This specification covers staple or continuous filament carbon/graphite yarn valve stem compression packing, suitable for use as end-rings on packing systems for valves. Intended services include steam, hydrocarbons, water and non-oxidizing chemicals. The material shall be of the following types, classes, and grades: Type I, type II, and Type III; Class 1; Class 2; and Class 3; and Grade A and Grade B. The following tests shall be performed: size; mass; carbon assay; ash content; specific gravity; moisture content; detrimental materials tests; analysis of PTFE coating; compression recovery; and braid geometry retention.

1.1 This specification covers staple or continuous filament carbon/graphite yarn valve stem compression packing, suitable for use as end-rings on packing systems for valves. Intended services include steam, hydrocarbons, water, and non-oxidizing chemicals. Where this specification is invoked as ASTM F2191/F2191M, Sections 1 – 18 apply. Where this specification is invoked as ASTM/DoD F2191/F2191M, Sections 1 – 18 and the Supplementary Requirements shall be applicable.

1.2 The values stated in either SI units or inch-pound 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 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.

1.4 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.