Providing a source of outside air compliant with NFPA regulations and recommendations
As a recommended and often required addition to a purge and pressurization unit (PPU) or InPac unit, the stack package provide an easy means of providing fresh air to areas needing a source of non-hazardous air. Two basic designs are available. The standard stack package, comprised of spiral wound galvanized steel, is designed to tolerate wind gusts and steady winds up to 90 MPH, and our high wind design is capable of withstanding winds up to 120 MPH.
NFPA 496 (7.2) dictates that “protective gas” shall be air that is free of contaminants and contains only trace amounts of hazardous gas or vapor. It is further agreed that fresh air can be pulled as a protective air from a height of 25' above ground level because the prevalent hazardous gases are heavier than air, and therefore sink.
Because roof top units are already several feet above the ground, they require the shortest stacks.
At Specific Systems®, we manufacture HVAC specifically designed for the modular building industry. Our industrial systems can be used on any of the building/enclosure types below, and fit just as well on static structures as they do on modular buildings.