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BMBL 5th Edition - Appendix A – Primary Containment for Biohazards information is at least 10-years out of date..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 - 2018 - Published January 15, 2019.

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Out-of-Date BMBL Information.                               2018 NSF Current Information.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.                                                                    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 49-2018 published in January 2019. 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.