada, CSA T527 and CSA C22.1). For further details, see Chapter 20, “Grounding, Bonding, and Electrical Protection.” An approved ground is available in the telecommunications closet for crossconnect frames and patch panel racks. For further details, see Chapter 6, “Telecommunications Closets and Rooms.” Firestopping All horizontal pathways that penetrate fire-rated barriers must be firestopped in accordance with the applicable codes. For further details on firestopping, see Chapter 22, “Firestopping.” Print Search Search Find Find Quit 72 Horizontal Pathways and Spaces Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Wet Locations Help Intrabuilding horizontal pathways shall be installed in “dry” locations that protect cables from moisture levels that are beyond the intended operating range of “inside” premises cable (see ANSI/TIA/EIA-568-A). For example, slab-on-grade construction where pathways are installed underground or in concrete slabs that are in direct contact with soil (e.g., sand, gravel, etc.) are considered to be “wet locations.” See ANSI/NFPA 70, Article 100, for definitions of damp, dry and wet conditions. TOC Print Search Search Hazardous Locations When telecommunications horizontal pathways or cabling are placed in a hazardous location, such as an explosive or combustible atmosphere, observe all requirements of the applicable electrical code. Find Find Quit Administration Use systematic methods and procedures for labeling and managing horizontal pathways and spaces. For details on guidelines and requirements for the color coding and administration of horizontal cabling systems, see Chapter 6, “ Telecommunications Closets and Rooms” and ANSI/TIA/EIA-606 (in Canada, CSA T528). 73 Horizontal Pathways and Spaces Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Types of Horizontal Pathways Help The main types of horizontal pathways are: TOC • Underfloor ducts (one-level or two-level). • Cellular floors. • Conduit. Search • Access (raised) floors. Search • Ceiling zones and grids. Many buildings require a combination of two or more of these systems to meet all distribution needs. For example, an office area in a building may require an underfloor or overhead system, while an isolated telecommunications outlet location in the same building may be best served by an individual conduit. Print Find Find Quit NOTE: Because some local codes specify the type of horizontal pathway to be used, check all applicable codes and regulations before selecting a type of pathway. 74 Advantages/Disadvantages of Various Distribution Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Underfloor and Cellular System Advantages Advantages/Disadvantages of Various Distribution Systems The advantages of underfloor duct or cellular floor distribution systems are Help TOC that they: • Provide: Print – Mechanical protection for cables. Search – Office layout flexibility. – Increased security. – Concealed and protected connecting devices in enclosed service fittings. – An aesthetic appearance on customers’ premises. • Search Find Find Reduce: – Service interruptions from damaged cables. Quit – Electrical interference. – Safety hazards. Cellular systems have the additional advantages of providing: • Above-normal capacity. • Frequent access at regular intervals along the cell. 75 Advantages/Disadvantages of Various Distribution Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Underfloor and Cellular System Disadvantages Help The disadvantages of underfloor duct and cellular floor systems are that: TOC • The initial cost (before the floor space is occupied) is high. • Junction boxes may become clogged. • Junction boxes or trench ducts must be made accessible, even when covered with carpet. • They are not conducive to furniture moves or environments that are subject to frequent changes in work area locations. In addition, if dedicated service fittings are not provided, the concrete floor must be drilled to place afterset inserts for cellular systems. This extra operation is expensive and time-consuming. Print Search Search Find Find Quit 76 Advantages/Disadvantages of Various Distribution Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Trench Duct Advantages Help The advantages of using a trench duct with an underfloor duct or cellular floor system are that a trench duct: TOC • Print • Makes it possible to put large cables or significant quantities of smaller cables in place. Allows significantly faster cable placing in new installations than other systems. Trench Duct Disadvantages The disadvantages of using a trench duct with an underfloor duct or cellular floor system are that trench duct distribution systems: • Are very difficult to fish through, unless they are provided with compartments 15 to 20 cm (6 to 8 in.) wide. • Are difficult to make level with the surrounding floor area. ( This difficulty is noticeable if feeder is placed between beams on a cellular metal floor, since the deck sags while the concrete is poured.) • Are usually more expensive to install than an enclosed feeder duct system. Search Search Find Find Quit 77 Advantages/Disadvantages of Various Distribution Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Trench Duct Disadvantages, continued Help • TOC Have trench covers that: – Give a “springing” sensation when walked on. – Act as a sound board. • Print – Are a problem to remove in carpeted areas. Search – Are a hazard or inconvenience for the building occupants when covers are removed. Search – Warp from repeatedly fastening the screws that level them. (Often the screws are not replaced and the covers are never made level.) Find Have cracks along the side of the covers that: – Permit dirt, wax, etc., to enter. Find Quit – Make it difficult to remove foreign matter. • Have floor tiles that: – Often come off the trench covers if epoxy is not used. – Chip and crack easily if outer and inner tile stops are not placed. 78 Advantages/Disadvantages of Various Distribution Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Advantages of Conduit Systems Help The advantage of underfloor conduit systems is their low initial installation cost for areas that have just a few outlets. This is particularly true where outlet locations are established (e.g., markets, information desks, public telephone locations). TOC Underfloor conduits may be used to: Print Search • Extend underfloor ducts to an outlet location on a wall or column. Search • Connect a baseboard raceway or movable partition raceway to a building cable distribution system. Find Find Disadvantages of Conduit Systems Quit The disadvantage of conduit systems is their limited flexibility. Cabling from outlets is exposed if desks are not located either: • Over floor outlets. or • Adjacent to wall outlets. 79 Advantages/Disadvantages of Various Distribution Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Access Floor Advantages Help Many designers consider the access (raised) floor system the best distribution system available. The advantages of access floor systems are that: TOC • They are aesthetically acceptable for office decor. Print • They are designed for high capacity. Search • Cabling is easily accessible across the entire floor. • Changes can be made quickly with little occupant disruption. • They are among the least costly of all distribution systems for making moves, additions, and changes. • • Cabling can be adapted to a wide variety of arrangements for optimum utilization of the available floor space. Search Find Find Quit The enclosed space between the subfloor and the access floor provides space for: – Accommodating spare cabling for present and future office technologies. – Other occupant needs (e.g., heating, cooling, power). 80 Advantages/Disadvantages of Various Distribution Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Access Floor Disadvantages Help The disadvantages of access floor systems are that they: TOC • Act as a sound board. • Have a high initial cost. • May require that tiles with access holes be replaced when furniture is moved. • May disrupt or be hazardous to office personnel when panels are removed. • Allow haphazard placement of cable and may be easily accessed by untrained and unqualified personnel. Print Search Search Find Find Quit 81 Advantages/Disadvantages of Various Distribution Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Ceiling System Advantages Help The advantages of ceiling distribution systems are that: TOC • The cost of setting up the system can be delayed until the floor space is rented. Print • They provide: Search – Good concealment. Search – A flexible way to distribute cables to desk locations. – Adequate space to place cables throughout the floor area. Find • Cable lengths are kept to a minimum. Find • Cable can be: Quit – Dedicated to serve a specific floor area. – Reused. • Work area outlets can be relocated short distances without replacing cables. • Additional cable can be placed easily with minimum inconvenience to tenants. • The initial cable needed can be quickly and easily placed to approximate locations before the ceiling is installed. 82 Advantages/Disadvantages of Various Distribution Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Ceiling System Disadvantages Help The disadvantages of ceiling distribution systems are that they: TOC • Are completely inaccessible over: Print – Plaster ceilings. – Spline ceilings. Search – Sealed air plenums. Search • May create electrical hazards or pick up noise interference from lighting fixtures and power circuits. Find • Can be put out of service accidentally by technicians working on other systems in the ceiling. Find • Require utility columns which may affect the aesthetics of the office. • Create hazards or interruptions for office workers when technicians must work on ladders during office hours. • Have advantages that are limited, to some degree, by the type of modular furniture used. Quit 83 Advantages/Disadvantages of Various Distribution Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Ceiling System Disadvantages, continued Help Ceiling systems may also damage ceilings or other office fixtures and furnishings. Specifically, ceiling systems may cause damage to: TOC • Print • • Ceiling tiles and rails due to pole movement. (Replacing ceiling tiles may cause a patchwork effect in the ceiling.) Ceiling rails or cause ceiling tiles to drop if cables are not properly supported. Furniture which may be soiled or damaged by falling debris or by technicians during service. Search Search Find Find Quit 84 Advantages/Disadvantages of Various Distribution Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Advantages of Undercarpet Telecommunications Cable (UTC) Help Undercarpet Telecommunications Cable (UTC) is used primarily in open office areas. The advantages of using UTC over using round cable are that UTC provides: TOC • Flexibility to: – Locate outlets anywhere on the floor without the limitations imposed by walls, ductwork, or utility poles. • Print Search Search – Delay finalizing office plans and cabling until immediately before the office is occupied. Find A useful distribution solution to difficult renovation projects. Find NOTE: Using carpet squares over UTC is recommended because carpet squares provide easy access for cabling changes. ANSI/NFPA 70, Article 328B, requires that undercarpet power cables (type FCC) be covered with carpet squares but does not specifically address UTC. In Canada, requirements for undercarpet cabling are found in CSA C22.1, sections 60-322 through 60-334. Quit 85 Advantages/Disadvantages of Various Distribution Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Disadvantages of Undercarpet Telecommunications Cable (UTC) Help The disadvantages of UTC systems are that they are: TOC • Often aesthetically poor because of “witness lines” that show through the carpet. • Susceptible to damage over time due to foot traffic, rolling loads and furniture placement. • Not easy to change or reroute without: – Removing the carpet. – Having a noticeable aesthetic impact. • Print Search Search Find Find Typically higher-loss and lower-performance than other cable alternatives. Quit 86 Advantages/Disadvantages of Various Distribution Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Poke-thru Disadvantages Help Because of the many drawbacks of poke-thru cabling, it is not recommended for horizontal cabling systems. Therefore, poke-thru distribution systems are not addressed in this chapter. TOC The disadvantages of a poke-thru system to the telecommunications system provider are: Search • Search • Additional time is required with the structural engineer to select hole locations. The floor cannot be penetrated in certain areas (e.g., over beams, column caps). • Cost and inconvenience of drilling core holes. • Noise interference can be picked up from electrical circuits and lighting fixtures. • Disturbance that workers servicing the cabling may cause to the occupants of the floors above and below. ( The occupants of a lower floor can even restrict access to their facility by workers providing service to tenants on the floor above.) Print Find Find Quit 87 Advantages/Disadvantages of Various Distribution Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Poke-thru Disadvantages, continued Help The disadvantages of a poke-thru system to the building owner and tenant are that: TOC • Drilling holes can cause structural damage. Print • Cables may be in locations where drilling is impossible. Search • Service may be interrupted. • Removing and replacing ceiling panels, drilling holes, and overtime work is expensive. • Find Employees’ work may be disrupted because of: – Core drilling noise. – Installers working over desks on ladders. • Search Find Quit During a fire, poke-thru holes that are not properly firestopped: – Allow drainage of water onto occupied floors when there is firefighting above. – Reduce the fire-resistant qualities of the floor. – Have an increased risk of passing liquids and dirt to adjacent floors. – Act as chimneys that allow gases to enter adjacent floors and/or air handling systems. 88 Sizing of Horizontal Pathways Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Introduction Help Sizing of Horizontal Pathways The size requirements for horizontal distribution pathways depend on the following considerations: TOC • Usable floor space served by the pathway. Print • Maximum occupant density (i.e., floor space required per individual work area). • Cable density (i.e., quantity of horizontal cables planned per individual work area). • Cable diameter. • Pathway capacity (requires that fill factor be taken into account). Search Search Find Find Quit Usable Floor Space The usable floor space (also called “office space”) is generally considered to be the building area used by occupants for their normal daily work functions. For planning purposes, this space should include hallways, but not other common areas of the building. 89 Sizing of Horizontal Pathways Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Occupant Density Help The standard floor space allocation used in an office environment is one individual work area for every 10 m 2 (100 ft 2 ) of usable floor space. TOC NOTE: In cases where the work area density will be greater than one office per 10 m 2 (100 ft 2 ) of usable floor space, or where there will be more than three outlets required for each work area, the pathway capacity must be increased accordingly. Print Search Search Cable Density Find The telecommunications distribution designer should plan for a pathway capacity that accommodates a minimum of three horizontal cable runs per individual work area. Although only two cable runs are required, additional capacity will facilitate additions and changes to horizontal cabling as user needs and applications evolve. Find Quit 90 Sizing of Horizontal Pathways Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Cable Diameter Help The following table lists typical ranges of cable diameter for three recognized horizontal cabling media. These values are provided for planning purposes only. It is strongly recommended that the distribution designer check the actual diameter of the cable being used before determining pathway size requirements. TOC Table 4.4: Typical ranges of cable diameter Search Print Search Horizontal Cable Type . . . Typical Range of Overall Diameter . . . Four-pair 100-ohm UTP 0.36 cm to 0.61 cm (0.14 in. to 0.25 in.) 62.5/125 µm Optical Fiber Cable 0.28 cm to 0.46 cm (0.11 in. to 0.18 in.) Find Two-Pair 150-ohm STP-A 0.79 cm to 1.1 cm (0.31 in. to 0.43 in.) Quit Find 91 Sizing of Horizontal Pathways Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Conduit Capacity Help The following table provides guidelines used by ANSI/TIA/EIA-569-A on cable capacity for conduits ranging from trade size ½ to trade size 4. In Canada, see CSA T530. TOC Table 4.5: Number of cables Search Print Search Find Find Quit - + 92 Sizing of Horizontal Pathways Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Conduit Capacity, continued Help The previous table provides guidelines on cable capacity for horizontal conduits that have no more than two 90-degree bends (180 degrees total) and are no longer than 30 m (98 ft.). Additional information on telecommunications conduit fill is provided in ANSI/TIA/EIA-569-A. TOC NOTES: • The table above shows the conduit fill ratio guidelines for horizontal cables; however, the number of cables which can be installed is actually limited by the allowed maximum pulling tensions of the cables. This fill requirement does not apply to sleeves, header ducts, underfloor systems, access floors, and conduit runs without bends and under 15 m (50 ft.). Fill ratios can be increased further by use of lubricants. Print Search Search Find Find Quit • The table above is based on 40% fill and a derating factor of 15% for each of two 90° bends: 100% - 15% - 15% = 70% 40% x 70% = 28% The TIA Working Group TR 41.8.3 has investigations pending on the subject of allowable fill for telecommunications pathways. 93 Sizing of Horizontal Pathways Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Conduit Capacity, continued Help Monitor pull force closely during installation to ensure that the manufacturer’s pull-force requirements are never exceeded. Pull force is determined by several factors, including the: TOC • Cable type and number. • Conduit type. • Conduit size. • Conduit length. • Conduit orientation. • Number and configuration of conduit bends. • Selection of lubricants used during installation. Print Search Search Find Find Quit Because the first few feet of cable may be damaged during the pulling operation, they should be cut off prior to terminating. Because of the possibility of damaging existing cables, as well as the other uncertainties involved, pulling new cables through a partially loaded conduit is generally not desirable. 94 Sizing of Horizontal Pathways Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Determining Conduit Size Help The following is a sample calculation to determine the size of a horizontal conduit, based on the preceding information and guidelines: TOC Step Print Determining the Floor Space That a Conduit Can Serve Example 1 Measure the usable floor space to 100 m 2 be served by the horizontal conduit. 2 Divide the usable floor space by the maximum occupant density (required per individual work area [IWA]) 3 Multiply by the maximum number of cables per individual work area. (See “Cable Density” in this chapter.) 100 m 2 ÷ 10 m 2 10 IWAs x (ft./in.) (1,000 ft 2 ) (1,000 ft 2 ) (100 ft 2 ) 10 IWAs 3 cables per IWA 30 Search Search Find Find Quit 95 Sizing of Horizontal Pathways Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Determining Conduit Size, continued Help Step TOC 4 5 Determining the Floor Space That a Conduit Can Serve Example (ft./in.) Determine the maximum diameter of the horizontal cable to be used. ( Telecommunications cables of different types may be placed together in the same conduit.) ∅ 0.61 cm (0.24 in) Use the table in “Conduit Capacity” in this chapter to determine the conduit size that is most suitable for holding a quantity of 30 cables with a diameter of 0.61 cm (0.24 in.) 63 cm Print Search Search Find (2½ in.) Find Quit 96 Sizing of Horizontal Pathways Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Determining Raceway Size Help Most raceways are provided with design guidelines, including fill factors from the manufacturer. While ANSI/NFPA 70, Chapter 3, applies generally to raceways, Article 300-1, Exception No. 5, clearly indicates that those fill requirements do not apply to telecommunications cabling. See Note 1 in “Conduit Capacity.” Different types of raceways have different requirements. See “raceway” definition in ANSI/NFPA 70, Article 100. In Canada, see CSA C22.1, Sections 12-900 through 12-2503. TOC Determining Duct Size The guideline used for planning duct capacity is 6.5 cm 2 (1.0 in 2 ) of crosssection for each 10 m 2 (100 ft 2 ) of usable floor space. This relationship applies to both feeder and distribution ducts and is based on the assumption of three cables per individual work area and one individual work area for every 10 m 2 (100 ft 2 ) of usable floor space. Print Search Search Find Find Quit NOTE: Special occupant needs or floor plans may require additional duct space . 