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    Restaurant Duct Requirements: Grease-Tight Access Panels

    By Mark Conroy

    Restaurant exhaust ducts are provided from the hoods over the cooking appliances and lead to the outside of the building. They are intended to remove odors and grease-laden vapors directly to the outdoors and are never interconnected with the building ventilation system. However, the main purpose of the exhaust ductwork is to reduce the potential fire hazard resulting from the cooking operations. The seams and joints of exhaust ductwork are required to have a liquid-tight, continuous weld to prevent the cooking grease from migrating from the ductwork and extending the fire hazard to the area above the suspended ceiling and other concealed spaces.

    Exhaust ducts must have openings for inspection, servicing of fire protection systems, and for cleaning of the ductwork. The openings are typically on the sides and top of the duct, whereas the installation location is based upon accessibility. These openings are required to have special access panels. NFPA 96, Standard for Ventilation Control and Fire Protection of Commercial Cooking Operations requires access panels to comply with the following criteria:

    • Constructed of the same material as the duct
    • Be at least the same thickness as the duct
    • Have a gasket that is rated for at least 1500ºF
    • Be grease-tight
    • Have integral fasteners that are constructed of steel

    Since access panels are frequently removed for inspection and cleaning of the ductwork or servicing of the fire protection system, the panels can become warped or otherwise damaged. Also the panel gasket can be damaged, torn, or worn due to the constant removal and reinsertion of the panel. The following access panels intended for restaurant applications are rated to 2300ºF and comply with NFPA 96.

    Access Panels

    Rectangular Duct

    P/N Door Size
    D106F2GAL 11 x 7
    D128F2GA 13 x 9
    D1814F2GA 19 x 15
    D1612F2GA 16 x 12

    Rectangular Duct UL 1978

    P/N Door Size
    D106ULBI 10 x 6
    D1010ULBI 10 x 10
    D128ULBI 12 x 8
    D1814ULBI 18 x14

    Round Duct* UL 1978

    P/N Door Size
    DR10612ULBI 12 x 8
    DR12812ULBI 14 x 10

    (*Fit 12 inch diameter ducts)

    All door size dimensions are in inches

    Duct access panels that are leaking grease around the perimeter are not “grease-tight” and are not in compliance with NFPA 96. To bring the opening and access panel into compliance, the access door typically needs to be replaced. The replacement of non-compliant access panels with NFPA 96 compliant access panels will make the restaurant exhaust system safer and will increase your bottom line.

    Mark Conroy is an engineer in our Boston, MA office and a member of the NFPA 96 Technical Committee on Portable Fire Extinguishers.Copyright © 2016, all rights reserved.

    Disclaimer: The opinions expressed in the above Tech Series article are the author’s only and provide limited information. Although the information is believed to be reliable, Brooks Equipment ® Company, LLC expressly disclaims any warranty with respect to the information and any liability for errors or omissions. The user of this article or the product(s) is responsible for verifying the information’s accuracy from all available sources, including the product manufacturer. The authority having jurisdiction should be contacted for code interpretations.

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