M-1102.1 General: The following words and terms shall, for the purposes of this chapter and as stated elsewhere in this code, have the meanings shown herein.

Clearance: The minimum distance through air measured between the heat-producing surface of the mechanical appliance, device or equipment and the surface of the combustible material or assembly.

Combustible assembly: Wall, floor, ceiling or other assembly constructed of one or more component materials that are not defined as noncombustible.

Protective assembly (reduced clearance): Any noncombustible assembly that is labeled or constructed in accordance with Table M-1103.3 and is placed between combustible materials or assemblies and mechanical appliances, devices or equipment, for the purpose of reducing required airspace clearances. Protective assemblies attached directly to a combustible assembly shall not be considered as part of that combustible assembly.