This specification covers casting and molding plaster materials consisting essentially of calcined gypsum. The chemical composition of each plaster material should meet the required purity value. For samples, equal amounts of material should be taken from the outer and center of each package. Specimens shall also be tested for setting time, compressive strength and fineness.

1.1 This specification covers gypsum casting plaster and gypsum molding plaster materials consisting essentially of calcined gypsum.

1.2 The values stated in either inch-pound or SI units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.

1.3 The text of this standard references notes and footnotes that provide explanatory material. These notes and footnotes shall not be considered as requirements of the standard.

1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.