This specification covers the requirements for four types (Types 325, 325-3, 490, and 490-3) of compressible-washer-type direct tension indicators, in nominal diameter sizes ½ through 1 ½ in., capable of indicating the achievement of a specified minimum bolt tension in a structural bolt and are intended for installation under either a bolt head or a hardened washer. Steel materials used in the manufacture of direct tension indicators shall be designed, processed, and protectively coated as specified. The direct tension indicators shall conform to required chemical composition, compression load, and dimensional values.

1.1 This 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.

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

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

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

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

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

1.3 Direct 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.)

1.4 This 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.

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

1.6 The 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.