Wisconsin Kitchen Exhaust (Range Hood) Fire Codes
Every restaurant owner should know fire code guidelines for their commercial kitchen, especially when it comes to their exhaust system (range hoods). If these are not properly cleaned and inspected on a regular basis, this can result in a serious fire, damaging your entire kitchen and restaurant. If you do not know your state’s commercial kitchen fire codes, just read below (click on the link at the end of the summary to read about it in more detail).
Air removed by a mechanical exhaust system must be discharged outdoors.
Type I exhaust outlets on roof to be a minimum 40” above roof, 10 ft horizontally from buildings, property lines & air intakes. If air discharge is away from such locations, then only 5 ft is required. The minimum distance between vertical discharge fans and parapet type building structures must be 2 ft provided that such structures are not higher than the top of the fan discharge openings and exhaust discharge to be 10 ft above adjoining grade level. Outlets must be located no less than 10 ft horizontally from part of the same or contiguous building.
Type II exhaust outlets on roof to be minimum 30” above the roof or from exterior vertical walls, 10 ft horizontally from buildings, property lines, and 3 ft in all directions from openings into the building. Outlets must not be not less than 10 ft above adjoining grade level. Outlets must not be directed onto walkways. Outlets must meet the provision for exterior wall openings protectives per IBC.
Room or space served by hood must be under neutral or negative pressure.
Ventilation System Ducts and Exhaust Equipment:
Type I & II exhaust ducts must be independent of all other exhaust systems except as allowed.
Type I duct fan motor must be properly connected.
Type I duct must be 16 ga. (0.055”) steel or stainless steel 18 ga. (0.044”).
Type I duct joints, seams & penetrations must be liquid tight, with acceptable means providing a liquid tight seal.
Type I duct systems for Type I hoods has a duct velocity of > 500 ft/min unless exception met.
Separate Type I duct systems required unless exception met.
Type I duct system must be greater than 18” from combustible materials.
Type I duct must have ¼” per 12” slope if greater than 75’; 1 per 12 if greater than 75’ toward the hood or approved grease reservoir.
Type I duct clean outs to have door operable without tools.
Type I duct clean outs located a minimum of every 20 ft horizontally is indicated and size of clean out provides adequate edge distances to be maintained.
Personnel entry into Type I duct clean outs to have minimum openings of 22” x 20”.
Type I duct clean out must be provided on inlet & outlet side of inline fan used for kitchen hood. Clean outs to be within 3 ft of fan duct connections.
Duct enclosure required around Type I ducts enclosure can be built from building materials, or a listed grease wrap. Grease wraps may NOT be used if the duct is sealed using liquid tight seal.
Type I ducts to have clean out openings with approved sign to be placed on access openings, “ACCESS PANEL. DO NOT OBSTRUCT.”
Commercial Kitchen Hood:
Minimum hood metal thickness 0.046” for steel, 0.033” for stainless steel for Type I, Minimum hood metal thickness 0.029” for steel, 0.022” for stainless steel, or other approved material for Type II.
Type I hood must be greater than 18” from combustible materials unless exception is met.
Hood must overhang greater than 6” beyond the edge of the cooking surface, on all open sides. Minimum height from lower lip of hood and cooking surface is 4 ft unless exception met.
Fire suppression system must be installed for Type I.
Wisconsin General Fire Codes
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