97 Underfloor Duct Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Introduction Help Underfloor Duct Systems An underfloor duct system is a network of metal raceways embedded in TOC concrete which facilitates the distribution of horizontal cables (i.e., between telecommunications closets and work areas). Print NOTE: For information on the advantages and disadvantages of underfloor duct, see “Underfloor and Cellular System Advantages” and “Underfloor and Cellular System Disadvantages” in this chapter. Ducts are rectangular and may be used in: • Single, double, or triple runs. • Combinations of large and standard ducts, mixed to provide a larger or smaller capacity to match the needs of specific areas in a building. Search Search Find Find Quit Underfloor duct systems are made up of : • Feeder ducts (sometimes called “header ducts”) which carry cables from the telecommunications closet to the distribution ducts. • Distribution ducts, which distribute cables from a feeder duct to specific floor areas. 98 Underfloor Duct Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Introduction, continued Help Distribution ducts are installed with preset inserts to provide access to horizontal cables both during and after installation. Preset inserts are not required on feeder ducts that extend under passageways or into other places where access to the horizontal cabling is not required. TOC Depending on the floor structure, ducts may be designed in one-level or twolevel systems. Print Search Search Find Find Quit 99 Underfloor Duct Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Floor Structures Help Underfloor duct systems can be used with several types of floor structures, including: TOC • Monolithic pour. Print • Slab-on-grade. Search • Double pour. • Post-tensioned pour. When prefabricated concrete is used, set up the underfloor duct system before pouring the finish layer. For additional information on floor structure, see ANSI/TIA/EIA-569-A (in Canada, CSA T530). Search Find Find Quit Duct Couplings Couplings join ducts to form a system. The most common type of coupling is the sleeve-type coupling with set screws. 100 Underfloor Duct Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Duct Supports Help Duct supports hold a duct system in place. These supports: TOC • Space the ducts. • Raise or lower the ducts to a position parallel to the floor. • Secure the ducts while the concrete is being poured. Print Search Search Find Find Quit 101 Underfloor Duct Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Duct Inserts Help Duct inserts provide a place to make an opening in a distribution duct after the surrounding concrete is poured without disturbing the concrete. Insert openings allow floor service fittings to be attached in the future. TOC Distribution ducts must provide inserts for access or handhole units in order to allow changes in direction and provide access for pulling cables. Search There are two types of inserts: Search • “Preset” inserts are factory-installed. Find • “Afterset” inserts are field-installed. Preset inserts must be used for the underfloor duct system if the floor is a post-tensioned pour (i.e., where the steel is put under tension and the concrete is put under compression after the pour). For more information, see “Using Preset Inserts” in this chapter. Print Find Quit 102 Underfloor Duct Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Junction Boxes Help Place junction boxes at planned locations in a duct system to: TOC • Permit changes in the direction of the run. • Provide access to the system for pulling cables. The maximum length allowed between junction boxes and other access points is 18 m (60 ft.). The following is an example of a single-level junction box: Print Search Cover Plate Adjustable Ring Box-Leveling Screw Search Find Gasket Find Figure 4.9: Single-level junction box Quit Outside Ring Adjusting Screw Partition - + 103 Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Underfloor Duct Systems Chapter 4 - Horizontal Cabling Systems Distribution Ducts Help Distribution ducts are used to: TOC • Distribute cables from a feeder duct to specific floor areas. • Provide access to cables in a specific floor area. Print Examples of distribution ducts are shown in the following illustration. Search Figure 4.10: Distribution ducts Search Standard Large Flush-Type Find Find Quit Extra-Large - + (Use for Heavy Duty Electrical Work) Standard and Large Ducts with Ellipsoid Inserts (USA Only) 104 Underfloor Duct Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Feeder Ducts Help Feeder ducts are ducts which connect the telecommunications closet to the distribution ducts. Feeder ducts are available as either: TOC • Enclosed duct. Print or Search • Open trench. Feeder ducts may serve either underfloor duct or cellular floor systems. Whenever possible, locate feeder ducts under corridors to minimize interference with work areas during cabling changes. Separate different types of service (e.g., power, telecommunications) by providing a: • Separate feeder duct for each type of service. Search Find Find Quit or • Trench duct with barriers to separate the spaces for the different services. Access units that connect feeders to distribution ducts must be placed directly above the selected cells and be provided with grommets to prevent cable damage. 105 Underfloor Duct Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Feeder Ducts, continued Help “Jack-feeder” ducts are short lengths of feeder duct used to connect multiple distribution ducts together without a direct connection to the telecommunications closet. Jack-feeder ducts are used to maintain coverage of floor areas that would otherwise be isolated (e.g., areas adjacent to stairwells or columns). TOC Enclosed Feeder Ducts Enclosed feeder ducts are: Print Search Search Find • Large. Find • Blank (i.e., have no inserts). Quit • Installed with junction boxes attached. 106 Underfloor Duct Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Junction Boxes in Enclosed Feeder Ducts Help Provide junction boxes in enclosed feeder ducts: TOC • Where feeder and distribution ducts intersect. • With a minimum 13-cm (5-in.) diameter (or equivalent) handhole opening between the upper and lower level. ( This provides easy access for hands to bend cables.) If junction boxes are not provided at bends, consult the manufacturer for the derating of duct capacity. Print Search Search Find Find Quit 107 Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Underfloor Duct Systems Chapter 4 - Horizontal Cabling Systems Two-level Enclosed Feeder Duct Systems Help Two-level enclosed feeder duct systems combine blank and preset-insert ducts of different sizes to distribute telecommunications and electrical power services. The types of ducts, their locations, and their uses are explained in the following table. TOC Print Search Table 4.6: Feeder ducts Type of Duct Level Contains Search Large (blank) Lower Dedicated feeders from electrical power service panels and telecommunications closets. Find Standard (inserts) Upper Electrical power service. Large (inserts) Upper Telecommunications services. Find Quit 108 Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Underfloor Duct Systems Chapter 4 - Horizontal Cabling Systems Two-level Enclosed Feeder Duct Systems, continued Help An example of a two-level system appears in the following illustration. It depicts a typical implementation of the ducts described in the preceding char t. TOC Figure 4.11: Twolevel duct system Search Print Search Find This system uses: • Standard duct on the upper level for electrical power services. Find Quit - + • Large duct on the upper level for telecommunications services. • Large blank ducts on the lower level for feeders from electrical power closets and telecommunications closets. 109 Underfloor Duct Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Trench Ducts Help Trench ducts are specially-manufactured metallic troughs that are placed flush to a finished floor and used as feeder ducts. Distribution ducts are accessed through the bottom of the trench duct. TOC A trench duct (containing telecommunications and power lines) in a cellular floor is shown in the following illustration. Search Figure 4.12: Trench duct in a cellular floor Search Print Find Find Quit - + Power Telecommunications 110 Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Underfloor Duct Systems Chapter 4 - Horizontal Cabling Systems Trench Ducts, continued Help A single section of trench duct with its cover plate is shown in the following illustration. TOC Print Figure 4.13: Single section of trench duct Search Search Find Find Quit - + 111 Underfloor Duct Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Using a Trench Duct Help In normal designs, do not make trench duct your first choice. Although the duct cover is completely removable and the capacity is attractive (and can provide solutions to some problems), trench duct has inherent disadvantages as described in “ Trench Duct Disadvantages” in this chapter. TOC Despite their disadvantages, trench ducts can supplement enclosed feeder duct systems in cases where feeder ducts approach the telecommunications closet from a direction that would require one or more bends to position cables correctly in the closet. In these cases, the trench duct must extend far enough from the telecommunications closet to allow access to all enclosed feeders. Couple trench duct sections together and level them so that the duct’s top sur face is flush with the concrete. Install grommets in all openings between trench duct and distribution duct. Print Search Search Find Find Quit 112 Underfloor Duct Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Cover Plates for Trench Ducts Help Cover the full length of a trench duct with removable cover plates. This practice allows cables to be placed, rather than pulled, into the duct. Before pouring concrete, seal all openings and joints on the cover plates with tape. After the concrete pour, level the top rail of the trench so that the cover plate is flush with the concrete, then install the floor finish trim. TOC Each cover plate must: Search Print Search • Be made of 6.4-mm (¼-in.) flat steel or a material of equivalent strength and rigidity. Find • Weigh 30 kg (65 lb.) or less. Find NOTE: Quarter-inch steel weighs approximately 5 kg (11 lb.) per square foot. • Overlay a rabbet on the adjacent cover (supported by the next cover). • Be equipped with a means for leveling and alignment with the floor’s surface. • Be equipped with tile trim to prevent damage to the finished flooring. • Be fitted with a gasket to prevent water and other liquids from entering the trench. Quit 113 Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Underfloor Duct Systems Chapter 4 - Horizontal Cabling Systems Cover Plates for Trench Ducts, continued Help Typical cover plate dimensions are shown in the following illustration. TOC Figure 4.14: Trench duct on cellular floor Print Cover Plate Cover Plate Search 3 in. 12 in. 8 in. Search * 12 in. * Find Find 3 in. * ** Quit ** *Normally 2 1/2 in. depth. **Width 9 in., 12 in., 18 in., 27 in., 38 in. 3/16 in. to 1/2 in. (Depending on width and application) Cover plates are generally made: In sections 1, 2, or 4 ft. long. Of aluminum or steel. - + NOTE: Multiply inches by 2.54 to convert to centimeters. 114 Underfloor Duct Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Removing Trench Duct Cover Plates Help Building personnel should remove trench duct covers. However, telecommunications personnel may be expected to remove one or two duct covers to expedite a job. TOC Provide and store one cover-lifting device on each floor of the building (preferably in the telecommunications closet). Search Remove trench covers with: Search • Find Suction cups. or • Print Find Quarter-inch eyebolts with threaded holes in the cover. NOTE: Electromagnets may be used, but are not recommended due to their damaging effects when accidentally exposed to magnetic storage media and electronic equipment. Quit Do not use screwdrivers. 115 Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Underfloor Duct Systems Chapter 4 - Horizontal Cabling Systems Removing Trench Duct Cover Plates, continued Help A suction cover plate lifter and a cover plate with threaded eyebolts added are shown in the following illustration. TOC Print Figure 4.15: Cover plate lifter and cover plate Search Search Find - + Find Eye-bolts for Cover Plate Removal Quit - + 116 Underfloor Duct Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Compartments in Trench Ducts Help Supply a dividing partition for any trench that will contain both power and telecommunications cables. Each partition must extend to the underside of the cover plate to assure complete physical and electromagnetic separation of the cabling in compartments which the partition divides. Partitions—which should be adjustable or tack welded into place—must have load-bearing capacity to help support the cover. TOC Print Search Search NOTE: All tack welds must be painted to prevent rusting. For additional cover support, equip trenches that have compartments more than 45 cm (18 in.) wide with adjustable load-bearing supports. Locate the supports: • Along the center line of the compartment. • No more than 45 cm (18 in.) apart. Find Find Quit IMPORTANT: When installing load-bearing supports, anchor the bottom plate of the trench to the concrete beneath it before setting the adjustable screw of the support. Place the support’s anchor adjacent to the point of adjustment. 117 Underfloor Duct Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Enclosing Underfloor Duct in Concrete Help The structural design of a building is usually based on considerations other than the electrical power and telecommunications cabling requirements. The floor plan and type of floor construction should be determined before the underfloor distribution system is considered in detail. TOC Print Search Options for Enclosing Underfloor Duct Search One-level and two-level underfloor duct systems can be enclosed in either the: Find • Structural floor system (i.e., the slab). Find or Quit • Fill placed on top of the slab. In cases where slab-on-grade floor construction (where concrete is placed directly on the soil with no basement or crawl space) is used, give special consideration to maintaining the level of the underfloor duct system. 118 Underfloor Duct Systems Enclosing Duct in the Slab When ducts can be enclosed within the slab, the: Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Help TOC • Weight of the structure is reduced. • Floor system is: Print - Shallower. Search - Stiffer. Search - Less expensive to construct. Find Find Quit 119 Design Guidelines for Underfloor Ducts Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Introduction Design Guidelines for Underfloor Ducts Help It is practical and economical to maintain telecommunications facilities in a raceway system for the life of a commercial building. The information in the following sections will help you decide the type, size, and quantity of underfloor duct needed for a specific installation. TOC NOTE: The recommendations in these sections are influenced by the information in “Avoiding Electromagnetic Interference (EMI)” in this chapter. When designing and installing underfloor duct systems, ensure that the horizontal cables from the horizontal cross-connect in the telecommunications closet to the outlet are no more than 90 m (295 ft.) long. Print Search Search Find Find Quit 120 Design Guidelines for Underfloor Ducts Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Feeder Duct Size Help Feeder ducts range from 49 cm 2 to 57 cm 2 (7.6 in 2 to 8.9 in 2 ) in cross-sectional area (internal space). In theory, a duct in this range can serve an area of approximately 80 m 2 (800 ft 2 ). TOC If it is necessary to serve a floor area with telecommunications outlets placed at regular desk intervals (in 2-m. [6.5-ft.] square modules, for example), take care to provide adequate duct capacity. Use the: Search • Large duct size for distribution ducts, with trench duct for feeder duct. Print Search Find or • Home-run design. Feeder Duct Capacity Measure the cross-sectional area of a feeder duct to determine if its capacity is adequate for the area it will serve. As a general rule, 6.5 cm 2 (1 in 2 ) of crosssectional area is required in a duct for each 10 m 2 (100 ft 2 ) of usable floor space that it serves. This ratio, which applies to both feeder duct and distribution duct, is generally considered adequate to serve up to three telecommunications outlet/connectors per work area. Find Quit 121 Design Guidelines for Underfloor Ducts Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Feeder Duct Capacity, continued Help To determine the usable floor space that a feeder duct can serve, follow the steps listed below. TOC Step Determining the Floor Space that a Feeder Duct Can Serve Print Example m, cm (ft., in.) Search 1 Measure the inside height of the duct. 5.1 cm (2 in.) 2 Measure the inside width of the duct. 10.2 cm (4 in.) Search 3 Multiply the height by the width to determine the cross-sectional area of the duct. 5.1 cm x 10.2 cm 52.0 cm 2 (2 in.) (4 in.) (8 in 2 ) Find 4 To determine the usable floor space that the duct can serve, multiply its cross-sectional area by 1.54 m 2 /cm 2 (10 m 2 /6.5 cm 2 ) or 100 ft 2 /in 2 . (See “Determining Duct Size” in this chapter.) 2 52.00 cm x 1.54 m 2 /cm 2 80.0 m 2 Find 2 (8 in ) (100 ft 2/in 2) (800 ft 2 ) NOTE: Select a different size feeder duct when the cross-sectional area indicated by these steps is too large or too small for the floor space ser ved by the duct. Quit 122 Design Guidelines for Underfloor Ducts Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Distribution Duct Sizes Help Standard distribution ducts range from 21.3 cm 2 to 25.2 cm 2 (3.3 in 2 to 3.9 in 2 ) in cross-sectional area. Use larger distribution ducts when serving a floor area between 18 m and 24 m (60 ft. and 80 ft.) long. TOC Plan for one individual work area per 10 m 2 (100 ft 2 ) of usable floor space (this value takes into account space for corridors and other common traffic areas) and a minimum capacity of three cables per individual work area. For distribution ducts, the guideline of 6.5 cm 2 (1 in 2) of cross-sectional area per 10 m 2 (100 ft 2) of usable floor space should suffice. Based on this guideline, a 21.3 cm 2 (3.3 in 2) distribution duct should be capable of serving a usable floor space of 2 m (6 ft., 6 in.) wide by 16.5 m (54 ft.) long (or 33 m 2 [330 ft 2]). Distribution ducts are available in the sizes listed in the following table. Print Search Search Find Find Quit Table 4.7: Duct sizes Duct Size Range of Cross-Sectional Areas . . . Standard 21 cm 2 to 25 cm 2 (3.3 in 2 to 3.9 in 2 ) Large 49 cm 2 to 57 cm 2 (7.6 in 2 to 8.9 in 2 ) 123 Design Guidelines for Underfloor Ducts Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Insert Duct Sizes Help The following illustration shows documentation on a typical ellipsoid insert duct and a conventional insert duct. TOC Print Figure 4.16: Insert ducts Search Search B Ellipsoid Insert Duct A "A" (Inside) 7 19/32 in. 6 19/32 in. 7 3/32 in. 6 11/32 in. 6 15/32 in. 1 1 1 1 1 "B" (Inside) 7/32 in. 11/32 in. 7/32 in. 11/32 in. 9/32 in. Conventional Insert Duct Find Manufacturer-Recommended Usable Total Capacity Capacity (50% Square Inches) (Square Inches) 4.60 9.2 4.50 9.0 4.45 8.9 4.29 8.58 4.21 8.41 Find Quit One Cell Two Cells - + Three Cells NOTE: Multiply inches by 2.54 to convert to centimeters; multiply square inches by 6.45 to convert to square centimeters. 124 Design Guidelines for Underfloor Ducts Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Space Requirements for Trench Ducts Help Space requirements for trench ducts are listed in the following table. TOC Table 4.8: Space requirements Print Type of Space Needed Dimensions Interconnection openings between trench and distribution duct (or the cell below) 6.3 cm by 13 cm (2½ in. by 5 in.) minimum Usable depth 3.2 cm (1¼ in.) minimum Find Usable depth for telecommunications service (regardless of actual depth) 6.3 cm (2½ in.) maximum Find Search Search Quit 125 Design Guidelines for Underfloor Ducts Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Slab Thickness Requirements for Enclosing Duct Help When duct is enclosed in the slab, the slab must meet the thickness requirements listed in the following table. TOC Print Table 4.9: Thickness requirements Type Of Duct System Required Slab Thickness Search One-level 13 cm (5 in.) Search Two-level 18 cm (7 in.) Feeder beam concept (See the illustration in “Intersecting Feeder and Distribution Ducts” in this chapter.) 18 cm (7 in.) Find Find Quit 126 Design Guidelines for Underfloor Ducts Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Advantages and Disadvantages of Enclosing Duct with Fill Help Using the fill to enclose the underfloor duct system has the following advantages and disadvantages: TOC Print Table 4.10: Enclosing duct with fill Advantages Disadvantages Search • • Search • • The type of floor system used is independent of the underfloor system design. Ducts can be placed in any direction. The extra slab thickness adds more fire resistance. However, the required 13 cm (5 in.) minimum thickness for ducts probably provides a two-hour fire-resistance rating without fill. Additional dead weight is added to the structure, thereby increasing foundation loads. Find Find • • The additional material contributes nothing to the strength of the floor. Quit The height of the building is increased because of the additional floor thickness. 