This specification covers all standard types of felt in the form of rolls and sheets that are suitable for mechanical use. Certain special-purpose felts are also covered. Felts shall be classified according to thickness and mass, properties and general descriptions. Felt classifications shall be based on the Society of Automotive Engineers Specification and the US Department of Defense Federal Specification. Special-purpose felts shall be classified under special-purpose classification. The chemical properties of roll and sheet felt shall conform to the specified requirements. The physical properties of roll and sheet felt such as width, thickness, and mass (weight) per unit area, shall conform to the requirements specified. All the properties, except color, of felt shall be determined in accordance to the test method specified.

1.1 This specification covers all standard types of felt in the form of rolls and sheets that are suitable for mechanical use. Certain special-purpose felts are also covered.

1.2 This specification is not applicable to felt-like products that utilize weaving, knitting, stitching, or bonding such as papermaker's felt.

1.3 Trade practice in the felt industry deals in pounds, yards, and inches, therefore the values stated in inch-pound units are to be regarded as standard. The values in SI units are provided as information only.

1.3.1 The specification referenced in 2.2 uses only inch-pound units.he percent specific gravity of that class.