Some people are using the term “Hood” to cover Fume Hoods and Biosafety Cabinets. To ensure that you choose the proper hood for your application, let’s examine their differences as they’re used for different purposes. Each of them also has 2 major sub-category: A2 and B2 for Biosafety Cabinets, and Ductless and Ducted for Fume Hoods. Below are the technical differences between the four types:

Equipment Type

Class II Type A2 Biological Safety Cabinet (BSC)

Class II Type B2 Biological Safety Cabinet (BSC)

Ductless Fume Hood

Ducted Fume Hood

Application

For handling pathogens. When optionally ducted: small amount of naturally evaporating non-corrosive, volatile organic chemicals.

For handling pathogens. Has builtin ducting to handle medium amount of heated, noncorrosive, volatile organic chemicals.

For handling medium amount of naturally evaporating, mildly corrosive, limited range of chemicals matching the carbon filter, no pathogens.

For handling large amount of heated, corrosive, and wide range of chemicals but not pathogens.

Protection Offered

Operation protection against biohazards inside. Product protection against outside contaminants.

Operator protection against biohazards and chemicals inside. Product protection against outside contaminants.

Operator protection against chemicals inside, but not pathogens, and no product protection against contaminants.

Airflow

About 2/3 of air from the plenum is recirculated as downflow, and 1/3 is exhausted into the lab through exhaust HEPA filter.

100% exhausted outside the building through exhaust HEPA filter, with no recirculation back into the work zone.

100% exhausted into the lab through exhaust Carbon filter.

100% exhausted outside the building without any filter, hence risk assessment of what is being dumped into the outside environment is suggested.

Requirements

Not applicable  |  Ducting, rooftop exhaust blower  |  Not applicable  |  Ducting, rooftop exhaust blower

Filtration

Exhaust and downflow HEPA filters  |  Exhaust Carbon filters  |  No filters at all

Restrictions

Even when ducted, this is not for forcibly evaporated chemicals due to recirculation back to the work zone, no corrosive chemicals.

No corrosive chemicals.

Not for handling pathogens and sterile samples. Not for handling forcibly evaporated or highly corrosive chemicals.

Not for handling pathogens and sterile samples.

Pictured Below

Esco Labculture® Class II Type A2 Biosafety Cabinet | Esco Labculture® Class II Type B2 Biosafety Cabinet

Esco Ascent™ Max Ductless Fumehood | Esco Frontier® Acela Ducted Fumehood