602.2.1 Materials within plenums.
MC § 602.2.1
Except as required by Sections 602.2.1.1 through 602.2.1.7, materials within plenums shall be noncombustible or shall be listed and labeled as having 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 E 84 or UL 723. Exceptions: 1. Rigid and flexible ducts and connectors shall conform to Section 603.
2.Duct coverings, linings, tape and connectors shall conform to Sections 603 and 604.
3.This section shall not apply to materials exposed within plenums in one- and two-family dwellings.
4.This section shall not apply to smoke detectors.
5.Combustible materials fully enclosed within one of the following: 5.1. Continuous noncombustible raceways or enclosures. 5.2. Approved gypsum board assemblies. 5.3. Materials listed and labeled for installation within a plenum.
6.Materials in Group H-5 fabrication areas and the areas above and below the fabrication area that share a common air recirculation path with the fabrication area.
