4.1 This classification is intended to encourage uniformity in reporting properties of MLS and Metal Layer gaskets, to provide a common language for communications between producers and users, and to guide engineers and designers in the application and construction of commercially available gaskets.

4.2 Suffix Table 2 is provided to allow hardness designation for Active, Inactive, or Load Stoppers.

4.2.1 If suffixes are not to be used, only the basic callout from Table 1 is required. If a suffix is used for 1 layer, it must be specified for all layers, even if a “0” is used. It cannot be assumed that hardnesses of like layers are the same; if used, all layers must be specified separately. The first layer specified must be indicated on the part drawing. To use a hardness call-out, at the end of the base callout leave a space followed by the “HR” suffix with a series of suffix numbers to specify the hardnesses for each layer.

4.2.1.1 Example: ASTM F2325, A32ANBW11 HR252—Example from Table 1 modified to add hardness requirement for the three metal layers. Active layers 1 and 3 are designated to be the same, ¹/₄ hard steel. Stopper layer 2 is designated to be full hard steel.

1.1 This classification covers a means for specifying Multi-Layer Steel (MLS) and other Metal Layer Gaskets for Transportation Applications by application and construction. These structures are composed of one or more steel or metal layers of material, which may have coatings or embossments. Commercial materials designated as composite or enveloped gaskets are excluded from this classification and are covered by Classification F868 and Practice F336, respectively.

1.2 Since all of the properties that contribute to gasket performance are not included, use of this classification as a basis for selecting an MLS or Metal Layer gasket is limited.

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.