The Up-Blast Stack Cap with a non-back draft damper is a critical component used in exhaust systems to ensure proper ventilation and safety. The Stack Cap is installed at the end of a vertical exhaust stack, which could be part of a spray booth, welding booth, industrial ventilation, or other applications. Its main purpose is to facilitate the safe discharge of exhaust air into the atmosphere while preventing unwanted elements from entering the duct system.
The Up-Blast Stack Cap is equipped with a non-back draft damper. This damper is designed to allow air and fumes to exit the duct freely when the exhaust fan is operating. However, when the fan is turned off, the damper blades automatically close to prevent the entry of rain, snow, or outside air into the duct system. This is crucial for maintaining indoor air quality and preventing moisture-related damage.
Many state and local municipalities have regulations that mandate the use of Up-Blast Stack Caps with non-back draft dampers for exhaust systems. These regulations are in place to ensure safety, prevent contamination, and maintain the integrity of ventilation systems. Additionally, it is recommended to terminate the exhaust duct at least 6 feet above the roofline in a vertical fashion to prevent contaminants from being drawn into heating or air conditioning units, open windows, make-up air units, and other open vents on the roof.
The information provided suggests referring to NFPA (National Fire Protection Association) Standard 33, particularly Section 5.11, and NFPA Standard 91 for additional guidance and specific requirements related to exhaust systems and safety. These standards can be obtained from the NFPA website (www.nfpa.org).
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** To operate damper blades a minimum of 2,500 fpm of air velocity is required plus a 1/4″ of static pressure loss. **
Allow 4 to 10 working days for fabrication. Other sizes also available. Also available in Stainless Steel. Contact us for price and availability. Collar sized to slip OVER spiral pipe.