Firing range air filtration presents two key challenges, centering on the protection of both people and equipment. In addition to removing hazardous contaminants generated by firearm discharge, air filtration systems must filter make-up air to protect HVAC equipment from outside contaminants.
In accordance with the American Society of Heating, Refrigeration and Air conditioning Engineers (ASHRAE) Standard 52.2, make-up air should be filtered with a Minimum Efficiency Reporting Value (MERV) 14 filter. These should also be sized to provide optimal efficiency, with adequate sealing mechanisms compatible with the individual HVAC system.
Re-circulated or exhaust air must be filtered at the point of removal, using a minimum 99.97% High Efficiency Particulate Air (HEPA) filter, per the Institute of Environmental Sciences and Technology (IEST) recommended particle for HEPA/ULPA filters (IEST RP-CC001). To provide an extended life cycle of the HEPA filters, it’s also recommended that HEPA filters be pre-filtered with a minimum of MERV 14 filters. Likewise, all filter sections should have pressure-measuring devices for filter maintenance.