scope:

This standard pertains primarily to cast and forged steel flanges; but the flange dimensions, bolting, minimum wall thicknesses, and certain other requirements herein specified apply also to cast, forged, and fabricated steel flanged valves and fittings of corresponding pressure class and size.

This standard covers:

(a) Pressure-Temperature Ratings

(b) Sizes¹ and Methods of designating openings

(c) Marking

(d) Minimum requirements for materials

(e) Dimensions¹

(f) Tolerances

(g) Tests

Standards and specifications adopted by reference in this Standard and the names and addresses of the sponsoring organizations are shown in Appendix H. It is not considered practical to refer to a specific edition of each of the standards and specifications in the individual references. Instead the specific edition references are included in Appendix H. A product made in conformation with the edition reference applicable during time of manufacture and in all other respects conforming to this standard will be considered to be in conformance even though the edition reference may be changed in a subsequent revision of this standard.

The pressure-temperature ratings included in this standard are applicable upon its publication to all products covered withing its cope which otherwise meet its requirements. However, where such components were purchased, manufactured, or installed under the pressure-temperature ratings of ANSIb16.5-1968, those ratings shall apply except as may be governed by the applicable Code.

¹ The use of the word "nominal" as a modifier of a dimension or size is intended to indicate that the stated dimension or size is used for purposes of designation. The actual dimension may be the nominal dimension subject to the variation of established tolerances.