A pocket filter is an air filter with pockets that is used with heating, ventilation and air conditioning (HVAC) filter appliances. Mostly used for reducing dust in the air, a pocket filter also can take in many other particle types, and must be able to reduce the particle count by at least 90 percent to be legally sold. There are two types of material used for pocket filters: glass fiber and synthetic fiber. An electrical charge applied to the filter materials helps it collect particles, and some are made to ward off bacterial growth.
Dust and particles are everywhere and, while they can never be fully eradicated, most people are not around enough particles for them to cause irritation or serious problems. In hospitals, the existence of particles can be a problem, because they can cause respiratory problems or make it difficult for some sensitive people to breath. Paint booths and inside areas where painters are working can trigger irritation as a result of the particles created by the paint. For any sensitive person and for business where particles are rampant, air filters are used to help people breath.
There are many types of air filters, and one of them is the pocket filter. This filter is not made to fit in a pocket; instead, it has several pockets added to the filter’s metal lining. The number of pockets varies by manufacturer and filter size, but there generally are from three to 12 pockets. U.S. Environmental Protection Agency (EPA) regulations require that pocket filters be able to reduce particles by 90 percent to 95 percent, but many high-quality filters reduce even more than this.
Two materials are used to make pocket filter pieces: glass fiber or synthetic fiber. Glass fiber was the first one used and, though synthetic fiber is thought of as an advancement, glass fiber lasts about four times longer than synthetic. It also has better efficiency over time, but it can be prone to growing and collecting bacteria. Synthetic material does not have the same efficiency over time or the same longevity as glass, but it is resistant to bacterial growth, which makes it ideal for hospitals and scientific establishments that cannot risk bacteria problems.
Most pocket filter units have an electric charge. This charge is applied to the material so it can attract dust and other particles with higher efficiency. The problem with charging synthetic material is that it will lose its efficiency quicker than if no charge were applied to the pocket filter.