A HEPA filter consists of a thin sheet of boron silicate microfibers which is pleated. Corrugated aluminum separators are placed between the pleats to direct the air through the filter. A HEPA filter removes airborne particles and microorganisms.
Gases pass through it freely.
A HEPA filter typically lasts three to five years, depending on hours of operation, cleanliness of the laboratory, and type of work being performed. The annual certification of biological safety cabinets and laminar flow clean benches tests for the function status of the HEPA filters among other things.