1.1This specification covers the requirements for compressible-washer-type direct tension indicators capable of indicating the achievement of a specified minimum bolt tension in a structural bolt.

1.2Four types of direct tension indicators in nominal diameter sizes ¹/₂through 1¹/₂in. are covered:

1.2.1Type 325-direct tension indicators for use with Specification A325 Type 1 bolts or F or F1852 assemblies.

1.2.2Type 325-3-direct tension indicators for use with Specification A325 Type 3 or F1852 Type 3 assemblies.

1.2.3Type 490-direct tension indicators for use with Specification A490 Type 1 bolts or F2280 assemblies.

1.2.4Type 490-3-direct tension indicators for use with Specification A490 Type 3 F2280 Type 3 assemblies.

1.3Direct tension indicators are intended for installation under either a bolt head or a hardened washer. (See Research Council on Structural Connections: Specification for Structural Joints Using ASTM A325 or A490 Bolts.)

1.4This specification provides for furnishing Types 325-3 and 490-3 to a Chemical Composition Requirement or a Corrosion Resistance Index (CRI) at the suppliers option.

1.5The values stated in inch-pound units are to be regarded as standard. No other units of measurement are included in this standard.

1.6The following precautionary statement pertains only to the test method portions, Section 12 and Appendix X1 of this specification: 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 and health practices and determine the applicability of regulatory limitations prior to use.