127 Design Guidelines for Underfloor Ducts Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Advantages and Disadvantages of Enclosing Duct with Fill, continued Help TOC Table 4.10: Enclosing duct with fill, continued Print Advantages Disadvantages • • Wire mesh in the fill costs extra. • Fill placement is an extra construction operation. An inch of fill costs more than an extra inch of monolithic construction. Some contractors prefer a fill. It relieves them of: - Close tolerances in finishing the slab. - Difficulties with construction scheduling. Search Search Find Find Quit 128 Design Guidelines for Underfloor Ducts Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Fill Thickness Requirements for Enclosing Duct Help When a duct is enclosed with the fill, the fill must meet the thickness requirements listed in the following table. TOC Print Table 4.11: Thickness requirements Type Of Duct System Required Fill Thickness Search One-level 7 cm (2¾ in.) Search Two-level 11 cm (4¼ in.) Feeder duct depressed into the slab 7 cm (2¾ in.) Find Find Quit 129 Design Guidelines for Underfloor Ducts Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Fill Thickness Requirements for Enclosing Duct, continued Help Figure 4.17: Feeder duct in slab TOC Distribution Ducts A A Feeder Duct NOTE: When possible, depress the bay containing the feeder beam. Keep ducts in the center of the bay to avoid interfering with the structural steel of the joists. Print Search Search Find Find Quit - Distribution Duct Feeder Ducts Fill + Joist - + 130 Telecommunications Closet Considerations (for Underfloor Ducts) Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Telecommunications Closet Considerations (for Introduction Underfloor Ducts) All feeder and distribution ducts must be physically linked to a telecommunications closet either directly or through no more than one feeder duct. Ensure that the closet is: • Large enough for the required quantity of feeder ducts. • Located centrally within the zone. Telecommunications closets must be as close as possible to the floor areas they serve in order to provide adequate feed. NOTE: For information on the termination of horizontal pathways in the telecommunications closet, see Chapter 6, “Telecommunications Closets and Rooms.” Help TOC Print Search Search Find Find Quit 131 Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Telecommunications Closet Considerations (for Underfloor Ducts) Chapter 4 - Horizontal Cabling Systems Telecommunications Closets in the Core of a Multistory Building Elevator Power Closet TOC Telecommunications Closet Print P P T P T P T P T P T P T P T T T P T T P Search T P T P T P T P T P Power Closet P The following illustration shows telecommunications closets located in the core area of a multistory building. Telecommunications Closet Help Search Find Figure 4.18: Typical underfloor duct layout in a multistory building Find = = P = T = Underfloor Distribution Ducts Underfloor Feeder Ducts Power Duct Telecommunications Duct - P P T P T P T P T P T P T T P T T T P T P T P T P T P T P P T P Quit + 132 Telecommunications Closet Considerations (for Underfloor Ducts) Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Telecommunications Closet Occupying One-quarter of a Floor Help The following illustration shows a telecommunications closet occupying onequarter of a typical floor. TOC NOTE: The following view is similar to the lower right quarter of the floor plan on the previous page. Divide feet by 3.28 to convert to meters. Figure 4.19: Telecommunications closets - ¼ of a floor plan Print Search To Telecommunications Closet C L P of Building Search T P T P Find 25 ft. T P T P Find T P Quit T P T P 25 ft. T P T P - T 25 ft. C L of Building 25 ft. + 25 ft. P = Power Duct T = Telecommunications Duct 133 Telecommunications Closet Considerations (for Underfloor Ducts) Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Terminating Ducts in Telecommunications Closets Help Ducts that enter the closet must terminate in either a slot or an elbow. Choose the method for terminating ducts in telecommunications closets according to the guidelines in the following table. TOC NOTE: A step-by-step design procedure for terminating underfloor duct is given in “Designing Underfloor Duct for Telecommunications Systems” in this chapter. Search Print Search Find Find Quit 134 Telecommunications Closet Considerations (for Underfloor Ducts) Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Terminating Ducts in Telecommunications Closets, continued Help Table 4.12: Guidelines for terminating ducts TOC If Ducts Enter the Telecommunications Closet and . . . Then... Print Do not pass within the closet floor slab Terminate the ducts in a floor trench 8-15-cm (3-6-in.) wide. NOTES: • Do not make the length of the trench less than the overall width of the feeder duct band that terminates in it. • Close the end of the ducts with removable caps. Pass within the closet floor slab Search Search Find Find Quit Use duct elbow fittings to terminate the ducts at the plywood-lined wall. NOTE: Terminate the elbow 2.5-7.5 cm (1-3 in.) above the finished floor. 135 Design Procedure for an Underfloor Duct System Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Designing Underfloor for Ductan forUnderfloor Telecommunications Systems Design Procedure Duct System Help The layout of the feeder ducts and distribution ducts is determined by the present and planned future uses of the floor area they serve. The following steps show the procedure for designing the spacing and size of underfloor duct systems for telecommunications facilities. TOC Print Search Step Designing Underfloor Duct for Telecommunications Systems 1 Determine the total usable floor area (hallways included). 2 Divide the floor area (m 2 [ft 2 ]) by 1.54 m 2 /cm 2 (100 ft 2 /in 2 ) to get the total feeder duct area (cm 2 [in 2 ]) required for telecommunications. Floor area (m 2) ÷ 1.54 (m 2/cm 2) Total feeder duct area (cm 2) Floor area (ft 2) ÷ 100 (ft 2/in 2) Total feeder duct area (in 2) Search Find Find Quit 136 Design Procedure for an Underfloor Duct System Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Designing Underfloor Duct for Telecommunications Systems, continued Step Designing Underfloor Duct for Telecommunications Systems 3 Determine the minimum number of feeder ducts required by dividing the total feeder duct area required by the crosssectional area of one feeder duct. Total feeder duct area (cm2) Total feeder duct area (in2) ÷ Area per feeder duct (cm2) ÷ Area per feeder duct (in2) Minimum no. of feeder ducts Minimum no. of feeder ducts NOTE:Since building layouts do not always permit all feeders to be filled to their maximum recommended capacity, additional feeders may be needed. The additional quantity required will depend on the floor plan and on the location of the telecommunications closet. 4 Help TOC Print Search Search Find Find Quit Select a spacing for the distribution duct. Use the chart in “General Rule for Spacing Ducts” in this chapter. 137 Design Procedure for an Underfloor Duct System Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Designing Underfloor Duct for Telecommunications Systems, continued Step Designing Underfloor Duct for Telecommunications Systems 5 Establish subzones that best use the distribution design. 6 Establish telecommunications zones with usable floor areas of greater than 1,000 m 2 (10,000 ft 2 ) to be served by each closet. 7 Divide the zones into strips equal in width to the spacing of the distribution ducts. NOTE: Distribution ducts typically are placed between 45 cm-61 cm (18 in.-24 in.) from the outside wall. However, the floor area that they ser ve extends to the wall. For further information, see “General Rule for Spacing Ducts” in this chapter. Help TOC Print Search Search Find Find Quit 138 Design Procedure for an Underfloor Duct System Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Designing Underfloor Duct for Telecommunications Systems, continued Step Designing Underfloor Duct for Telecommunications Systems 8 Compute the maximum allowable length of the distribution duct. NOTE: Base the calculation on the telecommunications requirements of 6.5 cm 2 (1 in 2 ) of cross-sectional duct area per 10 m 2 (100 ft 2 ) of usable floor space. Help TOC Print Search Search Find 1.54 (m 2/cm 2) x Area of 1 duct (cm 2) = Allowable length of Spacing of ducts (m) distribution duct (m) Find or Quit 100 (ft 2/in 2) x Area of 1 duct (in 2) = Allowable length of Spacing of ducts (ft.) distribution duct (ft.) 139 Design Procedure for an Underfloor Duct System Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Designing Underfloor Duct for Telecommunications Systems, continued Step Designing Underfloor Duct for Telecommunications Systems 9 Determine if the length found in Step 8 is less than the planned distance from the end of the distribution duct to the feeder duct. If it is, select a larger duct size or closer spacing and recalculate. NOTE: The distribution duct system must be designed so that horizontal cables extending from the horizontal cross-connect in the telecommunications closet to the outlet are not more than 90 m (295 ft.) long (including slack and service loops). Help TOC Print Search Search Find Find Quit A procedure to determine the allocation of feeder ducts to distribution ducts appears in ANSI/TIA/EIA-569-A (in Canada, see CSA T530). 140 Design Procedure for an Underfloor Duct System Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems General Rule for Spacing Ducts Help Determine the spacing for telecommunications distribution ducts by the following steps. TOC Step 1 General Rule For Spacing Ducts Print Place distribution ducts parallel to the longest outside walls. ( This reduces the length of the feeder ducts.) Distribution duct runs that are adjacent to exterior buildings should be located 45 cm-61 cm (18 in.-24 in.) from the outside walls or column lines. Search NOTE: The layout must allow for work area cables to exit the duct under the desks. Layouts for desks are less difficult if the design locates distribution duct parallel to the outside walls. (See “Telecommunications Closets in the Core of a Multistory Building” in this chapter.) Find Search Find Quit 141 Design Procedure for an Underfloor Duct System Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems General Rule for Spacing Ducts, continued Help Step TOC 2 General Rule For Spacing Ducts Locate and center the distribution duct runs 1.5 m-1.8 m (5-6 ft.) apart, or in the center of each building module (space between joists), provided that the spacing does not exceed 1.8 m (6 ft.). NOTE: 1.5 m (5 ft.) spacing provides the maximum flexibility per unit of floor area over the life of the building. Increased spacing: • Beyond 1.8 m (6 ft.) dramatically restricts the system’s flexibility. Print Search Search Find Find Quit and • Does not offer dramatic cost reductions within normal design limits. 142 Design Procedure for an Underfloor Duct System Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems General Rule for Spacing Ducts, continued Help Step General Rule For Spacing Ducts TOC Continue with Step 2 for the entire usable floor, regardless of the proposed or intended use of a particular area. Print 3 NOTE: Experience shows that building-use plans are subject to numerous changes over the life of a building. Search Search Find Find Quit 143 Design Procedure for an Underfloor Duct System Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Example of Duct Capacity Help In the following illustration, the capacity is sufficient in the area to the right of the feeder ducts. This is because the length of the duct extending from the feeder is less than 20 m (66 ft.). TOC Figure 4.20: Duct capacity Search Print To Telecommunications Closet C L P of Building T P T P Find 25 ft. T P NOTE: Only onequarter of the total floor is shown. Divide feet by 3.28 to convert to meters. Search T P Find T P Quit T P T P 25 ft. T P T P T 25 ft. C L of Building 25 ft. 25 ft. Example: 100 x 3.3 sq. in. 5 ft. = 66 ft. - + P = Power Duct T = Telecommunications Duct 144 Design Procedure for an Underfloor Duct System Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Example of Duct Capacity, continued Help Under a normal design, 6.5 cm 2 (1 in 2 ) of duct is provided for every 10 m 2 (100 ft 2 ) of floor area. In the preceding figure, the length of the building to the left of the feeder ducts is approximately 26 m (85 ft.) because of the offcenter location of the telecommunications closet. TOC Moving the telecommunications closet to the center line of the building would give the floor an almost perfect balance. However, the telecommunications closet location is usually determined by other factors, such as the locations of : • Elevators. • Stairs. • Rest rooms. Print Search Search Find Find Quit If the telecommunications closet location cannot be changed, add the required number of feeder and distribution ducts to adequately feed the area ser ved. 145 Design Procedure for an Underfloor Duct System Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Allocating Feeder Duct to Distribution Duct Help Follow the steps in the procedure below to allocate feeder duct to distribution duct. TOC Step 1 2 Allocating Feeder Duct To Distribution Duct Print Write a fraction, using the number of : Search • Feeder ducts required to serve a floor area as the numerator. Search • Distribution ducts served as the denominator. Reduce the fraction to a ratio of small whole numbers, such as: Find • 1/1, 1/2, 1/3, etc. Find • 2/3. Quit • 3/4 (use this ratio only as a last resort). If the fraction cannot be reduced to one of the ratios listed above: • Deduct 1, 2, or 3 from the number of distribution ducts (i.e., the denominator) and reduce the fraction to a simple ratio ( These ducts are treated as a separate zone and served by additional feeders.) 146 Design Procedure for an Underfloor Duct System Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Allocating Feeder Duct to Distribution Duct, continued Help Step Allocating Feeder Duct To Distribution Duct TOC 2, cont. or • Print Add 1 to the number of feeder ducts (the numerator) and reduce the fraction to a simple ratio. If the fraction cannot be reduced to one of the ratios listed at the beginning of Step 2 when either option is used separately, use both options together and try to reduce the fraction again. If a duct is deducted, treat it as a separate unit served by additional feeders. 3 If the numbers of feeder and distribution ducts are nearly equal, increase the feeder ducts by 1, 2, or 3 so they are equal. (It is economical to do this.) Search Search Find Find Quit NOTE: It is usually more costly to add handholes than feeder ducts. As a rule of thumb, a handhole costs the equivalent of 3 m (10 ft.) to 12 m (40 ft.) of feeder duct, depending on the size and type. 147 Design Procedure for an Underfloor Duct System Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Using Preset Inserts Help Always provide distribution duct with preset inserts at regular intervals. These inserts: TOC • Have a 5-cm (2-in.) nominal inside width. Print • Are factory installed (or equivalent). Search • Have a center spacing of 61 cm (24 in.) or less. Generally, preset inserts are available in 1.3-cm (½-in.) increments from 2.2 cm ( 7 / 8 in.) - 7.6 cm (3 3 / 8 in.) in height. The recommended height is 2.5 cm (1 in.) 6.4 cm (2½ in.) maximum. If the preset inserts are higher than 6.4 cm (2½ in.), derate the capacity of the duct. Search Find Find Quit 148 Design Procedure for an Underfloor Duct System Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Using Preset Inserts, continued Help Level duct runs with preset inserts so that the top of the insert is 3 mm (0.125 in.) below the finished pour. Place screws or other types of markers to identify the duct runs: TOC • At each duct end. • On either side of permanent partitions. • In the first insert adjacent to access units. • At intervals of approximately 15 m (50 ft.). NOTE: Consider the cost of placing initial floor fittings (both afterset and preset inserts). In most cases, it is more economical to provide preset inserts, even when the cost of covering locations where they may not be used is included. If necessary to order aftersets, a maximum of 10 percent of the original presets should be ordered. Print Search Search Find Find Quit 149 Design Procedure for an Underfloor Duct System Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Determining Insert Spacing Help If the standard insert spacing of 0.6 m (2 ft.) is not adequate for a custom design, spacing may be determined by simply dividing the building module spacing by the number of inserts needed per module. TOC For example, in a 1.5-m (5-ft.) module, the insert spacing can be: Search Print • 150 cm (60 in.) ÷ 2 = 75 cm (30 in.) spacing (too long). • 150 cm (60 in.) ÷ 3 = 50 cm (20 in.) spacing (good). • 150 cm (60 in.) ÷ 4 = 38 cm (15 in.) spacing (better). Find • 150 cm (60 in.) ÷ 5 = 30 cm (12 in.) spacing (very good, but probably too expensive). Find The recommended spacing is 38 cm (15 in.) or 50 cm (20 in.), with the inserts an equal distance from the module lines. Quit Search 150 Design Procedure for an Underfloor Duct System Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Using Afterset Inserts Help Provide access to blank cells by core drilling through the concrete and cutting through the top surface of the cell. Tightly fasten afterset inserts to the duct, cell, or hole. The insert must: TOC • Provide a smooth surface at the edge of the metal for pulling in cables. • Have at least a 5-cm (2-in.) nominal inside measurement. • Be designed to be capped flush with the concrete floor and left in place for future use. Print Search Search Find Find Quit 151 Design Procedure for an Underfloor Duct System Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Performing a Final Design Check Help After designing an underfloor duct system, perform a final design check by the following steps. TOC Step Performing A Final Design Check Print 1 Check the cross-sectional area of each feeder duct. Search 2 Determine if it is adequate for the area it serves. Search NOTE: 3 The cross-sectional area of the duct, in square centimeters (square inches) multiplied by 1.54 m 2 /cm 2 (100 ft 2 /in 2 ) must be greater than or equal to the floor area, in square meters (square feet) that it serves. Check the spacing requirements of the feeder ducts. Find Find Quit 152 Design Procedure for an Underfloor Duct System Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Performing a Final Design Check, continued Help Step TOC 4 Performing A Final Design Check Determine if there are any obstructions or length limitations that may affect the layout and installation of the required ducts. NOTE: The maximum distance between any location on a telecommunications distribution duct and the nearest junction box must not exceed 18 m (60 ft.). In layouts where the distribution runs exceed 18 m (60 ft.), consider adding additional feeder ducts to interconnect the telecommunications distribution ducts and reduce the pull distance. Print Search Search Find Find Quit The underfloor duct system shall be designed and installed such that horizontal cables extending from the horizontal cross-connect in the closet to the outlet are not more than 90 m (295 ft.) long. 5 Check the size of the telecommunications closets (See Chapter 6). 153 Designing a Two-level Duct System Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Introduction Help The design of an underfloor duct system depends on the: TOC Designing a Two-level Duct System • Floor space to be occupied. • Location of telecommunications closets. For telecommunications use in most buildings, a two-level underfloor duct system is: • Practical. • Useful. • Economical. • Compatible with reinforced concrete construction. Print Search Search Find Find Quit 154 Designing a Two-level Duct System Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Using a One-way Metal Pan Joist Floor Design Help One method for installing a two-level underfloor duct system in a concrete floor is shown in the following illustration which shows a distribution duct system in a one-way metal pan joist floor design. TOC NOTE: This is one of the most economical and frequently used methods for office floor construction. Search Figure 4.21: Distribution duct system Search PT PT PT PT PT PT PT Print Find Find NOTE: See following figures for view details. Quit A-2 A-3 A-3 A-2 A-1 - + A-1 155 Designing a Two-level Duct System Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Positioning Distribution Duct in the Slab Help The following illustration shows the position of the distribution duct in the slab. The slab thickness required is 12.7 cm (5 in.). ( The section shown is Section A1-A1 from the illustration above.) TOC Figure 4.22: Distribution duct in the slab Search Print Search 2 in. Concrete Duct Insert Find 5 in. Find 1.375 in. Duct Concrete Joist - Depth Quit + Rebars NOTE: Multiply inches by 2.54 to convert to centimeters. 