ASTM C1858-17a

5.1 This practice provides a standardized installation procedure for ceilings designed and installed as a diaphragm. When installed according to this practice, these ceilings have sufficient strength to resist seismic forces without lateral force bracing.

1.1 This practice covers the installation requirements of direct hung suspended t-bar type ceiling systems intended to receive gypsum panel products constructed as flat, single level, surrounded on all sides by a wall, bulk head, or soffit braced to the building structure to resist the effects of earthquake ground motions.

1.2 Ceiling assembly shall not be intended to support live loads.

1.3 This standard addresses ceiling systems with dead loads up to 10 lbs/ft² (48.8 kg/m²).

1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.

1.5 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

1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.7 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.