High-Efficiency Particulate Arrestance (HEPA) filters were originally developed to filter fine radioactive particles from the air. They filter with a minimum efficiency of 99.97% of particles at 0.3 microns and 95% of particles at 0.1 microns; one micron measures just 1/10,000 of a centimeter. To put this into perspective, the smallest particle visible to the naked eye is 40 microns. 0.3 microns is smaller than mold spores, pet allergens, dust mites and pollen alike. Medical applications such as operating rooms, clean rooms, pharmaceutical manufacturing facilities all employ HEPA filters, along with any environment where sterile conditions are required.
Medical grade HEPA filters feature a highly efficient filter paper that is folded in a concertina configuration. This maximizes the filter's surface area, which allows air to flow through it with minimal resistance. There is a particular ratio of airflow volume to filter paper which must be reflected in the configuration of the filter to achieve the 99.97% efficiency rating. If the unit is lacking enough filter paper, the efficiency rating will fail HEPA standards.
How are AussieAir HEPA filters made?
First, a steel filter casing encapsulates an airtight bonded filter paper. While HEPA filters cannot be cleaned or even vacuumed due to their delicate nature, they are designed to last three or more years with proper pre-filtration in place. The external face may also feature a gasket or other type of airtight seal to ensure no air is allowed to bypass the filter itself during operation.