156 Designing a Two-level Duct System Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Intersecting Feeder and Distribution Ducts Help In areas where feeder and distribution ducts intersect, both levels of a twolevel system require a 17.8-cm (7-in.) thickness, as shown in the following illustration. Section A2-A2 from the illustration in “Using a One-Way Metal Pan Joist Floor Design” in this chapter is shown. TOC Print Search Figure 4.23: Two-level system Search Duct Insert Find 5 in. Distribution Ducts Find Feeder Ducts D D-2 in. Quit Joist Rebars - + NOTE: Multiply inches by 2.54 to convert to centimeters. 157 Designing a Two-level Duct System Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Intersecting Feeder and Distribution Ducts, continued Help The area of the feeder duct (about five percent of the total floor area) generally requires: TOC • Eliminating one or more joists. Print • A special design for the adjacent joists. Search NOTE: Use plywood forms to: Search • Case the “feeder beam” area. Find • Facilitate accurate leveling of junction boxes. Find Quit 158 Designing a Two-level Duct System Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Feeder Beams Help The following illustration shows a section through the feeder beam at the column lines (i.e., where the feeder beam intersects the floor girder). Section A3-A3 from the illustration in “Using a One-Way Metal Pan Joist Floor Design” in this chapter is shown. TOC NOTE: For a more economical floor system, make the depth of the girder the same as the joist. Figure 4.24: Feeder beam Distribution Ducts Print Search Search Find Duct Insert Find Rebars 7 in. Feeder Ducts Quit 2 in. Column - NOTE: Multiply inches by 2.54 to convert to centimeters. + 159 Designing a Two-level Duct System Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Feeder Beams, continued Help The girder is actually a T-beam. The placement of ducts through the girder does not affect its flexural capacity. However: TOC • Give special attention to the shear. Print • Provide a minimum of stirrups in this area. Search NOTES: • Ducts do not interfere with girder reinforcement. • Spacing between ducts is usually 2.5 cm (1 in.), with 2.5 cm (1 in.) - 4 cm (1½ in.) of cover. Verify the use of this spacing with local codes. Search Find Find Quit 160 Cellular Floor Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Introduction Help Cellular floor systems are made up of two distinct components: TOC Cellular Floor Systems • Distribution cells. • Feeder ducts, trench ducts, or a combination of the two. The distribution cells in the deck of a cellular steel floor provide one level of a two-level system. Distribution cells may be made of steel or concrete, depending on the floor material. Print Search Search To complete a two-level system, it is necessary to add only the feeder ducts. Either enclosed feeder or trench ducts may be used to complete the system by feeding it from the telecommunications closet to the distribution ducts. Find The typical depth of the concrete pour for: Quit • Cellular steel construction is 6.4 cm (2.5 in.). • Cellular concrete construction is 3.8 cm (1.5 in). Find Because feeders are contained within the pour, the number of feeder ducts possible and the width of the trench ducts depend on this depth. 161 Cellular Floor Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Introduction, continued Help Steel cellular construction is the preferred type of cellular floor. Steel cellular floors have a greater capacity and are easier to install and use than concrete cellular floors. When concrete cells are used, follow the guidelines and restrictions in ANSI/TIA/EIA-569-A (in Canada, refer to CSA T530). TOC Refer to ANSI/NFPA 70, Articles 356 and 358 (in Canada, CSA C22.1, Sections 12-1800 through 12-1820). Print Search Search Find Find Quit 162 Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Cellular Floor Systems Chapter 4 - Horizontal Cabling Systems Examples of Cellular Floor Systems Help The following illustrations show cross-sections of cellular floor systems. TOC The following illustration shows a cellular floor system which uses: • Trench ducts for telecommunications services. • Enclosed feeder ducts for power service. Search Figure 4.25: Cross-section of cellular plan system CAUTION: In steel cellular floor construction, do not use a feeder from below the deck (e.g., a conduit to a cell). This design is inflexible and violates many municipal building codes. Telecommunications Header Duct with Removable Cover Plates Print Telecommunications Service Fitting Power Header Duct Power Service Fitting Search Find Find Quit Telecommunications Cell - Power Cell + Cellular Steel Floor 163 Cellular Floor Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Examples of Cellular Floor Systems, continued Help The following illustration shows another view of a cellular floor system fed by a trench duct. TOC Figure 4.26: Cellular floor system (trench duct) Print Search Search Find Find Quit - + 164 Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Cellular Floor Systems Chapter 4 - Horizontal Cabling Systems Typical Cellular Arrangement A typical steel framing arrangement for a cellular floor with feeder duct is shown in the following illustration. Help TOC Cellular Steel Floor (1 Unit "Closed" Cells) Print 6 ft. Telecommunications Header Ducts 4 Bays at 30 ft. = 120 ft. Service Core Search A Figure 4.27: Typical cellular arrangement Power Header Duct 2 ft. A P Cellular Steel Floor (3 Units "Open" Cells) 35 ft. 30 ft. Search T T Find Find 35 ft. 100 ft. Quit Concrete NOTE: Divide feet by 3.28 to convert to meters. - + Beam Cellular Steel Floor Typical Section Through Beam Telecommunications Fitting After-Set Insert with Abandoning Cap After-Set Insert 165 Cellular Floor Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Standard Cellular Steel Floor Modules Help Cellular steel floor modules are available in: TOC • Two-cell, three-cell, and four-cell configurations. • Depths of 3.8 cm (1½ in.) to 7.6 cm (3 in.). Four commonly used cellular steel floor decks are shown in the following chart. Although modules with different dimensions can be found, using a standard module is the most economical choice. NOTE: The overall widths and cell spacing of the modules below are standard. Profile dimensions may var y slightly, depending on the manufacturer. Print Search Search Find Find Quit 166 Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Cellular Floor Systems Chapter 4 - Horizontal Cabling Systems Standard Cellular Steel Floor Modules, continued Help Table 4.13: Cellular floor steel decks TOC Size Number Of Cells 3.8 cm (1½ in.) deep by 61 cm (24 in.) wide Four Print Search Search 24 in. 1 3 /2 in. 6 in. Find 1 1 /2 in. - 2 in. + Find Quit NOTE: The area of the shaded cell is 34 cm 2 (5.25 in 2 ). (Multiply inches by 2.54 to convert to centimeters.) 167 Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Cellular Floor Systems Chapter 4 - Horizontal Cabling Systems Standard Cellular Steel Floor Modules, continued Help Table 4.13: Cellular floor steel decks, continued TOC Size Number of Cells 4.1 cm (1 / 8 in.) deep by 61 cm (24 in.) wide Print Three 5 Search 24 in. Search 1 5 /8 in. Find 8 in. 5 1 /8 in. - + 5 1 /8 in. Find Quit NOTE: The area of the shaded cell is 54 cm 2 (8.3 in 2 ). (Multiply inches by 2.54 to convert to centimeters.) 168 Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Cellular Floor Systems Chapter 4 - Horizontal Cabling Systems Standard Cellular Steel Floor Modules, continued Help Table 4.13: Cellular floor steel decks, continued TOC Size Number of Cells 7.6 cm (3 in.) deep by 61 cm (24 in.) wide Three Print Search Search 24 in. 5 Find 5/ 8 in. 8 in. Find 3 in. - + 1 2 /8 in. Quit NOTE: The area of the shaded shell is 110 cm 2 (17 in 2 ). (Multiply inches by 2.54 to convert to centimeters.) 169 Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Cellular Floor Systems Chapter 4 - Horizontal Cabling Systems Standard Cellular Steel Floor Modules, continued Help Table 4.13: Cellular floor steel decks, continued TOC Size Number of Cells 7.6 cm (3 in.) deep by 46 cm (18 in.) wide Three Search Search 18 in. 3 3/ 8 in. Print Find 6 in. Find 3 in. - + 1 2 /8 in. Quit NOTE: The area of the shaded cell is 65 cm 2 (10 in 2 ). (Multiply inches by 2.54 to convert to centimeters.) 170 Cellular Floor Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Components of a Closed Cellular Unit Help As the preceding illustrations show, a closed cellular unit is made of two sheets of steel welded together to form the: TOC • Roll-formed (corrugated) top. Print • Flat-sheet bottom. Search It is possible to have any combination of closed and open cellular units to satisfy the requirements of: • Area. • Size. • Number and location. Closed cells can be provided: • Search Find Find Quit At 15-cm or 20-cm (6-in. or 8-in.) centers across the entire building width. or • In groups of three or four on any module with 61-cm or 46-cm (24-in. or 18-in.) spacing, depending on the floor deck selected. In evaluating and comparing modules for use, it is important to include the effect of closed cells on structural layout and cost. 171 Design Considerations for Cellular Floors Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Introduction Help Cellular floor construction: TOC Design Considerations for Cellular Floors • Serves as a structural floor. • Provides a distribution system for telecommunications and power. Because of their dual function, cellular floors make the structural design of a building more economical. See “Avoiding Electromagnetic Interference (EMI)” in this chapter. NOTE: When the cells in cellular floor modules provide different crosssectional areas, allocate the largest cell for telecommunications and the smallest cell for electrical power. Print Search Search Find Find Quit 172 Design Considerations for Cellular Floors Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Design Considerations Help When designing a cellular floor system, it is necessary to consider the: TOC • Usable floor area to be served by the cells. • Size of the cells. • Number and location of the cells. Because the location of the feeder ducts affects the structure of the building, it is important to coordinate cellular-floor planning with the structural engineer. Print Search Search Find Find Quit 173 Design Considerations for Cellular Floors Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Cellular Floor Capacity Help Determining the required capacity of the distribution system is one of the first concerns in designing a building. It is essential to integrate the: TOC • Layout of the distribution system. Print and Search • The design of the structural floor and supporting members. For telecommunications systems in a cellular floor, the capacity requirements for cells and feeders are the same as the requirements for the distribution and feeder ducts of an underfloor duct system. For details on underfloor duct capacity, see the following sections in this chapter: • “Sizing of Horizontal Pathways” • “Feeder Duct Size” • “Feeder Duct Capacity” • “Distribution Duct Sizes” Search Find Find Quit 174 Design Considerations for Cellular Floors Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Providing Sufficient Cells Help In most office buildings, sufficient cells for underfloor services can be provided by: TOC • Locating cellular sections on 1.2-m or 1.5-m (4-ft. or 5-ft.) centers. Print • Using a 50-percent blend of cellular and non-cellular underfloor duct sections. Search Search Find Find Quit 175 Service Fittings for Underfloor or Cellular Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Introduction Service Fittings for Underfloor or Cellular Systems Help Before installing work area telecommunications equipment, perform the preparatory steps in the following table. TOC Step Preparing To Install Work Area Equipment 1 Mark and drill outlet holes. 2 Install: • Conduits. • Sleeves. • Locking devices. • Floor fittings. 3 Place carpets or floor tiles. 4 Make junction boxes accessible through the carpeting. 5 At each work area equipment location, install: Print Search Search Find Find Quit • Locking devices. • Service fittings. NOTE: Service fittings are also referred to as floor outlet fittings. 176 Service Fittings for Underfloor or Cellular Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Sizes of Service Fittings Help Service fittings (i.e., floor outlet fittings) are available in a variety of : TOC • Sizes (to conceal connecting hardware). • Shapes and finishes (to match the aesthetics of the building). Print The following table describes the general sizes of fittings available. Search Table 4.14: General sizes of fittings Search A Service Fitting That Is . . . Will Accommodate . . . Small A minimum of two, 4-pair UTP outlets. Medium • Large Outlets to support more than two horizontal cables per individual work area. • Connecting devices for key-type telephones and some small attendant telephones. • • Outlets for multiple work areas. Large attendant telephones and consoles. Find Find Quit 177 Service Fittings for Underfloor or Cellular Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Dedicated In-floor Service Fittings Help Dedicated in-floor service fittings: TOC • Are completely immersed in the floor. • May be preset or afterset. This type of fitting can be readily adapted to either a cellular or a non-cellular underfloor duct system. It requires at least 6.4 cm (2½ in.) of concrete on top of the raceway. NOTE: Combined ser vice fittings (i.e., those that contain both telecommunications cabling and electrical power) must be fully partitioned. Print Search Search Find Find Quit 178 Service Fittings for Underfloor or Cellular Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Dedicated In-floor Service Fittings, continued Help The illustration below shows a suggested layout for dedicated in-floor service fittings (staggered module system). TOC Print Building Bay 28 ft. Figure 4.28: Dedicated in-floor ser vice fittings (staggered module system) Building Module Search Building Module Search Find NOTE: Multiply inches by 2.54 to convert to centimeters. Divide feet by 3.28 to convert to meters. Find Building Bay 28 ft. Quit Building Module Line Cell of Duct to Feeder - + 179 Service Fittings for Underfloor or Cellular Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Advantages of Dedicated In-floor Service Fittings Help Using dedicated in-floor fittings: TOC • Allows for placement of different services in a combined fitting. • Conceals all plugs and connecting devices out of sight and below the floor level. • Provides complete flexibility and accessibility for office landscape layouts (and may be used for conventional layouts). • Allows easy deactivation and/or activation (even in carpeted areas) because fittings are reusable. • Eliminates inserts, both preset and afterset. Print Search Search Find Find Quit 180 Service Fittings for Underfloor or Cellular Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Designing for In-floor Fittings Help Determine the requirements for in-floor fittings during the initial design stage. When using the staggered module system, the requirements usually follow those of the building module. (See “Dedicated In-Floor Service Fittings” in this chapter.) TOC Print Search Using Preset Fittings Place all of the preset fittings before the concrete is poured. NOTE: Exposed cables from outlets not covered by desks may be protected by other office furniture or planters. Search Find Find Quit 181 Service Fittings for Underfloor or Cellular Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Using Afterset Fittings Help If afterset fittings are to be used, the places where they will be installed must be filled with a removable material before the concrete is poured. Use blocks of a material which can withstand the pressure of the floor (e.g., foam, wood). TOC To install afterset fittings, follow the steps in the following table. Search Step 1 Installing Afterset Fittings Chip out the block of material where the in-floor fitting will be installed. 2 Grout in the fitting. 3 Bond the fitting to the metallic raceway. Print Search Find Find Quit 182 Service Fittings for Underfloor or Cellular Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Fitting Housing Size Help Ensure that the fitting housing is large enough to: TOC • House all connectors. • Permit the telecommunications cable to be routed without damage or violation of bend radius requirements. NOTE: The minimum recommended fitting housing size is 10 cm by 18 cm (4 in. by 7 in.). If electrical power is one of the services in a combined fitting, be sure that the fitting is fully partitioned. Print Search Search Find Find Quit 183 Service Fittings for Underfloor or Cellular Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Fitting Openings Help Ensure that the: TOC • Bottom opening of a fitting (into the cell or duct below) is: – Grommet-lined to avoid mechanical damage to the cable. – At least 8 cm (3 in.) in diameter. NOTE: The recommended size for a rectangular bottom opening is 5 cm by 8 cm (2 in. by 3 in.). • Top opening of the fitting is large enough for: – Inserting hands. – Bending cables. Print Search Search Find Find Quit NOTE: The recommended size for the top opening is 9 cm by 15 cm (3½ in. by 6 in.) or equivalent. 184 Carpet Openings Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Introduction Help In carpeted areas, all junction boxes must be accessible. Carpet openings which are cut when the carpet is installed: TOC • Ensure accessibility. Print and Search Carpet Openings • Can be made practically invisible. Search Find Find Quit 185 Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Carpet Openings Chapter 4 - Horizontal Cabling Systems Cutting Carpet Openings Help To access junction boxes, cut carpet openings by following the steps in the following table. TOC Step 1 Print Cutting Carpet Openings Cut the carpet on three sides of the handhole, creating a flap 5 cm (2 in.) wider than the cover plate, as shown below. Search Search Figure 4.29: Cutting carpet Find Find Quit Pile Hook Glue the nylon tape fasteners to the carpet and floor to provide a neat, safe carpet access panel. - + 186 Carpet Openings Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Cutting Carpet Openings, continued Help Step TOC 2 3 Cutting Carpet Openings Glue nylon tape fasteners to the: • Carpet flap. • Floor. Glue down the surrounding carpet edge. Print Search Search Find Carpet Openings Over Trench Duct Find To lay carpet over a trench duct, either: Quit • Put a seam down one side of the trench. The carpet can be folded back when access is required. or • Cut sections of carpet and secure them to each trench cover section using a suitable adhesive. 187 Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® General Conduit Distribution Chapter 4 - Horizontal Cabling Systems Introduction Help General Conduit Distribution A conduit system consists of conduits installed from the telecommunications closet to the work area outlets in the floor, walls, or columns of a building. See “Advantages of Conduit Systems” and “Disadvantages of Conduit Systems” in this chapter. For small buildings, an underfloor conduit system can furnish cable support and concealment: • With a sufficient number of outlets. • When offices will require a minimum of rearranging. Figure 4.30: A typical underfloor conduit system TOC Print Search Search Find Telecommunications Closet Find Quit Wall Outlets Floor Outlet - + 188 General Conduit Distribution Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Introduction, continued Help Figure 4.31: Underfloor conduit extended to individual outlets TOC Print Search Search Find Telecommunications Closet - Telecommunications Outlet Box Distribution Terminal Cabinet Conduit + Find Quit NOTE: This design can be used above a suspended ceiling as a home-run conduit system. 189 Design Considerations for Conduit Distribution Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Suitable Conduit Design Considerations for Conduit Distribution The types of conduit suitable for use in buildings are: Help TOC • Intermediate metal conduit. • Rigid metal conduit. • Rigid nonmetallic conduit. Search • Electrical metallic tubing. Search • Flexible metallic tubing. • Others permitted by the appropriate electrical codes. NOTE: Requirements for these conduit types are provided in Articles 345-350 of ANSI/NFPA 70. Requirements for liquidtight conduits are provided in Article 351 of ANSI/NFPA 70. Print Find Find Quit 190 Design Considerations for Conduit Distribution Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Unsuitable Conduit Help IMPORTANT: Flexible conduit (such as metal flex conduit) is not recommended for use in buildings, because of the disadvantages explained below. TOC During cable pulling flexible conduit tends to: Search • Creep. • Shift. • Cause sheath damage to the cable. Use flexible conduit only in situations where it is the only practical alternative. NOTE: If flexible conduit must be used, increase the conduit size by one trade size. Print Search Find Find Quit 191 Design Considerations for Conduit Distribution Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Acceptable Conduit Runs Help Design and install conduit runs to: TOC • Run in the most direct route possible (usually parallel to building lines), preferably with no more than two 90° bends between pull points or pull boxes. • Contain no 90° condulets (also known as an LB). • Contain no continuous sections longer than 30 m (98 ft.). • Be bonded to ground on one or both ends, in accordance with ANSI/TIA/ EIA-607. • Withstand the environment to which they will be exposed. NOTES: • For runs that total more than 30 m (98 ft.) in length, insert pull points or pull boxes so that no segment between points/boxes exceeds the 30 m (98-ft.) limit. Print Search Search Find Find Quit • It is recommended that total conduit runs be kept to 45 m (150 ft.) or less (including the sections through pull boxes). 