This specification covers either untextured or surface textured non-asbestos fiber-cement flat sheets intended for exterior applications such as claddings, facades, curtain walls, soffits, and so forth. This specification does not apply to asbestos-cement flat sheets, gypsum-based boards or particle boards, discrete non-asbestos fiber-cement interior substrate sheets, fiber-mat reinforced non-asbestos cement interior substrate sheets, or cement-bonded particleboards. Flat sheets covered here are divided into two types according to their intended application, and four grades according to their flexural strengths. Type A sheets are intended for exterior applications subjected to the direct action of sun, rain, or snow, while Type B sheets are intended for exterior applications not subjected to the direct action of sun, rain, or snow. Sheets shall adhere to the following mechanical and physical requirements: flexural strength, density, dimension (nominal length, width, and thickness, squareness, and edge straightness), finish, and color.

1.1 This specification covers either untextured or surface textured fiber-cement flat sheets intended for exterior applications such as claddings, facades, curtain walls, soffits, and so forth.

1.2 This specification is not applicable to asbestos-cement flat sheets (Specification C220), gypsum-based boards (Specifications C1396/C1396M, C1177/C1177M, C1178/C1178M), or particle boards (Terminology D1554) discrete non-asbestos fiber-cement interior substrate sheets (Specification C1288), fiber-mat reinforced non-asbestos cement interior substrate sheets (Specification C1325), 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.

1.4 The text of this standard references notes and footnotes which provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the standard.