by Rob Chopowick General Manager, Con

 by Rob Chopowick General Manager, Con-­‐Test ASHRAE & G.W. Knutson and K.J. Caplan, University of Minnesota RP-­‐70 The Effect of Room Air Challenge on the Efficiency of Laboratory Fume Hoods 1. Smoke test 2. Face velocity 3. Tracer gas Method of tesOng only “The purpose…to provide…Industry Standard Prac7ces” (2010 version, sec7on 1.0) “SEFA encourages the use of third party independent tes7ng where appropriate” (2010 version, Disclaimer) This prac:ce is designed to be consistent with the ASHRAE 110 protocol (sec:on 3.2) Refer to ASHRAE 110-­‐1995 (or latest edi:on) for velocity measurement procedures (sec:on 4.4.1, 5.3.4) The ASHRAE 110 is the recognized method for evalua:ng the performance of fume hoods. (sec:on 5.3) SEFA recommends the ASHRAE 110-­‐1995 (or most current edi:on) test (sec:on 5.3.5 -­‐Containment tes:ng -­‐ As Installed) “…it remains the responsibility of the users of the Standard to judge the suitability for their par7cular purpose” (Preface, note 2) Tracer gas test MAY be performed Tracer gas SHALL be performed The test specified in ASHRAE 110 shall be performed. (Sec:on5.3 -­‐ Manufacturer's test -­‐ Containment test) Face velocity shall be determined in accordance with the containment test specified in Clause 5.3 (see above) (SecOon 9.4.1 -­‐ Face velocity test) The test specified in ASHRAE 110 shall be performed (Sec:on 9.4.2 -­‐ Field Test -­‐ Containment Test) “The primary purpose of this standard is to establish minimum requirements and best prac7ces for laboratory ven7la7on systems…” (2012 version, sec7on 1.2) Test specifica:ons used for selec:ng a hood, in commissioning or in rou:ne tes:ng, shall refer to the applicable ANSI/ASHRAE 110 defined performance tests or to a test standard recognized to be equivalent. (sec:on 6.1.1) Airflow visualiza:on tests shall be conducted as described in the ANSI/
ASHRAE 110-­‐1995 Method of Tes:ng Performance of Laboratory Fume Hoods. (sec:on 6.1.2.1) The average face velocity shall be determined by the method described in the current version of ANSI/ASHRAE 110 Method of Tes:ng Performance of Laboratory Fume Hoods. (sec:on 6.1.2.5) The tracer gas containment tests shall be conducted as described in the ANSI/ASHRAE 110-­‐1995 Method of Tes:ng Performance of Laboratory Fume Hoods. (sec:on 6.1.2.7) < 60 fpm 60 -­‐ 80 fpm 80 -­‐ 100 fpm 100–120 fpm 120–150 fpm < 0.30 m/s 0.30 -­‐ 0.40 m/s -­‐ not recommended -­‐environmental and user dynamics have much greater impact -­‐tracer gas tesOng should be used to verify containment -­‐ environment should be relaOvely ideal -­‐ requires prudent user pracOces -­‐ hood must have excellent containment characterisOcs > 150 fpm 0.40 -­‐ 0.50 m/s 0.50 -­‐ 0.60 m/s 0.60 -­‐ 0.75 m/s > 0.75 m/s -­‐ most recommended range -­‐ containment usually effecOve -­‐ reasonable cost effecOveness -­‐ similar containment characterisOcs as 80 to 100 fpm range but at higher operaOng costs -­‐ may be a opOon if containment at 80 to 100 fpm is inadequate -­‐ containment characterisOcs may be comparable to lower ranges -­‐ operaOng costs very much higher -­‐ generally agreed that there may be turbulent flow which increases potenOal for leakage “While ASHRAE 110 has defined basic fume hood test procedures, a performance guideline was not available. A primary feature of MD15128 is the iden7fica7on of specific pass/fail performance criteria” (2004 version, pg 3-­‐4) While American Society of Hea:ng, Refrigera:ng and Air-­‐
