BMBL - Table 3

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TABLE 3. COMPARISON OF BIOLOGICAL SAFETY CABINETS.

Type Face velocity (lfpm) Airflow Pattern Radionuclides/
Toxic Chemicals Biosafety Level (s) Product Protection

Class I*, open front 75 In at front; out rear and top through HEPA filter No 2,3 No

Class II: Type A 75 70% recirculated through HEPA; exhaust through HEPA No 2,3 Yes

Type B1 100 30% recirculated through HEPA; exhaust via HEPA and hardducted Yes (Low Levels/volatility) 2,3 Yes

Type B2 100 No recirculation; total exhaust via HEPA and hardducted Yes 2,3 Yes

Type B3 100 Same as IIA, but plena under negative pressure to room and exhaust air is ducted Yes 2,3 Yes

Class III NA Supply air inlets and exhaust through 2 HEPA filters Yes 3,4 Yes

*glove panels may be added and will increase face velocity to 150 lfpm; gloves may be added with an inlet air pressure release that will allow work with chemicals/radionuclides

Office of Health and Safety, Centers for Disease Control and Prevention,
1600 Clifton Road N.E., Mail Stop F05 Atlanta, Georgia 30333, USA
Last Modified: 1/2/97

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Type	Face velocity (lfpm)	Airflow Pattern	Radionuclides/ Toxic Chemicals	Biosafety Level (s)	Product Protection
Class I*, open front	75	In at front; out rear and top through HEPA filter	No	2,3	No
Class II: Type A	75	70% recirculated through HEPA; exhaust through HEPA	No	2,3	Yes
Type B1	100	30% recirculated through HEPA; exhaust via HEPA and hardducted	Yes (Low Levels/volatility)	2,3	Yes
Type B2	100	No recirculation; total exhaust via HEPA and hardducted	Yes	2,3	Yes
Type B3	100	Same as IIA, but plena under negative pressure to room and exhaust air is ducted	Yes	2,3	Yes
Class III	NA	Supply air inlets and exhaust through 2 HEPA filters	Yes	3,4	Yes

Office of Health and Safety, Centers for Disease Control and Prevention, 1600 Clifton Road N.E., Mail Stop F05 Atlanta, Georgia 30333, USA Last Modified: 1/2/97
Send us your Comments.