192 Design Considerations for Conduit Distribution Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Unacceptable Conduit Runs Help Do not run conduit: TOC • On top of cellular floor cells. • Crosswise to cellular floor cells. • Through areas in which flammable material may be stored. • Over or adjacent to: Print Search Search – Boilers. – Incinerators. Find – Hot water lines. Find – Steam lines. In initial installations, do not use conduit in lieu of feeder ducts: • Quit Between the distribution ducts and the telecommunications closet. or • To supplement the feeder capacity of the system. NOTES: • Never place aluminum or thin-walled plastic conduit in concrete floors. • See “Avoiding Electromagnetic Interference (EMI)” in this chapter. 193 Design Considerations for Conduit Distribution Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Recommended Conduit Capacity Help To ensure proper capacity for cabling, a conduit from the telecommunications closet should not serve more than three outlet boxes. Conduit size is generally designed so that its diameter increases incrementally as the run approaches the telecommunications closet from the furthest outlet box. TOC The conduit size for horizontal cable must accommodate: Print Search • Multiple building occupants. Search • Cables placed at different times. Find NOTE: See “Conduit Capacity” in this chapter. To determine the cross-sectional area of a cable or conduit from its nominal diameter, use the following formula: Find Quit Cross Sectional Area = (0.785) x (Diameter) 2 Treat multiconductor cables (i.e., two or more conductors under a shared jacket) as a single cable for calculating percentage conduit fill area. For cables with an elliptical cross section, use the larger diameter of the ellipse as the diameter in the equation above. 194 Design Considerations for Conduit Distribution Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Bend Radii for Conduits Help The radius of a conduit bend must be at least 6 to 10 times the diameter of the conduit, depending on its size. Choose the bend radii for conduits according to the guidelines in the chart below. TOC Conduit bends should be smooth and even and should not contain kinks or other discontinuities that may have detrimental effects on pulling tension or cable integrity during or after installation. Print Search Search Table 4.15: Bend radii guidelines If The Conduit Has An Internal Diameter Of . . . The Bend Radius Must Be At Least . . . 5.1 cm (2 in.) or less 6 times the internal conduit diameter. More than 5.1 cm (2 in.) 10 times the internal conduit diameter. NOTE: For additional information on conduit bend radius requirements and recommendations, see specifications ANSI/NFPA 70 (Chapter 9) and ANSI/TIA/EIA-569-A, (Chapter 5, Table 5.2-1). In Canada, refer to CSA C22.1 (Sections 12-900 through 12-2502) and CSA T530. These specifications provide bend radius guidelines for standard trade-size conduits. Find Find Quit 195 Design Considerations for Conduit Distribution Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Designs with Conduit Bends Help The following table provides guidelines for adapting designs to conduits with bends. TOC NOTE: Consider an offset as equivalent to a 90º bend. Print Search Table 4.16: Adapting designs If A Conduit Run Requires . . . Then . . . Search More than two 90º bends Provide a pull box between sections with 2 bends or less. Find A reverse bend (between 100° and 180º) Insert a pull point or pull box at each bend having an angle from 100º to 180º. Find Quit More than two 90º bends between pull points or pull boxes For each additional bend: • Derate the design capacity by 15 percent. or • Use the next larger size of conduit. 196 Design Considerations for Conduit Distribution Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Using Three Bends in Conduit Help A third bend may be acceptable in a pull section without derating the conduit’s capacity if : TOC • The run is not longer than 10 m (33 ft.). Print or Search • The conduit size is increased to the next trade size. Search or • One of the bends is located within 30 cm (12 in.) of the cable feed end. ( This exception only applies to placing operations where cable is pushed around the first bend.) Find Find Quit 197 Design Considerations for Conduit Distribution Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Conduit Terminations Help Ream all conduit ends and fit them with an insulated bushing to eliminate sharp edges that can damage cables during installation or service. TOC Conduits that enter a telecommunications closet should terminate near the corners to allow for proper cable racking. Terminate these conduits as close as possible to the wall where the backboard is mounted (to minimize the cable route inside the closet). Terminate conduits that protrude through the structural floor 2.5-7.5 cm (1-3 in.) above the surface. This prevents cleaning solvents or other fluids from flowing into the conduit. NOTE: Maintain the integrity of all firestop barriers for all floor penetrations. See “Terminating Conduit Inside a Building” in Chapter 8 for terminations of conduits entering a building and Chapter 22, “Firestopping.” Where possible, make the telecommunications closet ceiling higher than the office ceiling. The difference in height will eliminate a bend in the conduit. (See Chapter 6, “ Telecommunications Closets and Rooms,” and ANSI/NFPA 70, Section 2, Illustration 4. In Canada, refer to CSA C22.1 and CSA T530.) Print Search Search Find Find Quit 198 Design Considerations for Conduit Distribution Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Completing Conduit Installation Help After installation, leave conduits: TOC • Clean, dry, and unobstructed. • Capped for protection. • Labeled for identification. Search • Reamed and fitted with bushings. Search Equip all conduits with a plastic or nylon line (also called a “fish tape” or “pull cord”) with a minimum test rating of 90 kg (200 lb). Print Find Find Quit 199 Pierce Wye Conduit System Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Recommended Uses Help The Pierce Wye conduit system is recommended for post-cabling various types of buildings to preselected locations. The system is particularly recommended for slab-on-grade construction (e.g., motels, townhouses, apartments, small shopping centers), in which concrete is placed directly on soil without a basement or crawl space. Slab-on-grade construction requires special consideration be given to maintaining the level of the underfloor distribution system. TOC Pierce Wye conduit systems also are often used to serve trailer parks and permanent boat docks. Find Pierce Wye Conduit System Print Search Search Find Quit 200 Pierce Wye Conduit System Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Advantages of Wye Couplings Help Use a Wye coupling in place of a pull box. The coupling: TOC • Permits one-way cabling to a common termination point. • Eliminates looping of conduit and cabling. • Reduces the need to encroach on customer premises for maintenance calls. Search • Saves substantial amounts of: Search – Home-run conduit. – Cabling. – Labor. Print Find Find Quit 201 Pierce Wye Conduit System Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Installing Wye Couplings Help A Wye coupling can be installed using trade size 1 and trade size ¾ conduit made of: TOC • PVC. Print • Metal. Search If PVC conduit is used: • Securely cement sections together. • Do not allow it to pass through fire-rated separations. Search Find When installing a Wye coupling, ensure that: Find • All joints are properly joined together. Quit • The conduit is sized to comply with normal conduit design fill for the type of cable installed. • The bends (90° and 45° with a 6-in. radius) and outlet boxes are placed as indicated in the following illustrations. 202 Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Pierce Wye Conduit System Chapter 4 - Horizontal Cabling Systems Installing Wye Couplings, continued Figure 4.32: Placing bends and outlet boxes Help TOC Typical Design for an Eight Unit Building Typical Fitting Arrangement at Each End Unit and the Terminal Unit 1 Print Unit 8 Intermediate Units MC 1048 Cable Enclosure 1.5 in. ABS Pipe Pre-Wire Bracket 1.5 in. ABS Pipe NOTE: Multiply inches by 2.54 to convert to centimeters. Search Outer Wall 1.5 in. ABS 90 Bend Search 8 ft. (10 in.) Floor - Find 1.5 in. Coupling J or T 1.5 in. 90 Bend + 1.5 in. Sanitary Tee Standard 1.5 in. ABS or PVC Conduit - + Find Quit Typical Fitting Arrangement at Each End Unit and the Terminal - 1.5 in. ABS Pipe + Nylon Core at Last Unit 1.5 in. Sanitary Tee J or T J or T Retrieving the Core 1.5 in. ABS Pipe Tied Down Terminal End - + 203 Pull Boxes for Conduits Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Installing Boxes Help Pull Boxes for Conduits Install: TOC • Pull boxes in easily accessible locations. • Horizontal cabling boxes immediately above suspended ceilings. NOTE: The following pull box information applies to inside plant cables only. For direct access to a box, provide a suitable, marked, hinged panel (or equivalent) in the suspended ceiling. This access panel can also serve as the cover for the box. Print Search Search Find Find Quit 204 Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Pull Boxes for Conduits Chapter 4 - Horizontal Cabling Systems Installing Boxes, continued Help The following illustration shows recommended box configurations. TOC Figure 4.33: Recommended box configurations - + Print Search Use This Not This Search Find Find Quit Use This Not This - + 205 Pull Boxes for Conduits Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Slip-sleeves and Gutters Help The following chart describes slip-sleeves and gutters. TOC Table 4.17: Slip-sleeves and gutters A... Is . . . Slip-sleeve A conduit sleeve which is: Gutter Print Search • Larger than the main conduit. • Slipped over an opening in a conduit run after the cable is in place. Search A square, sheet-metal housing which is placed over an opening in a conduit run. Find Find Quit 206 Pull Boxes for Conduits Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Using Slip-sleeves or Gutters Help Slip-sleeves or gutters: TOC • Can be used in place of a pull box. • Will provide more space for pulling. • Are more economical to install than a pull box. Search Do not use slip-sleeves or gutters as splice locations. Search To allow for the installation of slip-sleeves and gutters, provide an opening in the main conduit which is long enough to form a cable loop during the pulling-in operation. Print Find Find Quit 207 Pull Boxes for Conduits Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Sizes and Purposes of Boxes, Slip-sleeves, and Gutters Help For horizontal cable, the box, slip-sleeve, or gutter’s: TOC • Width and depth must be adequate for fishing, pulling, and looping the cable. • Length must be 12 times the diameter of the largest conduit. In some cases (e.g., when large cables are planned to serve multiple work areas), a box length of 16 times the diameter of the largest conduit may be appropriate. These requirements facilitate: • Pulling cable into the box. • Looping cable for pulling into the next length of conduit. Print Search Search Find Find Quit 208 Pull Boxes for Conduits Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Boxes for Pulling and Looping Cable Help Boxes for pulling and looping cable are suitable only for cables that have an outside diameter of 5 cm (2 in.) or less. If the cable is larger than 5 cm (2 in.) in diameter, do not locate the box in the ceiling; route the cable and conduit down a wall or column. TOC Pull boxes must be placed in readily accessible locations. Place a pull box in interstitial ceiling space only if the pull box is: • Listed for that purpose. Print Search Search Find and • Placed above a suitably marked, removable ceiling panel. Do not use pull boxes for splicing cable. Find Quit NOTE: Splices are not permitted in twisted-pair horizontal cables. 209 Pull Boxes for Conduits Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Placing Pull Boxes in Conduit Sections Help Place pull boxes in sections of conduit that: TOC • Are 30 m (98 ft.) or more in length. Print or • • Contain more than two 90 o bends. Search or Search Contain a reverse bend. Do not use a pull box in lieu of a bend. Align conduits that enter the pull box from opposite ends with each other. Find Find Quit 210 Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Pull Boxes for Conduits Choosing a Pull Box Size Use the following table to select the proper size of pull box. Table 4.18: Minimum space requirements in pull boxes having one conduit each in opposite ends of the box Maximum Trade Size of Conduit Chapter 4 - Horizontal Cabling Systems Size of Box For Each Additional Conduit Increase Width Help Width Length Depth 3/4 102 mm (4 in.) 305 mm (12 in.) 76 mm (3 in.) 51 mm (2 in.) 1 102 mm (4 in.) 406 mm (16 in.) 76 mm (3 in.) 51 mm (2 in.) 1 1/4 152 mm (6 in.) 508 mm (20 in.) 76 mm (3 in.) 76 mm (3 in.) 1 1/2 203 mm (8 in.) 686 mm (27 in.) 102 mm (4 in.) 102 mm (4 in.) Search 2 203 mm (8 in.) 914 mm (36 in.) 102 mm (4 in.) 127 mm (5 in.) Find 2 1/2 254 mm (10 in.) 1067 mm (42 in.) 127 mm (5 in.) 152 mm (6 in.) Find 3 305 mm (12 in.) 1219 mm (48 in.) 127 mm (5 in.) 152 mm (6 in.) 3 1/2 305 mm (12 in.) 1372 mm (54 in.) 152 mm (6 in.) 152 mm (6 in.) 4 381 mm (15 in.) 1524 mm (60 in.) 203 mm (8 in.) 203 mm (8 in.) W Print Search Quit - L TOC + D 211 Access Floors Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Introduction Access Floors Help An access floor is a floor that: TOC • Is raised above an existing subfloor. • Provides accessible space under the floor panels. Print Access floors: Search • Are also called “raised” floors. Search • Are most often used in computer rooms and equipment rooms. • Are available with combustible, noncombustible, and composite panels and can be designed for seismic and other special conditions. • Make use of a plenum area below the finished floor that may also be suitable for air handling purposes. Find Find Quit See “Access Floor Advantages” and “Access Floor Disadvantages” in this chapter. 212 Access Floors Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Floor Components Help An access floor typically consists of : TOC • Steel footings that rest on the subfloor. These footings provide distributed support for floor loads. • Pedestals that support and interlock with lateral bracing (stringers) and/or panels. These pedestals are evenly spaced on the steel footings and are adjustable to compensate for unevenness of the subfloor. • • Floors that may or may not be constructed with stringers. When used, they are assembled to form a framework of panel receptacles. These stringers provide lateral support by interlocking with the pedestals. Modular floor panels that rest on the stringers and/or pedestals. Panel sizes typically range from 46 cm - 61 cm (18 in.-24 in.) square. Plain or carpeted panel surfaces may be selected to accommodate the functional and aesthetic needs of the area they occupy. Print Search Search Find Find Quit 213 Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Access Floors Chapter 4 - Horizontal Cabling Systems Floor Components, continued Help The basic components of a stringered access floor system are shown in the following illustration. TOC Print Figure 4.34: Stringered access floor system Search 46.36 cm (18.25 in.) 46.36 cm (18.25 in.) Search Find Carpets or Tiles Find Quit Stringers Steel Footings Aluminum Locking Pedestals - + 214 Access Floors Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Stringered Systems Help Stringered systems have lateral bracing (stringers) between pedestal supports. When stringered systems are used, they shall be bolted or snapped to the pedestal heads. Stringered systems: TOC • Brace the pedestals for improved lateral stability. • Provide additional support for the panels. • Facilitate frequent removal and replacement of floor panels. NOTE: To facilitate cable tray placement, it is recommended that they be installed before the floor stringers are attached to the pedestals. Print Search Search Find Find Quit 215 Access Floors Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Freestanding and Cornerlock Systems Help Freestanding and cornerlock access floors consist of panels that are supported solely by pedestals. Freestanding systems rest on pedestal supports with no mechanical fastening whereas cornerlock systems mechanically fasten floor panels to the pedestal heads at each corner. Of the two, cornerlock systems add increased stability and are preferred for general office use. Restrict use of freestanding systems to installations with finished heights of 30 cm (12 in.) or less. TOC Print Search Search Find Find Quit 216 Design Considerations for Access Floors Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Minimum Finished Floor Height Design Considerations for Access Floors Help The minimum finished height of access flooring depends on its use and location. When access flooring is used in: TOC • Print General office areas, design the finished floor to be 20-cm (8-in.) high or higher. NOTE: Although ANSI/TIA/EIA-569-A specifies 15 cm (6 in.) as the minimum finished height for access floors, at least 20 cm (8 in.) is necessar y to provide sufficient space for cable trays and other means of cable management. • A computer or control room environment where the plenum is used for HVAC, the finished floor height must be 30 cm (12 in.) or greater. • Regardless of the height of the finished floor, there should be a minimum of 5 cm (2 in.) of free space between the top of the cable tray side rails and the underside of the stringers. • If cable trays with covers or raceways are used, the free space above the tray should allow for easy removal of covers. Search Search Find Find Quit 217 Design Considerations for Access Floors Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Building Structure Help When planning access flooring for new or existing buildings, consider the types of building structure available. Two common types include: TOC • Print • Depressed Slab—the area to receive the access flooring is depressed (used only in new construction). The depth of depression must equal the height of the finished access floor to avoid the need for ramps or steps. For information on assuring accessibility of public spaces by disabled individuals, see Chapter 18, “Miscellaneous and Special Situations.” Normal Slab—Where the slab is not depressed (such as in existing and renovated buildings), make provisions for a structural transition to the access floor. Follow building codes for ramp and step assemblies. Search Search Find Find Quit 218 Design Considerations for Access Floors Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Building Layout Help Design the layout of the access floor before installing any equipment or telecommunications cabling. TOC Whenever possible, design the floor plan so that the telecommunications closet is adjacent to the access floor area that it will serve. Use threaded sleeves or conduit to connect the telecommunications closet to the access floor area. In cases where the telecommunications closet and the access floor area it serves are not adjacent, other methods of connecting them will be required. In these cases, ensure that the interconnecting pathways are adequate to serve the access floor area. Print Search Search Find Find Quit 219 Design Considerations for Access Floors Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Floor Penetrations Help Design penetrations through the access floor for the type and number of access points required to support the work area outlets. Do not place cable egress or outlets in traffic areas or other locations where they may create a safety hazard. Consult the manufacturer’s guidelines to ensure compatibility between access floor components and service fittings. TOC Maintain the integrity of all firestop assemblies which must be penetrated by cable or pathways. Search Print Search Find Bonding and Grounding All metal parts of an access floor should be bonded to ground. For bonding and grounding, follow access floor manufacturer’s guidelines and all applicable building and electrical codes. Find Quit 220 Design Considerations for Access Floors Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Floor Panel Materials Help Where cabling is not contained in conduit, panels must be made completely of noncombustible materials. The flame-spread rating of the floor