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INDUSTRIAL EXPLOSION PROTECTION Fenwal
FENWAL Protection Systems INDUSTRIAL EXPLOSION PROTECTION presented by Fenwal Protection Systems Fenwal Protection Systems Proprietary FENWAL Fenwal Protection Systems Protection Systems • Part of UTC Fire and Safety, largest fire and explosion protection company in the world • Explosion Suppression • Explosion Isolation • Explosion Venting • Material Evaluation (Combustion Research Center) Fenwal Protection Systems Proprietary FENWAL Protection Systems Industries at Risk • • • • • • • • • Chemical Petrochemical Grain Food Pharmaceutical Aerosol Steel Cement Wood Fenwal Protection Systems Proprietary 1 FENWAL Deflagrations - What Happens Protection Systems • • • • Flame Speed 30 ft/s Pressure Wave 1100 ft/s Secondary Explosions Flame Propagation Fenwal Protection Systems Proprietary FENWAL Protection Systems Deflagration Pressure vs. Time 120 110 100 90 VESSEL: 1.9 M3 DUST: DRY STARCH DUST CONC.: 1000 G/M3 IGNITION ENERGY: 5 KJ 80 70 PRESSURE 60 PSIG 50 40 30 20 IGNITION 10 0 PNEUMATIC DUST INJECTION 0 0.2 TIME, SEC. 0.4 Fenwal Protection Systems Proprietary FENWAL Protection Systems Explosibility Calculation Pressure Pmax Kst = R max V1/3 [bar-m/s] Where Rmax dP dt Rmax = The maximum rate of pressure rise [bar/s] V = The volume of the test vessel [m3] Rmax = (dP/dt)max Time Fenwal Protection Systems Proprietary 2 FENWAL Protection Systems ST Classification and Kst ST Classification ST - 1 ST - 2 ST - 3 Kst Value 1 -200 201 - 300 301 and above Example - Pittsburgh seam coal has a Kst value of 129 bar m/s it is therefore considered an ST - 1 dust. Fenwal Protection Systems Proprietary FENWAL Protection Systems NFPA and Explosion Protection Applicable Codes (USA) • NFPA 654 Combustible Particulate Solids • NFPA 664 Wood Processing • NFPA 61 Agricultural and Food Products • NFPA 30B Aerosol Products • NFPA 484 Combustible Metals • NFPA 68 Venting of Deflagrations • NFPA 69 Explosion Prevention Systems Fenwal Protection Systems Proprietary FENWAL Protection Systems OSHA Combustible Dust Directive • Chemical Safety Board – – – – – Independent Federal Agency 1998 Investigates industrial chemical accidents Determines and reports root cause 2003 investigate three fatal dust explosions These events led to a 2005/2006 commission to study dust explosion Fenwal Protection Systems Proprietary 3 FENWAL Protection Systems Chemical Safety Board Findings Study Findings – 300 dust explosions over 25 year period – 119 fatalities, almost 800 injured – MSDS for combustible dusts do not contain explosion hazard information – US safety regulations do not address dust explosion mitigation requirements – Consensus standards provide guidance, but are voluntary unless adopted by state or local AHJs – OSHA responsible per General Duty Clause requiring safe and healthful workplace Fenwal Protection Systems Proprietary FENWAL Combustible Dust National Emphasis Program Protection Systems http://www.osha.gov/OshDoc/Directive_pdf/CPL_03-00-008.pdf Fenwal Protection Systems Proprietary FENWAL Protection Systems OSHA Directive CPL 03-00-008 National Emphasis Program on Combustible Dusts “Purpose. This instruction contains policies and procedures for inspecting workplaces that handle combustible dusts that are likely to cause dust deflagrations, other fires, or explosions. These dusts include, but are not limited to: • Metal dust such as aluminum and magnesium. • Wood dust • Coal and other carbon dusts • Plastic dust and additives • Biosolids • Other organic dust such as sugar, paper, soap, and dried blood. • Certain textile materials.” Fenwal Protection Systems Proprietary 4 FENWAL Protection Systems OSHA Directive CPL 03-00-008 National Emphasis Program on Combustible Dusts – – – – – – – General