604.3 Coverings and linings.
MC § 604.3
Coverings and linings, including adhesives where used, shall have a flame spread index not more than 25 and a smoke-developed index not more than 50, when tested in accordance with ASTM E 84 or UL 723, using the specimen preparation and mounting procedures of ASTM E 2231. Duct coverings and linings shall not flame, glow, smolder or smoke when tested in accordance with ASTM C 411 at the temperature to which they are exposed in service. The test temperature shall not fall below 250°F (121.1°C). Coverings and linings shall be listed and labeled. (Am. L.L. 2023/077, 6/11/2023, eff. 6/11/2023) Editor's note: For related unconsolidated provisions, see Appendix A at L.L. 2023/077.