panels, exclusive of covering, must be Class A or better when tested in accordance with ASTM 84-80 (Ref. 4.17 in “Referenced Standards”) and NFPA 255 (Ref. 4.18 in “Referenced Standards”). Panels must be made so that their flame-spread integrity is not affected when the panel is cut. In Canada, refer to the National Building Code of Canada. TOC For general offices, composite steel and concrete panels are popular because they: Find • Are noncombustible. • Can bear dynamic loads. • Come close to sounding and feeling like an actual concrete-slab floor. Print Search Search Find Quit 221 Design Considerations for Access Floors Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Floor Panel Coverings Help Floor panels are covered according to their intended use, as shown in the following table. TOC Print Table 4.19: Coverings Panels To Be Used In A(n) . . . Will Be Covered In . . . Search Computer room • Search • Office • High-pressure laminate. or Vinyl or other durable tile. Factory-laminated carpet. or • Nothing (i.e., ready to receive carpet tiles). Find Find Quit 222 Design Considerations for Access Floors Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Load-bearing Capacity Help All access floor panels and understructure must be tested and meet the requirements of the Ceilings and Interior Systems Construction Association (CISCA) test methods (Ref. 4.19 in “Referenced Standards”). TOC Access floors may be designed to bear different uniform loads and concentrated loads, according to the intended use of the room. The following table shows the load-bearing capacity of access floors designed for equipment rooms and office space. Search Search Find Table 4.20: Load capacity Application Print Uniform Load Capacity Concentrated Load Capacity Find Quit Equipment room (medium duty) 4.8 kPa (100 lbf/ft 2 ) General office (medium duty) 2.4 kPa (50 lbf/ft 2 ) 8.8 kN (2,000 lb) 223 Design Considerations for Access Floors Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Load-bearing Capacity, continued Help Dynamic loads are also an important measure of access floor performance for both distribution facilities and office applications. Dynamic loads are created by: TOC • Accidental impacts (e.g., falling objects). • Rolling objects (e.g., paper carts, mail mobiles, other wheeled vehicles). When designing an access floor, check with floor manufacturers to determine the rolling load and impact load ratings for their floor systems. Print Search Search Find Find Quit 224 Design Considerations for Access Floors Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Running Telecommunications Cables Help Telecommunications cables in an access floor plenum should be placed in pathways in a manner that provides sufficient space for service personnel to stand on the structural floor without risk of damaging the cable. Use grommets that are flush-mounted in a floor panel or access door to protect work area cables that connect to concealed outlets. TOC For good cable management, consider the following methods of containment for main runs: Search • Dedicated routes. Find • Enclosed raceway distribution. Find • Zone distribution. • Cable trays. Print Search Quit NOTE: Plenum-rated cable may be required. Refer to ANSI/NFPA 70, Section 300-22 and CSA C22.1, Section 12-010. 225 Design Considerations for Access Floors Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Electrical Power Circuits Help Electrical power circuits that occupy access floor space must be placed in rigid or flexible conduit (or a combination of rigid and flexible sections). For required clearances for electromagnetic isolation and safety, see “Avoiding Electromagnetic Interference (EMI)” in this chapter, Chapter 21 “Electromagnetic Compatibility,” and Article 800 of ANSI/NFPA 70. In Canada, see CSA T529 and CSA C22.1. TOC Print Search Search Terminating Electrical Power Circuits Find Terminate electrical power circuits in a receptacle mounted on the underside of a floor panel. Provide access to the receptacle through a grommet in the panel. Find Quit To provide circuit flexibility: • Terminate the conduit and cabling to an intermediate junction box equipped with multiple plug connections. • Connect the receptacles to the junction box, using flexible leads. 226 Design Considerations for Access Floors Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Effects of Air Plenum Use on Cabling Help The space under an access floor often may be used as a plenum for distributing conditioned air throughout the room (or, in some cases, the entire office area). When the plenum is used for air distribution, check local codes for applicable requirements for power and telecommunications cabling. TOC NOTE: Plenum-rated cable may be required. Refer to ANSI/NFPA 70, Section 300-22 and CSA C22.1, Section 12-010. If the space under an access floor is not used as an air-handling plenum, most codes allow certain types of telecommunications cables to be run without special enclosure requirements. ( This is also true for an above-ceiling plenum which is not used for air handling). In office areas, code requirements may be different for rooms such as telecommunications closets, where special fire suppression systems may be installed. Print Search Search Find Find Quit 227 Ceiling Distribution Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Introduction Help Ceiling distribution systems use the interstitial space between: TOC Ceiling Distribution Systems • The structural ceiling (physically part of the roof or floor above). Print and • An accessible ceiling grid suspended below the structural ceiling. Several methods of using ceiling distribution to service work area locations are explained in the following sections. Search Search Find Find Quit 228 Ceiling Distribution Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Acceptable Methods of Distribution Help The methods of ceiling cable distribution described in this section are generally acceptable if the: TOC • Ceiling is adequate and suitable. Print • Ceiling space is available for cabling pathways. Search • Ceiling space is used only for horizontal cables serving the floor below. • Ceiling access is controlled by the building owner. • Code requirements for design, installation, and pathways are met. • Building owner is aware of his or her responsibility for any damage, injury, or inconvenience to occupants that may result from technicians working in the ceiling. • Areas used for cabling pathways are fully accessible from the floor below (i.e., not obstructed by fixed ceiling tiles, dry wall, or plaster). • Ceiling tiles are removable and placed at a height of no greater than 3.4 m (11 ft.) above the finished floor. Search Find Find Quit 229 Ceiling Distribution Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Ceiling Zones Method Help In the “ceiling zones” method of ceiling distribution, divide the usable floor area into zones of 35 m 2 to 82 m 2 (365 ft 2 to 900 ft 2 ) each. When convenient, it is preferable that zones be divided by building columns. Pathways to each zone may be provided using cable trays within the ceiling area or enclosed conduits or raceways. The raceways, conduits or cable trays should extend from the telecommunications closet to the mid-point of the zone. From that point, the pathway should extend to the top of the utility columns or wall conduit. TOC NOTE: Plenum-rated cable tray may be required. Refer to ANSI/NFPA 70, Section 300-22 and CSA C22.1, Section 12.010. See ANSI/NFPA 70, Section 318.4 for restrictions on the use of cable trays. Print Search Search Find Find Quit 230 Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Ceiling Distribution Systems Chapter 4 - Horizontal Cabling Systems Typical Ceiling Zone Distribution Using Conduit Help The following illustration shows a typical ceiling distribution system using home-run conduit to telecommunications zones. TOC Print Figure 4.35: Using home-run conduit Search Telepole Trade Size 3/4 Conduit Search Junction Box Trade Size 2 Conduit Telecommunications Closet Find Core Trade Size 3 Conduit Find Telecommunications Closet Quit 9 m (30 ft.) 6 m (20 ft) - + NOTE: Only one home run is completed. 231 Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Ceiling Distribution Systems Chapter 4 - Horizontal Cabling Systems Illustration of Ceiling Zones Help The illustrations that follow show a: TOC • Typical zoned ceiling distribution system (plan view). Print Figure 4.36: Typical zoned ceiling NOTE: This figure represents only a schematic depiction of a ceiling distribution system. Actual pathways to ceiling zones should be organized in a neat and orderly fashion to facilitate ongoing ser vice and maintenance of the ceiling pathways. - Telecommunications Zone Typical Wiring Layout 6m (20 ft) Coiled Slack in Cable To be Cabled Directly Search Search 6m (20 ft) Find TC Find Closet Linkage Pathway Quit Core Area To be Cabled Directly TC + 232 Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Ceiling Distribution Systems Chapter 4 - Horizontal Cabling Systems Illustration of Ceiling Zones, continued Help • TOC Typical conduit-based ceiling zone distribution system (elevation view). Print Figure 4.37: Conduitbased ceiling zone Search To Telecommunications Closet Conduit Search 9 m (20 ft.) Maximum Ceiling Tile Designated as Access Tile to "Zoned Conduit" Service Pole Find Find Trade Size 1 Conduit Quit - + 4 in. x 4 in. Deep Type Telecommunications Outlet Box C/W Single Gang Plaster Ring Trade Size 1 Conduit Trade Size 1 Conduit 4 in. x 4 in. Deep Type Telecommunications Outlet Box. Equipped with C/W Single Gang Plaster Ring. Telephone Zone of 45m2 (500 ft.) 233 Telecommunications Distribution Methods Manual General Design Guidelines on CD-ROM, 8th edition, © 1998 BICSI for Ceiling Systems Chapter 4 - Horizontal Cabling Systems General Design Guidelines for Ceiling Systems Introduction Help ® Carefully plan the area above a suspended ceiling to allow room for the different utilities and telecommunications services it contains. Coordination between the various trades that use the ceiling space is essential. TOC See “Avoiding Electromagnetic Interference (EMI)” in this chapter. Search Print Search Find Find Quit 234 General Design Guidelines for Ceiling Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Determining Adequate Ceiling Space Help To determine how much ceiling space is adequate: TOC • • Consider the size and depth of the: Print – Structural beams. – Column caps. Search – Mechanical services. Search Allow for a minimum of: – 8 cm (3 in.) of clear vertical space above conduits and cables. – 30 cm (12 in.) of clear vertical space above the tray or raceway for overhead ceiling cable tray or raceway systems. (See ANSI/TIA/EIA-569-A and CSA 22.1, Section 12-2202 [7].) Find Find Quit When designing the layout of horizontal pathways in ceiling spaces, ensure that other building components (e.g., lighting fixtures, structural supports, air ducts) do not restrict access to cable trays or raceways. 235 General Design Guidelines for Ceiling Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Choosing the Ceiling Panels Help Choose which type of ceiling panel to install according to the following table. TOC Table 4.21: Guidelines for choosing ceiling panels Use A Ceiling Panel That Is . . . For A . . . Readily removable Lay-in type panel on either: • Single support channel. or • Double support channel. Search NOTE: Not readily removable Print Securely install and brace support channels to prevent both vertical and horizontal movement. Search Find Find Quit Lock-in type panel that requires a conduit system. 236 General Design Guidelines for Ceiling Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Restrictions on Ceiling Cabling Help Cabling within ceilings used as a plenum for environmental air must conform to the requirements of: TOC • ANSI/NFPA 70, Section 300-22 and CSA C22.1, Section 12-010. Print • Local codes. Search Ceiling Zone Conduit Restrictions Search A zone conduit system may be allowed in an air plenum ceiling if: Find • Find Conduits terminate in junction boxes. and • Quit Short runs of smaller conduit are extended from the junction boxes to the work area outlets. IMPORTANT: Verify the use of ceiling zones in air plenums with code authorities. Local codes may deviate from ANSI/NFPA 70 (in Canada, the National Building Code of Canada and CSA C22.1). 237 General Design Guidelines for Ceiling Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Pathway and Cable Support Help Every ceiling distribution system must provide proper support for cables from the telecommunications closet to the work areas it serves. Ceiling panels, support channels ( T-bars), and vertical supports are not proper supports. Ceiling conduits, raceways, cable trays, and cabling must be suspended from or attached to the structural ceiling or walls with hardware or other installation aids specifically designed to support their weight. TOC The pathways must: Search • Have adequate support to withstand pulling the cables. • Be installed with at least 8 cm (3 in.) of clear vertical space above the ceiling tiles and support channels ( T-bars) to ensure accessibility. Do not allow horizontal pathways or cables to rest directly on or be supported by ceiling panels, support channels ( T-bars), vertical supports, or other components of the suspended ceiling. It is important to provide sufficient space between the suspended ceiling structure and the telecommunications pathways/cables to install, maneuver, and store ceiling tiles during service. When sufficient space is available above the pathway, provide up to 15 cm (6 in.) between the suspended ceiling and the cabling pathways. For additional clearance requirements, see “Avoiding Electromagnetic Interference (EMI)” in this chapter. Print Search Find Find Quit 238 General Design Guidelines for Ceiling Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Pathway and Cable Support, continued Help Where building codes permit telecommunications cables to be placed in suspended ceiling spaces without conduit, ceiling zone distribution pathways may consist of: TOC • Cable trays. Print Search and/or • Open-top cable supports (J-supports). NOTE: When using J-supports, locate them on 122-cm (48-in.)-153-cm (60-in.) centers to adequately support and distribute the cable’s weight. These types of supports may typically hold up to fifty 6.1-cm (0.25-in.) diameter cables. Search Find Find Quit Suspended cables must be installed with at least 8 cm (3 in.) of clear vertical space above the ceiling tiles and support channels ( T-bars). For large quantities of cables (50-75) that converge at the telecommunications closet and other areas, provide cable trays or other special supports that are specifically designed to support the required cable weight and volume. Applicable specifications include ANSI/NFPA 70, Article 318 (in Canada, CSA C22.1, Sections 2-126 through 2-128). 239 General Design Guidelines for Ceiling Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Termination Space Help Allow maximum wall space in the telecommunications closet for the horizontal cable terminations. Spare cables may be left in the ceiling for future use. This practice reduces: TOC • Inconvenience to office personnel. • The time and expense associated with work area equipment moves, adds, and changes. For details on wall and rack space for cross-connects, see Chapter 6, “ Telecommunications Closets and Rooms.” Print Search Search Find Find Quit 240 Cable Tray Design for Ceiling Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Cable Tray Systems Help Cable tray systems are commonly used as distribution systems for cabling within a building. They are often preferable to rigid conduit and raceway systems because of their greater accessibility and ability to accommodate change (see “Ceiling System Advantages” and “Ceiling System Disadvantages” in this chapter). Cable tray systems: TOC • Are rigid, prefabricated support structures that support telecommunications cables and cabling. Search • Must be installed to meet: Find Cable Tray Design for Ceiling Systems Print Search – ANSI/NFPA 70, Article 318-Cable Trays. Find – National and local building codes. (In Canada, see CSA C22.1-Cable Trays, Section 12-2200 and CSA T530.) Quit NOTE: ANSI/NFPA 70 is sometimes referred to as the “National Electrical Code” or “NEC .” CSA C22.1 is sometimes referred to as the “Canadian Electrical Code.” 241 Cable Tray Design for Ceiling Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Cable Tray Systems, continued Help Although it may be allowed by some building codes, telecommunications distribution designers are strongly advised not to use shared cable trays to distribute telecommunications and power cables. If trays or wireways are shared, the power and telecommunications cables must be separated by a grounded metallic barrier. TOC When a tray is used in the ceiling area, provide conduit from the tray to the outlets or zones, except in cases where loose cables are permitted by and meet the applicable codes. Search NOTE: The inside of a cable tray must be free of burrs, sharp edges, or projections which can damage cable insulation. Find Print Search Find Quit 242 Cable Tray Design for Ceiling Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Cable Tray Fittings Help The fittings used to change the direction or size of a cable tray include: TOC • Elbows. • Reducers. • Cross-overs. Search • Tees. Search Print Cable Tray Accessories Find The accessories used with cable trays include: Find • Covers. Quit • Hold-down devices. • Dropouts. • Conduit adapters. • Dividers. 243 Cable Tray Design for Ceiling Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Types of Cable Trays Help The basic types of cable trays are described in the following table. TOC Table 4.22: Cable trays Print Type Of Cable Tray Structural Description Ladder Two side rails connected by individual transverse members. Ventilated trough A ventilated bottom with side rails. Ventilated channel Channel section with a one-piece bottom no more than 15 cm (6 in.) wide. Solid bottom Solid bottom with longitudinal side rails. Spine Open tray having a central rigid spine with cable support ribs along the length at 90° angles. Search Search Find Find Quit 244 Cable Tray Design for Ceiling Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Cable Tray Dimensions Help Dimensions for four common types of cable trays are shown in the chart below. TOC NOTES: • Consult cable tray manufacturers for tolerances of specific models. • The dimensions below illustrate a standard variety of trays sizes to suit most applications for horizontal cable distribution. Other sizes and designs are available to accommodate special needs and installations. Consult cable tray manufacturers for a comprehensive listing of standard models. Print Search Search Find Find Quit 245 Cable Tray Design for Ceiling Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Cable Tray Dimensions, continued Help Table 4.23: Cable trays (common types) TOC Lengths Ladder Ventilated Trough Ventilated Channel Solid-bottom 3.7 m (12 ft.) 7.3 m (24 ft.) 3.7 m (12 ft.) 7.3 m (24 ft.) 3.7 m (12 ft.) 7.3 m (24 ft.) 3.7 m (12 ft.) 7.3 m (24 ft.) Print Search Search Widths (Inside) 15 30 46 61 76 91 cm cm cm cm cm cm (6 in.) (12 in.) (18 in.) (24 in.) (30 in.) (36 in.) 15 30 46 61 76 91 cm cm cm cm cm cm (6 in.) (12 in.) (18 in.) (24 in.) (30 in.) (36 in.) 7.6 cm (3 in.) 10 cm (4 in.) 15 cm (6 in.) — — — 15 cm (6 in.) 30 cm (12 in.) 46 cm (18 in.) 61 cm (24 in.) 76 cm (30 in.) 91 cm (36 in.) Find Find Quit NOTE: The side rail outside depths (height) can be as much as 32 mm (1¼ in.) more than the inside loading depth for ladder, ventilated trough and solid bottom cable tray. 246 Cable Tray Design for Ceiling Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Cable Tray Dimensions, continued Help Table 4.23: Cable trays (common types), continued TOC Depths Ladder Ventilated Trough Ventilated Channel Solid-bottom 7.6 cm (3 in.) 10 cm (4 in.) 13 cm (5 in.) 15 cm (6 in.) 7.6 cm (3 in.) 10 cm (4 in.) 13 cm (5 in.) 15 cm (6 in.) 3.2 cm (1¼ in.) 4.4 cm (1¾ in.) — — 7.6 cm (3 in.) 10 cm (4 in.) 13 cm (5 in.) 15 cm (6 in.) Print Search Search Find Rung spacing Radii 15 23 30 46 cm (6 in.) — cm (9 in.) cm (12 in.) cm (18 in.) — — Find Quit 30 cm (12 in.) 30 cm (12 in.) 30 cm (12 in.) 30 cm (12 in.) 61 cm (24 in.) 61 cm (24 in.) 61 cm (24 in.) 61 cm (24 in.) 91 cm (36 in.) 91 cm (36 in.) 91 cm (36 in.) 91 cm (36 in.) 247 Cable Tray Design for Ceiling Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Cable Tray Dimensions, continued Help Table 4.23: Cable trays (common types), continued TOC Degrees of arc Ladder Ventilated Trough Ventilated Channel Solid-bottom 30° 45° 60° 90° 30° 45° 60° 90° 30° 45° 60° 90° 30° 45° 60° 90° Transverse — element spacing 10 cm (4 in.) — Print Search Search Find — Find Quit 248 Cable Tray Design for Ceiling Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Capacity of Cable Trays Help The working load capacity of a cable tray system is 40% to 50% as determined by both the: TOC • Static load capacity of the tray. Print and Search • The length of the support span. The cable tray fill is limited by ANSI/NFPA 70, Section 318-9 (b) [Ladder and Ventilated Trough Cable Trays], Section 318-9 (d) [Solid Bottom Cable Trays] and Section 318-9 (e) (2) [ Ventilated Channel Cable Trays]. Search Find Find NOTE: Total cable weight per foot is rarely the limiting factor in determining the allowable cable tray fill for telcommunications cables. For horizontal cables, the allowable fill volume will usually be obtained before the allowable weight per foot is reached. Quit 249 Cable Tray Design for Ceiling Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Supporting Cable Trays Help Support cable trays by installing: TOC • Cantilever brackets. • Trapeze supports. • Individual rod suspension brackets. Support centers must be spaced according to the cable load and span, as specified for the cable tray’s type and class by the manufacturer and applicable electrical codes. Place supports so that connections between sections of the cable tray are between the support point and the quarter section of the span. Trays and wireways are usually supported on 1.5-m (5-ft.) centers, unless they are designed for greater spans. A support must also be placed within 0.6 m (2 ft.) on each side of any connection to a fitting. WARNING: Print Search Search Find Find Quit Never use cable trays as walkways, ladders, or support for personnel. Cable trays must only be used as mechanical support for cables. 