18-28-507.11.2 Mounting position.

   Filters shall be installed at an angle of not less than 45 degrees (0.79 rad) from the horizontal and shall be equipped with a drip tray beneath the lower edge of the filters.

18-28-507.12 Canopy size and location.

   The inside lower edge of canopy-type commercial cooking hoods shall overhang or extend a horizontal distance of not less than 6 inches (152 mm) beyond the edge of the cooking surface, on all open sides. The vertical distance between the front lower lip of the hood and the cooking surface shall not exceed 4 feet (1219 mm).

   Exception: The hood shall be permitted to be flush with the outer edge of the cooking surface where the hood is closed to the appliance side by a noncombustible wall or panel.

18-28-507.13 Capacity of hoods.

   Canopy-type commercial cooking hoods shall exhaust a minimum quantity of air (Q) determined in accordance with this section and Sections 18-28-507.13.1 through 18-28-507.13.4.

where:

   A = The horizontal surface area of the hood, in square feet (m2).

   D = Distance in feet (m) between the lower lip of the hood and the cooking surface.

   P = That part of the perimeter of the hood that is open, in feet (m).

   Q = Quantity of air, in cubic feet per minute (m3/s).

18-28-507.13.1 Solid fuel-burning cooking appliances.

   The minimum airflow for Type I hoods used for solid fuel-burning cooking appliances, grease-burning charbroilers and similar appliances shall be:

 

Number of exposed sides	Formula
		For SI:
4 (island or central hood)	Q = 300A	Q = 1.52A
3 or less	Q = 200A	Q = 1.02A
Alternate formula	Q = 100PD	Q = 0.51PD

 

18-28-507.13.2 High temperature.

   The minimum airflow for Type I hoods used for high-temperature appliances such as deep-fat fryers shall be determined as follows:

 

Number of exposed sides	Formula
		For SI:
4 (island or central hood)	Q = 150A	Q = 0.76A
3 or less	Q = 100A	Q = 0.51A
Alternate formula	Q = 100PD	Q = 0.51PD

 

18-28-507.13.3 Medium temperature.

   The minimum airflow for Type I hoods used for medium-temperature appliances such as rotisseries, grills and ranges shall be determined as follows:

 

Number of exposed sides	Formula
		For SI:
4 (island or central hood)	Q = 100A	Q = 0.51A
3 or less	Q = 75A	Q = 0.38A
Alternate formula	Q = 50PD	Q = 0.25PD

 

18-28-507.13.4 Low temperature.

   The minimum airflow for Type I hoods used for low-temperature appliances such as medium-to-low temperature ranges, roasters, roasting ovens, pastry ovens and appliances approved for use under a Type II hood, such as pizza ovens, shall be determined as follows:

 

Number of exposed sides	Formula
		For SI:
4 (island or central hood)	Q = 75A	Q = 0.38A
3 or less	Q = 50A	Q = 0.25A
Alternate formula	Q = 50PD	Q = 0.25PD