This specification covers the requirements for two types (Types 8.8 and 10.9) of compressible-washer-type direct tension indicators, in nominal diameter sizes M16 through M36, 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, heat treated, and protectively coated as specified. The direct tension indicators shall conform to required chemical composition, compression load, outside diameter, number of protrusions, thickness values, inside diameter, and protrusion tangential diameter values.

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

1.2 Eight types of DTIs in nominal diameter sizes ¹/₂ through 1¹/₂ in. as well as M16 through M36 are covered:

1.2.1 Type 325-1—DTIs for use with Specification A325 Type 1 bolts or F  or F1852 assemblies.

1.2.2 Type 325–3—DTIs for use with Specification A325 Type 3 bolts or F1852 Type 3 assemblies.

1.2.3 Type 490–1—DTIs for use with Specification A490 Type 1 bolts or F2280 assemblies.

1.2.4 Type 490–3—DTIs for use with Specification A490 Type 3 F2280 Type 3 assemblies.

1.2.5 Type 8.8-1—DTIs for use with Specification A325M Type 1 bolts.

1.2.6 Type 8.8-3—DTIs for use with Specification A325M Type 3 bolts.

1.2.7 Type 10.9-1—DTIs for use with Specification A490M Type 1 bolts.

1.2.8 Type 10.9-3—DTIs for use with Specification A490M Type 3 bolts.

1.3 DTIs are intended for installation under either a bolt head or a hardened washer. (See Research Council on Structural Connections: Specification for Structural Joints Using High–Strength Bolts.)

1.4 This specification provides for furnishing Type 3 DTIs to a Chemical Composition Requirement or a Corrosion Resistance Index (CRI) at the manufacturer’s discretion.

1.5 Terms used in this specification are defined in Terminology F1789 unless otherwise specified.

1.6 The following precautionary statement pertains only to the test method portions, Section 10 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.