Condi:oning Engineers ASHRAE 110-­‐1995: Method of Tes:ng Performance of Laboratory Fume Hoods has defined the basic fume hood test procedures, a guideline that defines fume hood performance in not currently available. MD 15128 has been developed to fulfill this need.(Preface, pg.3) Use equipment and procedures as described in ANSI/ASHRAE 110-­‐1995, with the following excep:ons... (Sec:on 6.9.4 -­‐ Tracer Gas Procedures) The devices and apparatus described below were designed to facilitate implementa:on of this guideline and the ANSI/ASHRAE 110 standard's smoke visualiza:on test, and to provide a consistent test protocol (Appendix A.2) CANADA Organiza-on CSA Z316.5 MD 15128 OHS Regs. Fire Codes Canadian Standards AssociaOon Public Works and Government Services Canada (PWGSC) Federal and Provincial OHS Agencies MD 15129 (Perchloric acid) Public Works and Government Services Canada (PWGSC) Canadian Commission of Building and Fire Codes (CCBFC) GD-­‐52 (Radioisotope hoods) Canadian Nuclear Safety Commission UNITED STATES American Society of HeaOng, RefrigeraOon and Air CondiOoning Engineers AIHA Z9.5 American Industrial Hygiene AssociaOon NEBB Procedural Standard NaOonal Environmental Balancing AssociaOon NIH SpecificaOons U.S. NaOonal InsOtutes of Health SEFA 1 ScienOfic Equipment and Furniture AssociaOon Industrial VenOlaOon Book American Conference of Governmental Industrial Hygienists Prudent PracOces in the Lab NaOonal Research Council ASHRAE 110 OSHA RegulaOons OccupaOonal Safety and Health AdministraOon NFPA NaOonal Fire ProtecOon AssociaOon What makes it different? Bind-­‐
ing* Process Authority Recognized As LegislaOon Government Law Codified Rules  Consensus Recognized Body Necessary "Shall", "Will", "Must * Guidelines Consensus Recognized Body Desirable "Should", "Would", "May"  Recommended Prac-ces Consensus Recognized Body EffecOve Benchmarks  Regula-ons Standard * Standards can be adopted by authorita:ve bodies and become enforceable ** Standards may have specified discre:onary elements Modi-­‐
fiable ** CANADA Document Type Jurisdic-on CSA Z316.5 Standard None MD 15128 Guideline Laboratories managed by PWGSC OHS Regs. Law Provincial (and Federal) Fire Codes Standard Provincial MD 15129 (Perchloric acid) Guideline Laboratories managed by PWGSC GD-­‐52 (Radioisotope hoods) Guideline Nuclear Laboratories ASHRAE 110 Standard None AIHA Z9.5 Standard None NEBB Procedural Standard NIH SEFA 1 Industrial VenOlaOon Book Prudent PracOces in the Lab Standard Guideline Recommended Pract. Recommended Pract. Recommended Pract. None NIH buildings and faciliOes None None None OSHA Regs. and NFPA Law State (and Federal) UNITED STATES Predominantly all fume hood reference documents are either: 1.  non-­‐binding or at least modifiable 2. limited in their jurisdicOon CANADA Document Type Jurisdic-on CSA Z316.5 Standard None MD 15128 Guideline Laboratories managed by PWGSC ASHRAE 110 Standard None AIHA Z9.5 Guideline None SEFA 1 Recommended PracOce None UNITED STATES Assurance about safety ProtecOon from harmful gases, vapours and aerosols generated within the fume hood. Nothing is absolute Many factors involved Proximity of supply air diffusers Proximity of doors (and windows) LocaOon of hood in room rela:ve to other lab equipment and furniture Inadequate exhaust draw