Minn. R. agency 151, ch. 1346, MINNESOTA MECHANICAL CODE, pt. 1346.0607
Current through Register Vol. 49, No. 20, November 12, 2024
Part 1346.0607 - SECTION 607, DUCT AND TRANSFER OPENINGS IMC section 607.6.1 is amended to read as follows:
607.6.1 Through penetrations. In occupancies other than Group I-2 and I-3, a duct constructed of approved materials in accordance with this code that penetrates a fire-resistance-rated floor or floor/ceiling assembly that connects not more than two stories is permitted without a shaft enclosure protection, provided a listed fire damper is installed at the floor line or the duct is protected in accordance with IBC section 714.4, as amended. For air transfer openings, see IBC section 712.1.8, as amended. Exceptions:
1. A duct is permitted to penetrate three floors or less without a fire damper at each floor, provided such duct meets all of the following requirements: a. The duct shall be contained and located within the cavity of a wall and shall be constructed of steel having a minimum wall thickness of 0.0187 inches (0.4712 mm) (No. 26 gage) or the duct shall be protected by an approved through-penetration firestop system installed and tested in accordance with ASTM E 814 or UL 1479. The approved through-penetration firestop system shall have an F rating or T rating of not less than the required rating of the horizontal assembly being penetrated.b. The duct shall open into only one dwelling unit or sleeping unit and the duct system shall be continuous from the unit to the exterior of the building.c. The duct shall not exceed 4-inch (102 mm) nominal diameter and the total area of such ducts shall not exceed 100 square inches (0.065 m2) in any 100 square feet (64,516 mm2 per 9.3 m2) of the floor area.d. The annular space around the duct is protected with materials that prevent the passage of flame and hot gases sufficient to ignite cotton waste where subjected to ASTM E 119 or UL 263 time-temperature conditions under a minimum positive pressure differential of 0.01 inch (2.49 Pa) of water at the location of the penetration for the time period equivalent to the fire-resistance rating of the construction penetrated.e. Grille openings located in a ceiling of a fire-resistance-rated floor/ceiling or roof/ceiling assembly shall be protected with a listed ceiling radiation damper installed in accordance with IBC section 717.6.2.1, as amended.2. In Group I-2 and I-3 occupancies, a duct constructed of approved materials in accordance with this code that penetrates a fire-resistance-rated floor or floor/ceiling assembly that connects not more than two stories is permitted without a shaft enclosure protection, if a listed smoke/fire damper is installed at the floor line.Minn. R. agency 151, ch. 1346, MINNESOTA MECHANICAL CODE, pt. 1346.0607