Minn. R. agency 151, ch. 1346, MINNESOTA MECHANICAL CODE, pt. 1346.0703

Current through Register Vol. 49, No. 20, November 12, 2024

Part 1346.0703 - SECTION 703 OUTDOOR AIR

IMC Sections 703.1 through 703.1.2.2 are amended to read as follows:

703.1 All air from the outdoors. Where all combustion and dilution air is to be provided by outdoor air, the required combustion and dilution air shall be obtained by opening the room to the outdoors. Openings connecting the room to the outdoor air shall comply with IMC Sections 703.1.1 through 703.1.2.2.

703.1.1 One permanent opening method. When any natural draft equipment is installed, one permanent opening, commencing within 12 inches (300 mm) of the bottom of the enclosure, shall be provided. When other than natural draft equipment is installed, one permanent opening, commencing within 12 inches (300 mm) of the top of the enclosure, shall be provided. The opening shall directly communicate with the outdoors or shall communicate through a vertical or horizontal duct to the outdoors or spaces that freely communicate with the outdoors and shall have a minimum free area of 1 inch²/3,000 Btu/hr (700 mm²/kW/hr) of the total input rating of all equipment located in the enclosure.

703.1.2 Two permanent openings method. Two openings shall be provided, one within 1 foot (305 mm) of the ceiling of the room and one within 1 foot (305 mm) of the floor.

703.1.2.1 Size of horizontal openings. The net free area of each opening, calculated in accordance with IMC Chapter 709 and connected to the outdoors through a horizontal duct, shall be a minimum of 1 square inch per 2,000 Btu/h (1,100 mm²/kW) of combined input rating of the fuel-burning appliances drawing combustion and dilution air from the room. The cross-sectional area of the duct shall be equal to or greater than the required size of the opening.

703.1.2.2 Size of vertical openings. The net free area of each opening, calculated in accordance with IMC Chapter 709 and connected to the outdoors through a vertical duct, shall be a minimum of 1 square inch per 4,000 Btu/h (550 mm²/kW) of combined input rating of the fuel-burning appliances drawing combustion and dilution air from the room. The cross-sectional area of the duct shall be equal to or greater than the required size of the opening.

Minn. R. agency 151, ch. 1346, MINNESOTA MECHANICAL CODE, pt. 1346.0703

29 SR 299; L 2007 c 140 art 4 s 61; art 13 s 4; 34 SR 537

Statutory Authority: MS s 16B.59; 16B.61; 16B.64; 326B.101; 326B.106; 326B.13