Duty Clause requiring safe and healthful workplace Issued 10-18-2007, updated March 2008 Testing samples for combustibility Explosion mitigation requirements per NFPA 654 Deflagration isolation required per NFPA 654 Reviewing housekeeping (1/32”) Citations and Fines Fenwal Protection Systems Proprietary FENWAL Protection Systems OSHA Fact Sheet and Poster Fenwal Protection Systems Proprietary FENWAL Protection Systems Explosion Protection Methods • Containment • Inerting • Deflagration Relief Venting • Deflagration Suppression • Deflagration Isolation Fenwal Protection Systems Proprietary 5 FENWAL Containment Protection Systems • Withstand Maximum Deflagration Pressure • ASME Pressure Vessel Code • Initial Pressure 30 psig max. • NFPA 69 Fenwal Protection Systems Proprietary FENWAL Protection Systems Containment Vessel Fenwal Protection Systems Proprietary FENWAL Protection Systems Inerting • Lowering Oxygen Concentration • Inert Gases: Nitrogen, Carbon dioxide, Argon • NFPA 69 Fenwal Protection Systems Proprietary 6 FENWAL Min. Safe Oxygen Concentration Protection Systems Dusts Aluminum Propane Hydrogen 9 - 16% 5 11 5 Use data for determining inerting system design Fenwal Protection Systems Proprietary FENWAL Max. Pressure vs. Oxygen Concentration 6 5 4 3 . 1 2 Pressure Bar Ga 8 7 9 Protection Systems 8 10 12 14 16 18 20 22 Oxygen Concentration (Vol. %) Fenwal Protection Systems Proprietary FENWAL Protection Systems Deflagration Relief Vents •Rupture-style •flat or domed •Square or rectangular •Optional burst sensors Fenwal Protection Systems Proprietary 7 FENWAL Protection Systems Vented Dust Explosion •Fireball 7x volume of vessel •Flame ejection >50’ •Must vent to safe area •Combustible must be safe to vent outside Fenwal Protection Systems Proprietary FENWAL Vented Explosion Protection Systems Pressure-Time Graph Pmax Pressure Unvented Strength of Vessel P red - Vented Deflagration Pressure Pstat - Vent Opening Pressure Vented Time Fenwal Protection Systems Proprietary FENWAL Protection Systems Vented Dust Explosion Venting of Inside Vessels • Ducts less than 6 meters • Ducts straight (no bends) • Ducts strength sufficient • Additional vent area/vessel strength required Fenwal Protection Systems Proprietary 8 FENWAL Flameless Explosion Vents Protection Systems Fenwal Protection Systems Proprietary FENWAL Protection Systems Flameless Explosion Vents • Passive protection means • Decreases the energy emitted from a vented deflagration • Allows inside venting to be performed without vent ducts • Temperatures cooled to approx. 900 C • Burst sensor for signaling activation Fenwal Protection Systems Proprietary FENWAL Protection Systems Explosion Suppression Fenwal Protection Systems Proprietary 9 FENWAL Protection Systems Explosion - Unsuppressed vs. Suppressed Fenwal Protection Systems Proprietary FENWAL Protection Systems Deflagration Suppression PRESSURE, PSIG DEFLAGRATION SUPPRESSION: P Vs TIME VESSEL: 1.9 M3 DUST: DRY STARCH DUST CONC.: 1000 G/M3 IGNITION ENERGY: 5 KJ 5 4 SUPPRESSION 3 AGENT: SODIUM BICARBONATE HRD DISCHARGE 2 DETECTION P: 0.5 PSIG IGNITION 1 0 -1 0 PNEUMATIC DUST INJECTION 0.2 TIME, SEC. 0.4 Fenwal Protection Systems Proprietary FENWAL Protection Systems Explosion Suppression Components Control Unit Explosion Pressure Detectors Explosion Suppression Extinguisher Fenwal Protection Systems Proprietary 10 FENWAL Protection Systems Explosion Pressure Detector Static or Dynamic Detector • S/s diaphragm • Field adjustable • Paired sensors for false alarm safeguard • Often mounted with standoffs for vibration isolation Fenwal Protection Systems Proprietary FENWAL Protection Systems Control Unit •Microprocessor-controlled •NEMA 4 Enclosure •Wall-Mount •Keyswitch Arming/Disarming •self-diagnostic LED indicators for alarm and