Biosafety cabinets

When working with a pathogenic organism, laboratory staff should be protected from infections, and the environment from contamination. A biosafety cabinet  is therefore required for activities with open vessels and in case of aerosol production. Biosafety cabinets are classified into 3 classes. In the current page, the designation “biosafety cabinet” is used to mean a Class II cabinet, which is the most used type.

As they often look similar, it is important to be able to recognize the difference between a biosafety cabinet, a laminar flow and a fume hood:

The biosafety cabinet provides user protection against particles and aerosols, and it does not protect against the vapors of chemicals. When working with chemical products a chemical hood (fume hood) is needed. In a laminal flow cabinet, the air flow is horizontal, therefore it does not provide user protection, but it only provides sample protection.

The biosafety cabinet provides a physical barrier consisting of a vertical air flow (aerosol protection) and a glass window (spills and splashes protection). Biosafety cabinets are not completely sealed, therefore gloves, lab coat with long sleeves and protective glasses have to be worn for spills and splashes protection. Gloves have to cover the lab coat in order not to leave the skin of the arm unprotected.

The biosafety cabinet provides user protection only if it is used properly:

  • The forearms must be parallel and at the same level of the work surface
  • The face must be well behind the protective glass
  • Movements have to be carried slowly not to disturb the air flow
  • For the same reason the biosafety cabinet should not be located close to a door, other operators should walk slowly in its close proximity, and no big equipment or a Bunsen burner should be located inside
  • Moreover, the front and rear grids must be left free of items