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)

Ducts and plenums:

Type I hood: must be made of nothing less than 0.055 inch steel or stainless steel and at least 0.04 inch thick.

Type II hood: must be made of rigid metallic materials complying with HVAC air distribution duct requirements.

Joints & Seams of Ducts:

Type I hood: must be made with a liquid-tight weld or braze made on the outside surface of the duct system.

Type II hood: Must be made airtight by using tapes, gasket or other.

Grease Duct:

Type I hood: a grease duct that penetrates a ceiling, wall or floor must be enclosed in a duct enclosure from the point of penetration to the outside.

Type II hood: no requirement.

Duct Velocity:

Type I hood: Must not be less than 1,500 feet per minute and no more than2,500 feet per minute.

Type II hood: no requirement.

Exhaust Fan Outlet:

Type I hood: The bottom exhaust fan outlet must be at least 2 feet above the roof and the upblast exhaust fan must have its outlets 2 feet above the roof.

Type II hood: in-line fans are allowed.

Exhaust Fan Termination:

Type I hood: Exhaust outlets must be at least 10 feet horizontally from the same building, adjacent to property line or air intake opening into any building and must be located at least 10 feet above the adjoining grade level.

Type II hood: no requirement.

Exhaust Fan:

Type I hood: Any type of fan that is UL listed for use in grease exhaust systems and is installed with the terms of its listing and the manufacturer’s instructions.

Type II hood: No requirements.

Hood Materials:

Type I hood: Stainless steel must not be less than 0.03 inch.

Type II hood: Stainless steel must not be less than 0.030 inch.

Ceilings:

Type I hood: Ceilings within 18 inches of the top of the hood must be constructed with materials conforming to 1-hour fire-resistive construction on the hood side. Hoods must also be less than 12 inches from the ceiling/wall and must be flashed solidly with materials required for hoods above or materials conforming to 1 -hour fire-resistive construction. Hoods recessed in the ceiling must be enclosed in a rated enclosure. Ceilings must also be constructed with materials conforming to 1-hour fire-resistive construction on the hood side to distance of 18 inches from the hood to ceiling.

Type II hood: no requirement.

Grease Filters or Extractors:

Type I hood: must be installed and designed for a specific purpose.

Type II hood: no requirement.

Fire-extinguishing:

Type I hood: system is generally required.

Type II hood: no requirement.

https://www.kcmn.us/docs/PublicHealth/Env_Hlth_Info/ventguide.pdf