This standard covers dimensionally stable discrete non-asbestos fiber-cement interior substrate sheets suitable for decoration as paint, wallpaper, natural stone, tile, or resilient flooring in internal wet and dry areas. The list of materials for this specification does not include asbestos-cement flat sheets, non-asbestos fiber-cement flat sheets used for claddings, facades, curtain walls, and soffits, gypsum backing boards and coreboards, water-resistant gypsum backing boards, glass mat gypsum backing boards, fiber mat cement boards, or cement-bonded particleboards. The sheets may be coated or uncoated and are classified into four grades according to flexural strength. Materials should essentially consist of an inorganic binder or a calcium silicate binder and optional compatible process aids, fillers, and pigments. To meet property requirements, the products may be formed with or without pressure and cured under natural or accelerated conditions. All products should conform to the required values of flexural strength, density, and modulus of elasticity, and to the qualities of workmanship, finish, and appearance.

1.1 This specification covers discrete non-asbestos fiber-cement sheets manufactured to be dimensionally stable and suitable for decoration as paint, wallpaper, natural stone, tile, or resilient flooring in internal wet and dry areas.

1.2 This specification is not applicable to asbestos-cement flat sheets (Specification C220), non-asbestos fiber cement flat sheets for exterior applications such as claddings, facades, curtain walls, and soffits (Specification C1186), gypsum backing board and coreboard (Specification C442/C442M), water-resistant gypsum backing board (Specification C630/C630M), glass mat gypsum backing board (Specification C1178/C1178M), particle boards (Definitions D1554), fiber mat cement boards (Specification C1325 and ANSI A118.9), or cement-bonded particleboards (Specification BS 5669: Part 4) and (ISO 8335).

1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.