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 1 1/2 in. are covered:

1.2.1 Type 325—direct tension indicators for use with Specification A 325 or F 1852 Type I bolts, nuts, and washers.

1.2.2 Type 325–3—direct tension indicators for use with Specification A 325 Type 3 bolts, nuts, and washers.

1.2.3 Type 490—direct tension indicators for use with Specification A 490 or F 2280 bolts, nuts, and washers.

1.2.4 Type 490–3—direct tension indicators for use with Specification A 490 Type 3 bolts, nuts, and washers.

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 A 325 or A 490 Bolts.)

1.4 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.