1.1 This specification covers gypsum board designed to be used as a base in multilayer systems, as a gypsum stud or core in semi-solid or solid gypsum board partitions, or in shaftwall assemblies.

Note 1--Specification C840 contains application procedures for gypsum backing board, gypsum coreboard, and gypsum shaftliner board.

1.2 The values stated in inch-pound units are to be regarded as standard. Within the text, the SI units are shown in brackets. The values stated in each system shal be used independent of the other. Values from the two systems shall not be combined.

1.3 The terms "backing board," "coreboard," and "shaftliner board," refer to different end uses of the gypsum board specified in this specification. The term "gypsum backing board," in this specification, shall include gypsum coreboard and gypsum shaftliner board unless otherwise stated.

1.4 The text of this specification 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 specification.