The ventilation system has been designed to meet recommendations from the National Institute for Occupational Safety and Health (NIOSH) for indoor ranges. This includes both keeping the range under negative pressure and pulling fresh air downrange at a certain velocity. Air originates from behind the shooter and is pulled downrange at a certain speed. Before being exhausted to the outside, the range air passes through three stages of filtration: Stage 1: MERV 8, Stage 2: 95% HEPA, and Stage 3: 99.97% HEPA. This means that the air leaving the range is cleaner than the air entering! In addition to its safety benefits, the ventilation system keeps customers warm in the winter and cool in the summer.