Up until the past couple years, standard MERV8 pre-filters, MERV14 cartridge style mid-filters, and HEPA final filters were the industry standard for indoor firing range ventilation systems.
Many high volume commercial ranges were changing their pre-filters every couple weeks, their cartridge mid-filters every other month, and their HEPA filters every 9-12 months. With the introduction of the high pressure stiff pocket ‘bag’ filter, filter expenses are dropping dramatically. Pocket filters take the place of both the traditional MERV8 pre-filters and MERV14 cartridge filters. Feedback from our owner base has shown that the pocket filters are lasting longer, cost less, and extend HEPA filter life longer than the traditional pre/mid setup.
Caution should be taken when ordering pocket filters and installing them. The pockets should stand vertically. A 20x24 pocket filter is not the same as a 24x20 pocket filter. It is always best to verify the sizes needed by physically measuring the height of the filter rack channels. When installing the filters, be careful not to damage or cut the bottom of the pockets on the filter track when sliding them across the rack.