Up-Blast Stack Cap

The Up-Blast Stack Cap with a non-back draft damper is a vital component in industrial and commercial exhaust systems, designed to ensure proper ventilation and system integrity. Installed at the termination point of a vertical exhaust stack—such as those used in spray booths, welding stations, and general industrial ventilation—this cap facilitates the safe and efficient discharge of exhaust air into the atmosphere while preventing the entry of unwanted elements. Key Features: Non-Back Draft Damper: When the exhaust fan is running, the damper opens to allow free airflow. When the fan shuts off, the blades close automatically, preventing rain, snow, debris, or outside air from entering the duct system. This helps preserve indoor air quality and protects against moisture damage. Code Compliance: Many state and local codes require Up-Blast Stack Caps with backdraft dampers to ensure safety, minimize contamination risks, and maintain effective system performance. Vertical Discharge Recommendation: It is strongly recommended to terminate exhaust stacks at least 6 feet above the roofline to prevent re-entrainment of exhaust into HVAC intakes, open windows, makeup air units, and other rooftop openings. Standards Reference: For further guidance, refer to NFPA 33 (Section 5.11) and NFPA 91 for standards related to safe exhaust system design. More information is available at www.nfpa.org. Technical Requirements: A minimum air velocity of 2,500 FPM and 1/4″ static pressure loss is required to properly operate the damper blades. Product Options & Availability: Available in standard galvanized steel or stainless steel for enhanced corrosion resistance. Standard sizes include 6″, 8″, and more—custom sizes available upon request. Fabrication time: 4–10 working days. Collar is sized to slip over spiral pipe for easy installation. Also known as: Upblast, exhaust roof cap, exhaust cap, roof ventilation cap, exhaust rain cap, vent hood roof cap, exhaust rain flap, rain cap roof, up-blast, rain cap, upblast exhaust fan, roof vent pipe cover, exhaust pipe flapper, rain caps for vent pipes, pipe rain cap, upblast fan, upblast roof exhaust fan, stainless steel rain cap, exhaust rain cap, upblast ventilator, 6 exhaust rain cap, exhaust cover flap, Upflow Cap with Damper, Industrial-Duty Stack Cap, Sky Blasts, Wind band Stack Caps, or stack cap. Contact us for pricing, custom sizes, and lead time details. Also available in Stainless Steel.  Call for price and availability.