trouble conditions •includes battery backup •Equipment Interlocking Fenwal Protection Systems Proprietary FENWAL Protection Systems Explosion Suppression Extinguisher • Sodium-bicarbonate agent • Used for suppression and chemical explosion isolation • Supervised, integral OSHA lockout/tag-out plate. • Dust-ignition proof, weatherproof NEMA enclosure. • DOT/TC approved. • Nitrogen pressurized at 900 psi Fenwal Protection Systems Proprietary 11 PistonFire - Discharge FENWAL Protection Systems Fenwal Protection Systems Proprietary Computer Model FENWAL Protection Systems •Vessel Volume •Length/Diameter Ratio •Explosivity Characteristics – KST, PMAX, AIT •Detection Setpoint •Extinguisher Orientation •Style of HRD •Type of Suppressant •Volume of Suppressant •Agent Throw Fenwal Protection Systems Proprietary FENWAL Protection Systems Explosion Propagation Fenwal Protection Systems Proprietary 12 FENWAL Protection Systems Explosion Isolation •NFPA 68 •NFPA 654 •Mechanical Isolation •Chemical Isolation Fenwal Protection Systems Proprietary FENWAL Protection Systems Active Explosion Isolation Chemical Explosion Isolation Mechanical Isolation Valve Fenwal Protection Systems Proprietary FENWAL Protection Systems Explosion Isolation Barriers Fenwal Protection Systems Proprietary 13 FENWAL Protection Systems Detection – Recirculated Exhaust •Must stop transmission of explosion or fire if exhaust is recycled back into plant per NFPA 654 •Explosion detector on vessel, IR flame detector on exhaust •Mechanical or chemical isolation Fenwal Protection Systems Proprietary FENWAL Protection Systems Collector Passive Explosion Isolation Fenwal Protection Systems Proprietary FENWAL Protection Systems Explosivity Testing • • • • • • Dust cloud reactivity (Pmax and Kst) Dust cloud minimum ignition temperature Dust layer minimum ignition temperature dust cloud minimum ignition energy Minimum explosible dust concentration Minimum safe oxygen concentration 20-Liter test vessel for Kst, Pmax determination Go-No Go Test Fenwal Protection Systems Proprietary 14 FENWAL Protection Systems Explosion Risks – Process Areas Fenwal Protection Systems Proprietary FENWAL Protection Systems Dust Collectors - Baghouses Active Suppression and Isolation Passive – Venting and Inlet Isolation Fenwal Protection Systems Proprietary FENWAL Protection Systems Air Separation Vessels - Cyclones Fenwal Protection Systems Proprietary 15 FENWAL Protection Systems Mills/Pulverizers Baghouse Cyclone Mill Fenwal Protection Systems Proprietary FENWAL Protection Systems Spray Dryers Fenwal Protection Systems Proprietary FENWAL Protection Systems Fluid Bed Dryers Fenwal Protection Systems Proprietary 16 FENWAL Silos/Hoppers Protection Systems Fenwal Protection Systems Proprietary Bucket Elevator FENWAL Protection Systems Fenwal Protection Systems Proprietary FENWAL Protection Systems • • • • • Combustible Vapor - Manned Chemical Storage Rooms Chemical Mixing Rooms Aerosol Fill Rooms/Gashouses Hydrocarbon Gas Filling Hydrocarbon Reclaim Areas Fenwal Protection Systems Proprietary 17 FENWAL Protection Systems System Inspections and Support • Quarterly inspections required per NFPA 69 • Local Fire Protection Distributor to stock and supply spare parts as needed • Emergency reconditioning after system discharge – 24/7 • Minor system troubleshooting Fenwal Protection Systems Proprietary FENWAL Protection Systems Explosion Hazard Evaluation A thorough review of the plant, processes, equipment and materials CONSIDER: Normal, Abnormal and Upset Conditions Ignition Sources Geometry and Strength Housekeeping Process Temperature and Pressure Limits Existing Explosion Prevention and Protection Measures Material Hazards Fenwal Protection Systems Proprietary FENWAL Protection Systems Fenwal Protection Systems Proprietary 18