3.6.5.5.Insulation and Coverings

(1) Insulation and coverings on pipes in which the temperature of the fluid exceeds 120°C shall (a) be made of noncombustible material, or (b) not flame, glow, smoulder or smoke when tested in accordance with ASTM C411, “Standard Specification for Hot- Surface Performance of High-Temperature Thermal Insulation,” at the maximum temperature to which the insulation or covering is to be exposed in service. (2) Except as permitted by Sentence (5), where combustible insulation is used on piping in a horizontal service space or a vertical service space, the insulation and coverings on that piping shall have a flame-spread rating, on any exposed surface and on any surface that would be exposed by cutting through the material in any direction, (a) not more than 25 in a building required to be of noncombustible construction or in a building or part of a building permitted to be of encapsulated mass timber construction, or (b) not more than 75 in a building permitted to be of combustible construction. (3) Except as permitted by Sentence (5), insulation and coverings on piping located in rooms and spaces other than the service spaces described in Sentence (2) shall have a flame-spread rating not more than that required for the interior finish of the ceiling of the room or space. (4) Except as permitted by Sentence (5), combustible insulation and covering used on piping in a building within the scope of Subsection 3.2.6. shall have a smoke developed classification not more than 100. (5) No flame-spread rating or smoke developed classification limits are required for combustible insulation and coverings used on piping located within a (a) concealed space in a wall, (b) floor slab, or (c) noncombustible enclosure.