250 Cable Tray Design for Ceiling Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Marking and Grounding Cable Trays Help All metallic cable trays must be grounded, but may also be used as a ground conductor. Clearly mark any cable tray that is used as an equipment grounding conductor, as specified in ANSI/NFPA 70, Section 318-3 (c) (in Canada, CSA C22.1, Sections 10 and 12). TOC Print Search Search Find Find Quit 251 Conduit and Raceway Design for Ceiling Systems Ceiling Zone Method UsingDesign Conduitfor Conduit and Raceway Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Ceiling Systems In a “home-run” ceiling conduit system, place a continuous run of conduit from the work area outlet boxes to the telecommunications closet. See “Advantages of Conduit Systems” and “Disadvantages of Conduit Systems” in this chapter. Each home-run conduit can serve from one to three outlet boxes, depending on the design and conduit size. For conduits that serve: Help TOC Print Search Search • One box, an inside diameter of 2.1 cm (¾ in.) or greater is recommended. • Two boxes, an inside diameter of 2.7 cm (1 in.) or greater is recommended. • Three boxes, an inside diameter of 3.5 cm (1¼ in.) or greater is recommended. Find For more information on conduit capacity, see “Conduit Capacity” in this chapter. Quit NOTES: Find • Always observe the air plenum requirements in specification ANSI/ANSI/NFPA 70 (in Canada, CSA C22.1, Sections 2-126 through 2-128, and the National Building Code of Canada) when using this method of distribution. • For additional information on conduit distribution, see “General Conduit Distribution” in this chapter. 252 Conduit and Raceway Design for Ceiling Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Zone Conduit Size Help The following guidelines on zone conduit size are based on the conduit capacity table in “Conduit Capacity” and on the assumptions of three cables per individual work area and one individual work area per 10 m 2 (100 ft 2 ). TOC When running up to two four-pair 100-ohm UTP cables and two optical fibers to each work area, use at least one trade size 2 conduit for each zone ranging from 35 m 2 to 60 m 2 (350 ft 2 to 600 ft 2 ). For larger zones ranging from 60 m 2 to 90 m 2 (600 ft 2 to 900 ft 2 ), use trade size 2½ conduit. Search NOTE: For conduits that contain more than one cable type, determine size on the basis of the largest diameter cable to be used and the total number of cables it is expected to hold. Print Search Find Find Quit 253 Conduit and Raceway Design for Ceiling Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Overhead Ceiling Raceway Method Help In an “overhead ceiling raceway” system, run enclosed metal raceways within the ceiling space to distribute cables. Install: TOC • Larger raceways to bring feeders into an area. Print • Smaller, lateral (distribution) raceways to branch off from the feeder and provide services to the usable floor space. Search Feed work area locations with a combination of flexible conduit or exposed cable (if codes allow). Extend the conduit or exposed cables from distribution raceways to: Search • Utility columns. • Partitioned walls. • Other service outlet locations. Find Find Quit NOTE: See the illustrations in “Typical Overhead Ceiling Raceway System” and “Overhead Ceiling Raceways and Fittings” in this chapter. When enclosed raceways and flexible conduit are used in air plenums, special plenum-rated cable should not be necessary. NOTE: In an environmental-air plenum, ANSI/NFPA 70 allows a maximum of 1.2 m (4 ft.) of flexible conduit in a continuous run (Article 300-22). In Canada, refer to the National Building Code of Canada. 254 Conduit and Raceway Design for Ceiling Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Typical Overhead Ceiling Raceway System Help The following illustration shows a typical overhead ceiling raceway system. TOC Figure 4.38: Overhead ceiling raceway system Print Search C Hanger Header Raceway Type C (Communications) Power Tap-Off Fitting Search Find Find Utility Column - Take-Off Fitting Quit Lateral Feeder Raceways + Suspended Ceiling Header Raceway Type B (Power) C Hanger Raceway Size For guidelines on raceway capacity and fill requirements, see “Determining Raceway Size” in this chapter. 255 Conduit and Raceway Design for Ceiling Systems Overhead Ceiling Raceways and Fittings The illustrations below show raceways and fittings for a typical overhead ceiling raceway system. Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Help C Hanger C Hanger Feeder raceway Type B. locked in "C" hanger by hold-down clamp. Feeder Raceway Type B Header Raceway Type C Header raceway, Type C, in "C" hanger suspended by 3/8 in. diameter threaded rod. Header Raceway Power Tap-Off Fitting Power tap-off fitting with 1/4 in. and 1/2 in. knockout mounts anywhere on raceway. Feeder Raceway - Lateral Raceway Figure 4.39: Raceways and fittings Communication Box Detail Distribution Duct Fitting Cover in Place Cover Latch Duct in Locked Cover Position Print Take-off fitting for "T" connection of lateral raceway at any point on header. Take-Off Fitting 3/8 in. Threaded Rod Secured to Building Structure TOC + Search Search C Hanger Find 1 in. Flex Conduit Telecommunications Cables - Knockouts for Flex Conduits + Find Quit Divided Raceway Duplex Telephone Outlet Cover End-Connection to Feed Power Section Entrance End Fitting Wall Box Connector Divider Raceway Cover - + Back-Connection to Feed Telecommunications blocks are easily moved or added anywhere along run. Outlet and raceway covers snap into raceway base. Telecommunications and power section may be back-fed or end-fed. Cross-Section of Divided Raceway Telecommunications Section 256 Conduit and Raceway Design for Ceiling Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Designing a Ceiling Raceway System Help Follow the steps in the procedure below to design a ceiling raceway system. TOC Step Print 1 Designing A Ceiling Raceway System Select the location of the ceiling raceways. The general rule is to place raceways parallel to either the: Search • Wall of the telecommunications closet. Search or • Longest outside building wall. NOTE: The ceiling raceway system must be designed so that cable runs extending from the horizontal crossconnect in the telecommunications closet to the telecommunications outlet in the work area are not more than 90 m (295 ft.) long. 2 Find Find Quit Determine the spacing for the raceways. They are usually spaced on 5 m-6 m (16-ft.-20-ft.) centers, starting at a point 1.2 m-3 m (4 ft.-10 ft.) from the outside wall. NOTE: Install raceways on module lines, if possible. 257 Conduit and Raceway Design for Ceiling Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Designing a Ceiling Raceway System, continued Help Step Designing A Ceiling Raceway System TOC Use the following equation to calculate the floor area that can be served by each run of a ceiling raceway: Print 3 Width of area served by an individual raceway X Length of area served by an individual raceway = Floor area served by that raceway Search Search Find 4 Use the following equation to determine the ultimate number of work areas served by each raceway run: Floor area served by one raceway run Space allocation per individual work area = Ultimate number of individual work areas served by that run Find Quit NOTE: The standard space allocation used in an office environment is one individual work area per 10 m 2 (100 ft. 2 ) of usable floor space. 258 Conduit and Raceway Design for Ceiling Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Designing a Ceiling Raceway System, continued Help Step TOC 5 Designing A Ceiling Raceway System Multiply the cross-sectional area of the raceway (cm 2 [in 2 ]) by 1.54 m 2 /cm 2 (100 ft 2 /in 2 ) to get the total usable floor space (m 2 [ft 2 ]) served by the raceway. Raceway area (cm 2) Raceway area (in 2) x 1.54 (m 2/cm 2) x 100 (ft 2/in 2) Floor area served (m 2) Floor area served (ft 2) Print Search Search Find 6 2 Divide the floor area served (m [ft ]) by the width of the area served by the raceway to determine the allowable length of floor area that the raceway can serve. Floor area served (m 2) ÷ Floor width served (m) Allowable length served (m) 7 2 Floor area served (ft 2) ÷ Floor width served (ft.) Allowable length served (ft.) Find Quit Select and compute the floor space which can best be served directly from the telecommunications closet (without raceways). 259 Conduit and Raceway Design for Ceiling Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Designing a Ceiling Raceway System, continued Help Step Designing A Ceiling Raceway System TOC 8 Select the general location of feeder raceways extending from the telecommunications closet. Print 9 Use the following equation to determine the minimum crosssectional area required for the feeder raceways extending from the telecommunications closet: Floor area served (m 2) Floor area served (ft 2) ÷ 1.54 (m 2/cm 2) ÷ 100 (ft 2/in 2) Raceway cross-sectional Raceway cross-sectional 2 area (cm ) area (in 2) Allot feeds from the telecommunications closet to the distribution raceways. 10 NOTE: 11 Search Search Find Find Quit The cable capacity of each feeder must be greater than or equal to the anticipated work area requirements of the floor space it serves. Provide insets, sketches, notes, and other labeling and documentation required for the proper construction and administration of distribution pathways and spaces (Reference ANSI/TIA/EIA-606). 260 Cabling Guidelines for Ceiling Pathways Managing Cabling Cabling Guidelines Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems for Ceiling Pathways Help In order to effectively manage the cabling of a suspended ceiling distribution system, follow the steps in the procedure below. TOC Connecting hardware must be mounted in locations that are readily accessible. Mounting of certain types of hardware (i.e., consolidation point connectors) in a suspended ceiling space may be acceptable, provided that: Print • The space is accessible. Search • Building fixtures, equipment or heavy furniture (e.g., file cabinets weighing 45 kg [100 lb] or more) do not compromise access. Find • Access does not disturb building occupants. • Hardware is protected from physical abuse and foreign substances. In all cases, the use of connecting hardware in ceiling spaces shall conform to ANSI/ NFPA 70 (in Canada, refer to the applicable CSA requirements) and local building codes. Telecommunications outlet/connectors must not be located in the ceiling space. CAUTION: Do not place connecting hardware (e.g., 25-pair connectors, adapters) or telecommunications equipment in the ceiling or access floor space. The only allowable exception is for connecting hardware as part of a consolidation point. (See “Consolidation Point” in this chapter for recommendations and guidance.) Search Find Quit 261 Cabling Guidelines for Ceiling Pathways Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Managing Cabling, continued Help Step TOC Designing A Ceiling Raceway System 1 Pull or place cables into the zone pathway. 2 Leave sufficient slack in the ceiling to reach any work area outlet within the zone. Print Search 3 Where zone pathways are not provided, divide the floor area into direct-run telecommunications zones. Search 4 Run all the cables to the center point of their zones. Find 5 From the center point of each zone, distribute the cables to work areas within that zone. Find 6 At the center point of each telecommunications zone, support all cables with a cable tie or similar device. Quit NOTE: Tightly cinched cable ties have a detrimental effect on transmission performance and should be avoided. 262 Cabling Guidelines for Ceiling Pathways Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Managing Cabling, continued Help Step Designing A Ceiling Raceway System TOC Coil any cable that is not in service back to the end of the zone pathway. When required, cable tie these coiled cables. Print WARNING: Carefully handle cables to avoid damage. Search 7 8 Label the cables and pathways for easy recognition and establish a working data base for ongoing identification and maintenance of horizontal cables and pathways (Reference ANSI/TIA/EIA-606). Search Find Find Quit 263 Work Area Distribution for Ceiling Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Utility Columns Work Area Distribution for Ceiling Systems Help A utility column is a post used by a ceiling distribution system. Utility columns: TOC • Extend from the suspended ceiling support channel to the floor. Print • Conceal telecommunications cabling from the ceiling to the desks. Search • Serve as an extension for power outlets to desk locations. Utility columns that are used for both telecommunications and power distribution must be equipped with a barrier and must comply with applicable electrical codes. When a metallic barrier is used, it must be bonded to ground. Damaging Support Channels Search Find Find Quit Depending on their design and the care with which they are installed, utility columns may be subject to slight shifts during and after placement. These shifts can cause a support channel to become warped, marred, or bent. Excessive bending of support channels may cause ceiling panels to fall down. 264 Work Area Distribution for Ceiling Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Concealing Cables in Walls or Partitions Help When plans show ceiling cables concealed behind walls or partitions, the concealment requires a: TOC • Unimpeded vertical channel a minimum of 2 cm (0.75 in.) wide and deep. Print • Pull wire. Search The space permits the cable to pass from the outlet box to the top of the wall. Search NOTES: Find • Within the wall or partition, run trade size ¾ conduit to the outlet box. • Provide a 2-cm by 2-cm (0.75-in. by 0.75-in.) clear space between partition sections that have snap-in panels or covers. Find Quit 265 Work Area Distribution for Ceiling Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Attaching Utility Columns Help Attach utility columns to the main ceiling support channels. The main ceiling support channels must be rigidly installed and braced to prevent both vertical and horizontal movement. TOC NOTE: Utility columns may be attached to the transverse (cross) rails only if these rails are securely anchored to the main ceiling support channel. Search Several utility columns and their attachments to the ceiling or ceiling fixtures are shown in the following illustrations: Search Print Find Find Quit 266 Work Area Distribution for Ceiling Systems Attaching Utility Columns, continued Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Help Telecommunications Cable TOC Hanger Clamp Print Suspended T-Bar Ceiling Figure 4.40: Attaching utility columns Search Search Utility Column Find Type A Type B Type C Type D Type E Type F Find Covers are available for coaxial, twin axial, RS-232 and twisted pair telephone connectors. Quit 2 1/8 in. - + 2 3/4 in. 2 1/4 in. 2 in. 2 3/4 in. 27/8 in. 21/8 in. 17/16 in. 2 in. 2 1/4 in. 267 Work Area Distribution for Ceiling Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Attaching Utility Columns, continued Help Figure 4.40: Attaching utility columns, continued TOC NOTES: Multiply inches by 2.54 to convert to centimeters. Utility poles project through the suspended ceiling and connect to the overhead cabling system. Standard poles accommodate 3.1 m (10 ft.), 3.7 m (12 ft.), and 4.6 m (15 ft.) ceiling heights and mount rigidly between the ceiling support channel grid and carpeted or tiled floor. Types D, E, and F can be fitted with an additional snap-on compartment for increased telecommunications cabling needs. Covers are removable for lay-in of telecommunications cabling. Telecommunications outlets are on the sides or bottom. All poles are safety listed. Utility columns that attach directly to modular furniture or partitions are also available. Because these types of columns are structurally integral, they blend into the office environment, are well supported, and offer increased flexibility due to their ability to conceal and support horizontal cabling that is routed directly to cable troughs and outlet receptacles in the modular furniture. Print Search Search Find Find Quit 268 Other Pathways (Miscellaneous) Introduction Other Pathways Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems (Miscellaneous) Other types of pathways include: • Perimeter raceway systems (metal and wood). • • Weather resistant. Overfloor ducts. • Molding raceways. • Open office distribution systems. Perimeter, overfloor, and molding raceway systems are typically not used to any great extent in new buildings. However, they may be appropriate for building renovations (especially older structures) and other special uses. Perimeter raceways, molding raceways, overfloor ducts, and open office distribution systems are limited to use only in dry locations. To determine the size of these pathways, use the: • Help TOC Print Search Search Find Find Quit Manufacturer’s recommendations. or • Guidelines in “Sizing of Horizontal Pathways” in this chapter. These pathways must not have any sharp edges; provide bushings to cover any sharp edges. Do not route these pathways through gaps in the floor structure, the ceiling structure, the curtain wall, or any other penetration where a firestop barrier is required. 269 Other Pathways (Miscellaneous) Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Perimeter Raceway Systems Help Perimeter raceways are available in: TOC • Plastic, metal or wood. • Recessed or surface-mounted designs. • Baseboard or chair-rail heights. In most designs: • The front panel is removable. • Outlets may be placed at any point along the run and may be moved or added after initial installation. In a perimeter raceway, power and telecommunications services must be run in separate compartments and must comply with applicable electrical codes. When a metallic barrier is provided, it must be bonded to ground. Print Search Search Find Find Quit 270 Other Pathways (Miscellaneous) Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Perimeter Raceway Systems, continued Help The assignment of raceway compartments to either telecommunications or electrical power circuits must be consistent throughout the premises. TOC Perimeter raceway systems are similar in design to the raceway systems provided with open office (also called “modular”) furniture systems. Much of the distribution methodology used for perimeter raceway systems may also be applied to open office furniture systems. When these systems are used to distribute and conceal horizontal cabling (as with movable partitions), the pathways must be accessible via a snap-in panel or removable covers. For further information, see “Open Office Distribution Systems” in this chapter. Print Search Search Find Find Quit 271 Other Pathways (Miscellaneous) Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Using Perimeter Raceway Systems LAN Adapter Cover Use perimeter raceways primarily for small floor areas where the majority of telecommunications service will be along the walls, as shown in the following illustration. Figure 4.41: Perimeter raceway Combination Duplex Receptacle and Telecommunications Outlet Cover Perimeter Raceway System Provides Both Premises and Power Wiring at Baseboard level. - + Divided Raceway - WallMounted at Desk Height With Voice and Data Telecommunication and Power Outlet Spaced as Needed. Recessed Divided Raceway Forms Flush Baseboard. Help TOC Print Search Search Find Duplex Telecommunications Outlet Quit Building Perimeter Distribution System Provides Convenience Outlets (Telecommunications and Power) in Larger Office Areas. - + Divided Raceway Runs in Smaller Offices Are Either Back-Connected Through Partitions or Built into Modular Furniture. Find Modular Furniture Partitions are Attached Anywhere Along Perimeter Raceway. 