Legionella Testing / Biosafety Training


Richard W Gilpin PhD Blog

BSC Information in NSF 49-2016 - Not in BMBL

BMBL 5th Edition - Appendix A – Primary Containment for Biohazards information is at least 10-years out of date.
Current BSC information is published in the NSF International Standard/American National Standard NSF/ANSI 49 - 2016 Biosafety Cabinetry: Design, Construction, Performance, and Field Certification

Out-of-Date BMBL Information                                          2017 NSF Current Information

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

Most BSCs use HEPA filters                                                   Most BSCs use ULPA or HEPA 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 Uniform Downflow terms

Class II, Types A1, A2, B1, & B2                                              Class II, Types A1, A2, C1, B1, & B2

Type A1 BSC 75 lfm inflow                                                        Type A1 BSC has 100 lfm inflow - Type A1 BSCs are not manufactured

 A2 BSCs not to be used with volatiles                          Canopy-connected A2, & C1 BSCs can be used with volatile chemicals if permitted by                                                                                                                                                                                            risk analysis

Canopy hood for A1 & A2 BSCs                                          Canopy connection for A2 and C1 BSCs

Canopy gap usually 1 inch                                                       Canopy gap usually 2 inches or varies

NSF/ANSI Standard 49-2007                                             NSF/ANSI Standard 49-2016 - published in March 2017

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

Type B1 BSC preferably dedicated exhaust            Type B1 & B2 BSCs are required to have a dedicated exhaust

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)

Flammable chemicals should not be used             Flammable chemicals may be 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 removed on newer BSCs

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

Tables & Figures are outdated                                       Replace tables & figures from NSF 49-2016 edition