HEPA Filter

The function of a biosafety cabinet is dependent upon the High Efficiency Particulate Air (HEPA) filter (See Figure to Right) within the plenum of the unit. The overall basis for HEPA filter function relies on the combination of multiple physical forces: inertial impaction (direct blocking of the particulates via the filter medium), diffusion (Brownian motion), Interception (“straining”) and electrostatic forces. Larger particulates are typically more efficiently blocked by interception and impaction; whereas smaller particles tend to be more efficiently retained by diffusion or electrostatic forces.