272 Other Pathways (Miscellaneous) Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Overfloor Ducts Help Overfloor ducts are used to carry exposed cabling across floor surfaces. Overfloor ducts can be made of metal, rubber, or plastic. TOC A metal overfloor duct consists of a: Print • Base which is secured to the floor. Search • Cover which is fastened to the base after the cabling is installed. Search A rubber overfloor duct consists of lengths of specially molded rubber which are cemented to the floor. Find Find Quit 273 Other Pathways (Miscellaneous) Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Molding Raceways Help The types of molding raceways include: TOC • Large picture molding for use in rooms. • Large wood or eaves trough metal moldings for use in hallways. Print Search Place sleeves in the walls to connect room and hall moldings. Use conduits to connect hallway moldings to work area locations. Generally this type of installation is outdated. However, it is acceptable in some apartments, hotels, etc., if the moldings are accessible from the work area, as shown in the following illustration. Figure 4.42: Molding raceways Search Find Find Room Moulding Quit Hall Moulding Conduit Nipple Reamed Ends - + 274 Other Pathways (Miscellaneous) Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Open Office Distribution Systems Help In large rooms designed for open office use, cabling pathways are often provided in the partitions and furniture which form office clusters. These partitions and furniture provide continuous pathways to telecommunications outlets, work area equipment, or both. TOC In a properly designed open office, the pathway design: • • Provides for power separation and cable access (see the guidelines for perimeter pathways). Provides for accepting horizontal building cabling from pathways that enter the work area. • Protects the cabling components from physical damage during normal use. • Allows for proper cable management and termination, including the work area cables. • Provides adequate space for the number of outlets and users served. • Includes accessible locations and secure mounting provisions for telecommunications outlet/connectors. • Meets all applicable safety and regulatory requirements. Print Search Search Find Find Quit 275 Other Pathways (Miscellaneous) Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Open Office Distribution Systems, continued Help When installing and using these types of horizontal pathways, always follow the manufacturer ’s instructions. For further information about recommended implementations of open office cabling, see “Open Office Cabling Systems” in this chapter. TOC Print Search Search Find Find Quit 276 Telecommunications Closets Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Overview Help Telecommunications Closets Telecommunications closets are dedicated telecommunications distribution TOC facilities designed to be accessed by flexible, high-density horizontal distribution systems in floors and ceilings to work areas. The design of telecommunications closets depends upon the: • Size of the building. • Number of floors. • Tenant characteristics. • Telecommunications services used. The design and contents of the telecommunications closet must comply with the requirements explained in Chapter 6, “ Telecommunications Closets and Rooms.” Print Search Search Find Find Quit 277 Outlet Boxes Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Wall-mounted Outlets Help Telecommunications outlet boxes installed in a dry-wall, plaster, or concrete block wall must be at least 5 cm by 7.5 cm by 6.4 cm deep (2 in. by 3 in. by 2½ in. deep). However, to allow space for cable management and future growth, an outlet box that is at least 10 cm sq. by 6.4 cm (4 in. sq. by 2½ in. deep) is recommended, especially where 2.7 cm (1 in.) conduit is used. Specialty boxes that provide an equivalent amount of space may also be used, as required. TOC For installations that use a single-gang faceplate to mount two or more telecommunications outlet/connectors, provide the desired cable slack and bend radii by installing a double gang box (10 cm by 10 cm [4 in. by 4 in.]) behind a wall opening that is sized for a single gang faceplate (5 cm by 10 cm [2 in. by 4 in.]). Search NOTE: Plaster rings are not suitable for securing connectors in the ser vice location, especially when conduits rise from the floor. Quit Outlet Boxes Print Search Find Find Outlet boxes that are placed back-to-back to serve adjacent rooms can compromise the effectiveness of the wall as a sound barrier. When possible, offset the box locations and interconnect them with conduit. For information on the requirements for pathways, outlet boxes, and mounting for public telephones, see Chapter 18, “Miscellaneous and Special Situations.” 278 Outlet Boxes Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Cover Plates Help Provide a suitable cover plate for all telecommunications outlet boxes. Cover plates for wall-mounted outlets must be designed to fit one-gang or twogang outlet boxes. TOC Larger Outlet Boxes Search Print The space provided by a 10-cm (4-in.) square box may not be adequate if: Search • Conduits are multiplied (branched) in it. Find • Key telephone system cables are looped through. Find In these cases, use a larger box. Quit 279 Outlet Boxes Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Mounting Telecommunications Outlets on Walls Help Follow the guidelines below when mounting telecommunications outlet/ connectors on walls. For walls with: TOC • Print • No obstructions for a width of at least 76 cm (30 in.), mount outlet/connectors 38 cm (15 in.) to 122 cm (48 in.) from the finished floor (front reach). No obstructions of greater than 25 cm (10 in.) deep for a width of at least 122 cm (48 in.), mount outlet/connectors a distance of 23 cm (9 in.) to 137 cm (54 in.) from the finished floor (side reach). NOTE: When it is desirable to conceal the outlet box behind surfacemounted telecommunications equipment (i.e., a telephone), the standard mounting height is 122 cm (48 in.) from the finished floor to the center of the outlet box, provided that the location has no obstruction greater than those specified in the preceding bullets. Search Search Find Find Quit To provide uniform appearance and accessibility in the work area, it is desirable to mount telecommunications outlet boxes at the same height as the outlet boxes that provide electrical power. 280 Outlet Boxes Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Mounting Telecommunications Outlets on Walls, continued Help It is recommended that the entire faceplate area of telecommunications outlet boxes be installed to meet the specifications above. For example, the height of the lower inside surface of the outlet box should be no less than 38 cm (15 in.) above the finished floor. TOC NOTE: For information about ensuring that disabled individuals have access to telecommunications outlet/connectors, see Chapter 18, “Miscellaneous and Special Situations.” Chapter 18 also provides guidelines for locations that do not meet the conditions described above. Print Search Search Find Find Quit 281 Outlet Boxes Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Mounting Outlets Above Counters and Cabinets Help Follow the guidelines below when mounting outlet/connectors above counters and cabinets. Mount outlet/connectors: TOC • Print 122 cm (48 in.) or less above the finished floor for surfaces which are behind counters which are: – No more than 51 cm (20 in.) deep. – No less than 76 cm (30 in.) wide. The space below the counter must be unobstructed to provide leg access (i.e., front reach). • 112 cm (44 in.) or less above the finished floor for surfaces which are behind counters which are: Search Search Find Find Quit – Between 51 cm (20 in.) and 64 cm (25 in.) deep. – No less than 76 cm (30 in.) wide. The space below the counter must be unobstructed to provide leg access (i.e., front reach). 282 Outlet Boxes Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Mounting Outlets Above Counters and Cabinets, continued Help • 117 cm (46 in.) or less above the finished floor for surfaces which are behind counters and cabinets which are: TOC – No more than 61 cm (24 in.) deep. Print – No more than 87 cm (34 in.) tall. Search – No less than 122 cm (48 in.) tall. The space below the counter may only be obstructed up to the depth of the counter/cabinet (side reach). NOTE: For information about ensuring that disabled individuals have access to telecommunications outlet/connectors, see Chapter 18, “Miscellaneous and Special Situations.” Chapter 18 also provides guidelines for locations that do not meet the conditions described above. Search Find Find Quit 283 Undercarpet Telecommunications Cable (UTC) Introduction Undercarpet Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Telecommunications Cable (UTC) Undercarpet Telecommunications Cable (UTC) is a flat, low-profile cable designed to be installed directly on the surface of a floor and covered with carpet or carpet squares (carpet tiles). Carpet tiles are recommended to ensure access to the UTC. UTC is available in: • Unshielded pairs. • Shielded pairs. • Coaxial. • Fiber. Because of the many limitations of UTC systems, they are not generally recommended for horizontal cabling distribution (see “Advantages of Undercarpet Telecommunications Cable [UTC]” and “Disadvantages of Undercarpet Telecommunications Cable [UTC]” in this chapter). However, because UTC does offer advantages for some applications, guidelines for its use are provided. Help TOC Print Search Search Find Find Quit 284 Undercarpet Telecommunications Cable (UTC) Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Using UTC Help UTC may be used as a part of the horizontal distribution system when other distribution systems are not feasible. UTC should be implemented as a part of a zone distribution system, where cable runs are restricted to a limited area and serviced by one or more distribution points within or along the perimeter of the area served. TOC Using the zone approach in a typical 9-m by 9-m (30-ft. by 30-ft.) area can: Search • Keep undercarpet cable runs short (usually 10 m [33 ft.] or less). • Limit disruptions due to service changes to a small area of the office. Print Search Find Find Quit 285 Undercarpet Telecommunications Cable (UTC) Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems UTC Restrictions Help Do not use UTC: TOC • Unless the UTC cables and connectors meet all applicable requirements of ANSI/TIA/EIA-568-A (in Canada, CSA T529). Print • In wet locations. Search • Where the cable might come in contact with chemicals or solvents. CAUTION: UTC connecting hardware and cabling may not be compatible with high performance UTP cabling. Check the transmitting capability of all UTC components before use. Search Find Find Quit 286 Undercarpet Telecommunications Cable (UTC) Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Reversing the Direction of UTC Help The following illustration shows the correct way to reverse the direction of UTC cable. TOC Figure 4.43: Reversing direction of UTC Print Search Search Find Find Quit - + 287 Undercarpet Telecommunications Cable (UTC) Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Prerequisites for Installing UTC Help Before installing UTC, ensure that: TOC • Flat power cable is already installed in the same area. • Work area locations have been finalized. • Other construction activities are complete. ( This reduces the possibility of damage to the cable.) Print Search Search Find Find Quit 288 Undercarpet Telecommunications Cable (UTC) Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Preparing the Floor Surface Help CAUTION: Do not install UTC until: TOC • The floor is properly prepared. • All construction work is finished. Follow the steps in the following table to make sure the floor is prepared before installing UTC. Step Preparing The Floor Surface 1 Repair any holes in the floor surface. 2 Clear away any grit or sharp-edged particles that could penetrate the cable. 3 Print Search Search Find Find Quit Smooth the rough concrete floor. If the floor surface cannot be made smooth, apply metallic armored tape beneath the UTC. NOTE: Always use undertaping when installing UTC. 289 Undercarpet Telecommunications Cable (UTC) Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Storing UTC Help The following illustrations show methods of storing UTC. TOC Figure 4.44: Storing UTC in folds in the floor fitting Print Search Search - + Find Find Figure 4.45: Storing UTC in coils Quit - + 290 Undercarpet Telecommunications Cable (UTC) Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Storing UTC, continued Help Figure 4.46: Storing UTC in undercarpet folds TOC Print Search Search - + Find Find Quit 291 Undercarpet Telecommunications Cable (UTC) Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Using UTC with Undercarpet Power Cables Help UTC is often used in conjunction with undercarpet power cable. Design the cabling so that undercarpet power cables and UTC will feed into a distribution area from opposite ends. This reduces the number of times they must cross each other. TOC When UTC and undercarpet power cables are used in the same area, a power cable must never: • Run parallel to a UTC at a distance of 15 cm (6 in.) or less. • Cross over a UTC. NOTE: A UTC may cross over a power cable, if necessar y, but the layout should be designed to require as few crossovers as possible. Print Search Search Find Find Quit 292 Undercarpet Telecommunications Cable (UTC) Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Designing a Layout Using UTC Help Follow the steps in the following table to design a layout using UTC. TOC Step Designing A Layout Using Undercarpet Telecommunications Cable Print 1 Identify the characteristics of the floor space. Search 2 Establish the standards on which to base the design. Search 3 Calculate the usable floor area to be served in: 4 • Distinctive segments. Find • Total. Find Locate and identify: • Zone conduits. • Transition boxes so as to minimize crossovers with electrical power UTC. NOTE: Plan transition box locations so that each box serves a usable floor area no larger than 80 m2 (800 ft 2 ), based on the guideline of one work area per 10 m 2 (100 ft 2 ) of usable floor space. Quit 293 Undercarpet Telecommunications Cable (UTC) Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Designing a Layout Using UTC, continued Help Step TOC 5 Designing A Layout Using Undercarpet Telecommunications Cable Print Identify : • Work area locations. • Types of work areas. • Specific groups of work areas. 6 Select the route from the telecommunications closet to each set location. 7 Select a distribution system to use up to the point where the transition to UTC will be made. NOTE: Search Search Find Find Quit From the transition point on, the UTC must: • Meet the applicable performance requirements for the media used. • Connect to telecommunications outlet/connectors that conform to the requirements provided under “Horizontal Cable and Connecting Hardware” in this chapter. 294 Undercarpet Telecommunications Cable (UTC) Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Designing a Layout Using UTC, continued Help Step TOC 8 Designing A Layout Using Undercarpet Telecommunications Cable Prepare all necessary sketches and notes to: • Print Indicate: Search – Location. Search – Measurements. – Abnormal situations. – Reference to building constants. • Assist in installing all components of the cable system from the telecommunications closet to the work area equipment. Find Find Quit 295 Undercarpet Telecommunications Cable (UTC) Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Transition Points in Columns Help The following illustration shows transition points in columns in a UTC layout. TOC Figure 4.47: Transition points Print Search Zone Telecommunications Zone Conduits or Cable Bundles in Ceiling Plenum Search Zone Find Core Area Zone Zone Core Area Transition Point Zone Zone Find Telecommunications Closet Quit Columns - + 296 Undercarpet Telecommunications Cable (UTC) Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Transition Box Guidelines Help Locate transition boxes in permanent structures (e.g., building columns, structural walls, flush floor boxes). Do not locate transition boxes in walls that might be relocated. Choose transition box locations that minimize crossovers of electrical and telecommunications UTC. TOC To provide access to the floor surface, place the box in the wall cavity with its bottom open. Mount the transition box 2.5 cm to 7.5 cm (1 in. to 3 in.) above the floor, with its finished cover abutting the top of the baseboard molding. Ensure that the wall has a cutout that is matched to the width of the box and extends from the floor to the upper inside wall of the box. When determining the size of the horizontal pathways that feed transition boxes, consider the size of the area served and the guidelines provided for the type of pathway used. Print Search Search Find Find Quit 297 Undercarpet Telecommunications Cable (UTC) Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Transition Box Sizes Help The following sizes are recommended for UTC transition boxes for a variety of cable quantities and types: TOC Print Table 4.24: Recommended sizes Search Search Find Find - + Quit 298 Referenced Standards Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Chapter 4 - Horizontal Cabling Systems Introduction Referenced Standards Efforts have been made to harmonize the requirements and recommendations in this chapter with ANSI (American National Standards Institute) approved telecommunications cabling standards, as well as regulatory and safety standards pertaining to telecommunications networks. However, the distribution designer is responsible for acquiring a working knowledge of these standards and actively using them. Help TOC Print Search Search Find Find Quit 299 Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Referenced Standards Chapter 4 - Horizontal Cabling Systems Standards and Specifications Help The standards and specifications that have been referenced in this chapter are listed below: TOC Print Table 4.25: Standards Ref : Specification: Title: Search 4.1 ANSI/NFPA 70 The National Electrical Code ® , (in Canada, see specification CSA C22.1, The Canadian Electrical Code, Part 1) Search Commercial Building Telecommunications Cabling Standard (in Canada, see specification CSA T529) Find 4.2 ANSI/TIA/EIA-568-A 4.3 ISO/IEC 11801 Generic Cabling for Customer Premises 4.4 CENELEC EN 50173 Performance Requirements for Generic Cabling Schemes Find Quit 300 Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Referenced Standards Chapter 4 - Horizontal Cabling Systems Standards and Specifications, continued Help Table 4.25: Standards, continued TOC Ref : Specification: Title: 4.5 ANSI/TIA/EIA-606 Administration Standard for the Telecommunications Infrastructure of Commercial Buildings (in Canada, see specification CSA T528) 4.6 ANSI/TIA/EIA-607 Print Search Search Commercial Building Grounding and Bonding Requirements for Telecommunications (in Canada, see specification CSA T527) Find Quit 4.7 TIA/EIA TSB75 Additional Horizontal Cabling Practices For Open Offices 4.8 IEC 603-7, Part 7 Detail Specification for Connectors, 8-Way, Including Fixed and Free Connectors with Common Mating Features Find 301 Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Referenced Standards Chapter 4 - Horizontal Cabling Systems Standards and Specifications, continued Help Table 4.25: Standards, continued TOC Ref : Specification: Title: 4.9 FIPS PUB 174 Commercial Building Telecommunications Wiring Standard. Federal Information Processing Standard Publication Print Search Search 4.10 UL 444 and 13 Adopted Test and Follow-Up Service Requirements for the Optional Qualification of 100-Ohm Twisted-Pair (Cables) Find Find 4.11 4.12 IEC 807-8 ISO/IEC 8802-5 Rectangular Connectors for Frequencies Below 3 MHz, Part 8: Detail Specification for Connectors, Four-Signal Contacts and Earthing Contacts for Cable Screen, First Edition Quit Token-ring Access Method and Physical Layer Specifications 302 Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Referenced Standards Chapter 4 - Horizontal Cabling Systems Standards and Specifications, continued Help Table 4.25: Standards, continued TOC Ref : Specification: Title: 4.13 IEC 874-14 Sectional Specification for Fiber Optic Connector Type SCFOC/2.5 4.14 IEC 874-10 Sectional Specification for Fiber Optic Connector Type BFOC/2.5 4.15 TIA/EIA TSB67 Transmission Performance Specifications for Field Testing of Unshielded Twisted-Pair Cabling Systems 4.16 ANSI/TIA/EIA-569-A Commercial Building Standard for Telecommunications Pathways and Spaces (in Canada, see CSA T530) 4.17 ASTM 84-80 Surface Burning Characteristics of Building Materials Print Search Search Find Find Quit 303 Telecommunications Distribution Methods Manual on CD-ROM, 8th edition, © 1998 BICSI ® Referenced Standards Chapter 4 - Horizontal Cabling Systems Standards and Specifications, continued Help Table 4.25: Standards, continued TOC Ref : Specification: Title: 4.18 NFPA 255 Surface Burning Characteristics of Building Materials (in Canada, see the National Building Code) Print Search Search 4.19 CISCA Recommended Test Procedures for Access Floors Find Find Quit 304 Chapter 4 Horizontal Cabling Systems Telecommunications Distribution Methods Manual on CD-ROM, 8th edition Continue
