As a secondary or final filter, HVAC pocket air filters are often used after (behind) a pleated filter. HVAC pocket air filters, also known as pocket filters and bag filters, are available in three degrees of efficiency: 65, 85, and 95%, or MERV 11, 13, and 15 ratings. It is often used as a medium&fine filter. HVAC pocket air filters are constructed with galvanized steel frames and sections of synthetic non-woven fabric media to create pockets. The bag's flexible stitching helps to maintain the media's shape in a variety of airflow circumstances. The stitching is sealed with thermoplastic resin to stop any leaks. There can be a specific number of bags in each bag-type air filter, such as a 3, 4, 5, 6 or 8 pocket bag filter. They can be modified to meet the requirements of the relevant applications. Applications HVAC pocket air filters are ideal in applications where the air systems work around the clock, like a larger office tower, school, hospital, factory, data centers, etc. In earlier applications without VAV fans, HVAC pocket air filters are also utilized.
