SECTION 748:20-13-9. IMC® 2015 Chapter 5 Exhaust Systems

  Chapter 5 of the IMC® 2015 has been adopted with the following modifications:

(1)   Section [F] 502.15 Repair garages. This section has been modified to require compliance with Section 2311.4.3 of the International Fire Code® when designing basement or pit ventilation. This section has been modified to read: [F] 502.15 Repair garages. Where Class I liquids or LP-gas are stored or used within a building having a basement or pit wherein flammable vapors could accumulate, the basement or pit shall be provided with ventilation designed in accordance with Section 2311.4.3 of the International Fire Code® to prevent the accumulation of flammable vapors therein.

(2)   Section [F] 502.16.1 Design. This section has been modified to clarify exhaust outlets should be located within 18 inches (475 mm) of the high point of the room on exterior walls or the roof and to change the ventilation rate from not less than 1 cubic foot per minute per 12 cubic feet of room volume to 1 cubic foot per square foot of room area. This section has been modified to read: [F] 502.16.1 Design.

(A)   Indoor locations shall be ventilated utilizing air supply inlets and exhaust outlets arranged to provide uniform air movement to the extent practical. Inlets shall be uniformly arranged on exterior walls near floor level. Outlets shall be located within 18 inches (457 mm) of the high point of the room in exterior walls or the roof.

(B)   Ventilation shall be by a continuous mechanical ventilation system or by a mechanical ventilation system activated by a continuously monitoring natural gas detection system, or for hydrogen, a continuously monitoring flammable gas detection system, each activating at a gas concentration of not more than 25 percent of the lower flammable limit (LFL). In all cases, the system shall shut down the fueling system in the event of failure of the ventilation system.

(C)   The ventilation rate shall not be less than 1 cubic foot per minute per square foot [0.0051 cubic meters per (second square meter)] of room area.

(3)   Section 506.3.1.1 Grease duct materials. This section has been added to clarify the language between the code and NFPA® 96 regarding the type of steel to be utilized. This section has been modified to read: 506.3.1.1 Grease duct materials. Grease ducts serving Type I hoods shall be constructed of non-galvanized carbon steel having a minimum thickness of 0.0575 inch (1.463 mm) (No. 16 gage) or stainless steel not less than 0.0450 inch (1.14 mm) (No. 18 gage) in thickness. Exception: Factory-built commercial kitchen grease ducts listed and labeled in accordance with UL 1978 and installed in accordance with Section 304.1.

(4)   Section 507.2. Type I hoods. This section has been modified to add an additional exception for installation of Type II hoods when specific conditions are met. This section has been modified to read: 507.2 Type I hoods. Type I hoods shall be installed where cooking appliances produce grease or smoke as a result of the cooking process. Type I hoods shall be installed over medium-duty, heavy-duty, and extra- heavy-duty cooking appliances. Exceptions:

(A)   A Type I hood shall not be required for an electric cooking appliance where an approved testing agency provides documentation that the appliance effluent contains 5 mg per cubic meter when tested at an exhaust flow rate of 500 cfm (0.236 cubic meters per second) in accordance with UL 710B.

(B)   In non-commercial cooking occupancies a residential or Type II hood can be installed over a medium-duty residential appliance when approved.

[Source: Added at 29 Ok Reg 1659, eff 11-1-12; Amended at 32 Ok Reg 2270, eff 11-1-15; Amended at 34 Ok Reg 2107, eff 9-15-17; Amended at 35 Ok Reg 2137, eff 9-17-18]