Minn. R. agency 151, ch. 1346, MINNESOTA MECHANICAL CODE, pt. 1346.0604

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

Part 1346.0604 - SECTION 604 INSULATION

Subpart 1.Section 604.1.

IMC section 604.1 is amended to read as follows:

604.1General. Duct insulation shall conform to the requirements in Minnesota Rules, chapter 1322 or 1323, as applicable.General. Duct insulation shall conform to the requirements in Minnesota Rules, chapter 1322 or 1323, as applicable.

Subp. 2.Section 604.3.

IMC section 604.3 is amended to read as follows:

604.3 Coverings and linings. Coverings and linings, including adhesives where used, shall have a flame-spread index of not more than 25 and a smoke-developed index of not more than 50, when tested in accordance with ASTM E84 or UL 723, using the specimen preparation and mounting procedures of ASTM E2231. Duct coverings and linings shall not flame, glow, smolder, or smoke when tested in accordance with ASTM C411 at the temperature to which they are exposed in service. The test temperature shall not fall below 250°F (121°C). Coverings and linings shall be listed and labeled.

Exception: Spray polyurethane foam without additional ignition barrier or thermal barrier protection shall be permitted as a duct covering where duct construction in compliance with Table 603.4 is installed in a floor assembly over an unconditioned space in IRC-1, IRC-2, or IRC-3 occupancies, as defined in Minnesota Rules, part 1300. 0070, subpart 12b, provided the spray polyurethane foam meets all of the following requirements:

1. Spray polyurethane foam shall have a medium density classification (2 lbs./cubic ft., closed cell foam);2. Spray polyurethane foam shall have an R-value of not less than R-8; and3. Spray polyurethane foam shall have a flame-spread index of 25 or less and a smoke-developed index of 450 or less when tested in accordance with ASTM E84 or UL 723.

Minn. R. agency 151, ch. 1346, MINNESOTA MECHANICAL CODE, pt. 1346.0604

15 SR 71; 29 SR 299; L 2007 c 140 art 4 s 61; art 13 s 4; 34 SR 537; 44 SR 1085

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