The Difference Between Fume Hood and Biosafety Cabinet

A fume hood and a biosafety cabinet (BSC) are specialized types of laboratory equipment. While both devices are similar in their primary purposes and design, there are differences in function, operation, and other factors. 

Level of Protection

Fume hood protects a user from inhaling toxic or volatile chemicals. It also serves as a physical barrier between the materials and the lab, which eliminates the risk of chemical spills, runaway reactions, and fires.

There are different types of hoods, which are designed for different kinds of protection:

  • General purpose, benchtop fume hood;
  • Perchloric acid fume hood – Includes built-in water wash down systems to prevent explosive perchlorate salt deposits;
  • Radioisotope fume hood – Protection from radioactive materials;
  • Acid digestion – Made of acid-resistant materials and is suitable for high service temperatures;
  • Floor mounted – Allows you to transfer equipment and materials into and out from the hood.

Slightly different from a fume hood, a biosafety cabinet protects users, products, and the environment. Here is a more detailed rundown of the protection specifics:

  • Class I cabinet is the most basic biosafety cabinet which works with biosafety levels 1, 2, and 3. It offers moderate product protection as unsterilized room air is drawn over the work surface.
  • Class II cabinet is also suitable for levels 1, 2, and 3. It provides enough protection to work with infectious agents and tissue culture.
  • Class III cabinet is used for working with very high-risk biological agents and characterized by biosafety level 4. All materials are decontaminated when entering or exiting this type of biosafety cabinet.

Operating Principle

A fume hood is usually designed to operate as a bypass hood, which ensures continuous airflow into the work surface with the sash closed. This way, a user is not exposed to toxins coming out of the air exhaust system.

There are different kinds of bypass hoods, such as auxiliary air, high-performance, and reduced air volume hoods. These vary in sash settings and hood-airflow conditions.

As the air enters a biosafety cabinet, the device uses HEPA- and/or Carbon-filtered laminar (unidirectional) airflow to remove contaminants. The air flow is combined with suction below the working surface to prevent unfiltered air from entering the space. 

Plus, the same kind of filter is used to remove airborne contaminants coming from inside of the biosafety cabinet. This way, operators and the environment are protected in addition to the product.

Materials

When used appropriately, a fume hood acts as an effective device for containment of the following agents:

  • Hazardous chemicals
  • Volatile liquids, dust, and mists
  • Radioactive materials
  • Odor and gases
  • Aerosols
  • Flammables

However, there are some limitations. For example, it’s ineffective for working with pressurized systems, micro-organisms, highly hazardous substances, and some other chemicals.

Depending on a particular class of cabinets, this equipment can be used for different materials. Examples of research materials that can be used in a biosafety cabinet include infectious microorganisms, viruses, bacteria, pathogens, contaminants, and other hazardous particulates. Overall, it allows for the safe handling of different kinds of materials but only according to the specifics of each biosafety cabinet class.

Possible Uses

A fume hood can act as a suitable containment device for various settings. Although they are not limited to examples below, here are the most common uses:

  • Laboratories
  • Educational facilities
  • Forensic laboratories

Biosafety cabinets are used in research, clinical, industrial, and pharmacy settings, such as: 

  • Life science research
  • Cell culture processing
  • Other applications where protection of the user, work product, the environment, and mitigation of cross-contamination on the work surface are needed.

For both a fume hood and a biosafety cabinet, there are requirements for safe use. Those rules should be followed in all the mentioned conditions. For example, it includes not placing chemicals or equipment inside that are not currently needed, blocking off the exhaust slots, preparing a plan of action for emergencies, such as a power failure, etc.