Legionella Testing / Biosafety Training


Dr Richard W Gilpin’s Blog

BSC Information in NSF 49-2018 Annex E — Not in BMBL

BMBL 5th Edition - Appendix A – Primary Containment for Biohazards information is at least 10-years out of date.
Current BSC design, construction, performance, and field certification is published in the NSF International Standard/American National Standard NSF/ANSI 49 - 2016

NSF 49 - 2018 Annex E Biosafety cabinet selection, installation, use, lifespan, and decommissioning Is the user manual distributed for informative / educational purposes – this document is not for sale. This document is the United States normative reference for biosafety cabinet (BSC) practices.

Out-of-Date BMBL Information                                          2018 NSF Current Information

Biological Safety Cabinets                                                       Biosafety Cabinets (name changed many years ago)

Most BSCs use HEPA filters                                                   Most BSCs use HEPA filters but some use ULPA filters

HEPA filters remove 99.97% of 0.3 um particles     HEPA filters 99.99%; ULPA filters 99.999% of 0.3 um particles 

Filter corrugated aluminum separators                         Corrugated aluminum separators rarely used

Laminar Flow                                                                                      Replaced with Zoned Downflow or Non-uniform Downflow terms

Class II, Types A1, A2, B1, & B2                                              Class II, Types A1, A2, C1, B1, & B2 (Type A1 BSCs no longer manufactured but still listed)

Canopy-connected BSCs                                                       Type A1, A2 and C1 (modified A2) BSCs are either canopy-connected or recirculate into lab

                                                                                                                       Type C1 BSCs are not direct connected to building exhaust (they are not modified B1 or B2 BSCs)

 A2 BSCs not to be used with volatiles                          Canopy-connected A2 and C1 BSCs are used with volatile chemicals if permitted by risk analysis

Canopy hood for A1 & A2 BSCs                                          Canopy connection for A2 and C1 BSCs (Thimble-connection or hood term no longer used)

Canopy gap usually 1 inch                                                       Canopy gap usually greater than one inche or varies

NSF/ANSI Standard 49-2007                                             NSF/ANSI Standard 49-2016 - published in March 2017. NSF 49 - 2018 Annex E published in November 2018

Type A BSC 70% downflow                                                  Type A BSC downflow varies > 50% to 80%

Type B1 BSC preferably dedicated exhaust            Type B1 & B2 BSCs are required to  each have their own individual dedicated exhaust ducting and fan

B2 BSC exhausts 1200 CFM room air                         B2 BSC exhausts room air at rate of 175 CFM/foot (16.3 m3/m) of BSC width

Horizontal Laminar Flow “Clean Bench”                   Unidirectional Flow Clean-Air Device (IEST RP CC002) is the correct term

Flammable chemicals should not be used             Flammable chemicals used in Class II, Type A2 or C1 BSCs or Type B1 or B2 BSCs if risk analysis permits
in Class II, Type A1 or A2 BSCs 

National Sanitation Foundation                                      NSF International (name changed decades ago)

BSCs are designed for 24-hour operation             BSC blower should be turned off and sash closed when operations are completed

70% ethanol (EtOH) wiping                                               70% ethanol not recommended as a disinfectant and may contain spores

1:100 dilution of bleach disinfection                             Bleach corrodes stainless steel - alternative disinfectant recommended

Correct sash position (8” or 10”)                                   Correct sash position (8”, 10” or 12”) - depends on BSC model

Touch-plate micro burners                                               Electric furnaces - flames not recommended

BSC drain pan valve                                                               Drain valve to be removed on newer BSCs when revised standard is published

Adequate clearance behind & on each side        6” minimum clearance behind & on each side of BSC

Tables & Figures are outdated                                       Replace all tables & figures from NSF 49-2018 Annex E