Incorrect system configura:on Baffles, bypasses, air foils or sashes improperly set or misaligned Makeshio user modificaOons Poor workmanship Interfering with air flows Overloading hood with equipment, improperly placing apparatus and containers, covering air foil CreaOng excessive thermal challenges within the hood Improper use Using it for purposes that would be beber served by other equipment such as biosafety cabinets and glove boxes Limited breadth Lacks performance criteria $$$$    ASHRAE 110    AIHA Z9.5 110  110 SEFA 1 110 110 110 Noise BC OHS Part 30 Hood sta-c pressure 110 Exhaust System  Airflow monitor/alarm         Cross DraR MD 15128 Installa-on 110 Exhaust Flow Tracer Gas 110 VAV Func-on Inflow Velocity  Bypass Effec-veness Airflow Visualiza-on CSA 316.5       110           Test name Acceptance Criteria 1. Airflow visualizaOon No visible escape of smoke 2. Inflow face velocity VARIOUS 3. Tracer gas <0.10 ppm (<0.05 ppm MD15128) 4. Bypass effecOveness < 3x avg. velocity at design height (<250 fpm (1.25 m/s) MD15128) 5. VAV funcOon Response Ome < 3 sec., Time to steady state < 5 sec. 6. Minimum exhaust flow 150-­‐375 hood ACH (NFPA > 25 cfm/sq.o. work surface) 7. InstallaOon Sash, baffles, exhaust duct, lights, power, noise ok 8. Cross drao < 30 fpm or < 50% of avg. face velocity (<30 fpm MD15128) 9. Airflow monitor/alarm Installed properly, accurate within 10%, <3 sec delay 10. Exhaust System Exhaust stack >10 o, exhaust vel. prevents re-­‐entrainment 11. Hood StaOc Pressure 0.1 -­‐0.75 in.w.g. (<.25 MD15128) 12. Noise Approx. 50 dBA (<70 dBA MD15128) *Criteria may vary from document to document but selected criteria above are commonly referenced. SpecificaOon agreement Pass/Fail protocol agreement 1. All manufacturers test the fume hoods so that is enough 2. TesOng a fume hood means that it is cerOfied 3. Once it is tested it is safe to use 4. TesOng only takes a few minutes 5. TesOng is not expensive The manufacturer can create a very effec7ve safety device but its effec7veness is significantly dependant on how well it is integrated into the lab environment. To authorita7vely or officially a[est or confirm someone or something as being genuine or true as represented, or as complying or mee7ng specified requirements or standards. False sense of security Adhesive sOcker Too many variables Historical methods took only a few minutes Dependent of total number of tests Test descrip-on Es-mated -me to complete tests (varies with hood sizes and sash configura-ons) Set-­‐up and take down 5-­‐15 min (+ 15 min for tracer gas set-­‐up) 1. Airflow visualizaOon 6 locaOons x 2 challenges x 10-­‐15 secs/observ = 2-­‐3 min 2. Inflow face velocity 2 sash heights x 8-­‐12 locaOons x 30 sec rdgs = 8-­‐12 min SUB-­‐TOTAL (approx.) 20-­‐25 min (limited set-­‐up and take down) 3. Tracer gas 3 staOc tests + 1 dynamic + 1 perimeter scan = 25-­‐35 min 4. Bypass effecOveness 5-­‐8 min 5. VAV funcOon 5-­‐8 min 6. Exhaust flow 5-­‐8 min (if accessible – longer of difficult to access) 7. InstallaOon 3-­‐5 min 8. Cross drao 6 locaOons x 30 sec readings = 5-­‐6 min SUB-­‐TOTAL (approx.) No tracer gas = ¾ -­‐ 1¼ hrs / With tracer gas: 1½ – 2 hrs Airflow monitor/alarm 3-­‐8 min 9. 10. Exhaust System 15-­‐30 min (coordinaOng roooop access and ease of access 11. Hood StaOc Pressure 10-­‐15 min 12. Noise 3-­‐5 min TOTAL (approx.) 1¼ – 2 ¼ hrs / With tracer gas: 1¾ – 3 hrs