scope:

This British Standard specifies requirements for the following pipe threads.

a) Jointing threads, which are pipe threads for joints made pressure-tight by the mating of the threads and are taper external, taper internal or parallel internal threads.

NOTE1 Parallel external pipe threads are not suitable as jointing threads.

b) Longscrew threads, which are parallel pipe threads used for longscrews connectors) specified in BS 1387 where a pressure-tight joint is achieved by the compression of a soft material on to the surface of the external thread by tightening a backnut against a socket.

Thread sized from ¹/₁₆ to 6 inclusive are covered by this standard and requirements for thread forms, dimensions and tolerances are given, together with the designation of each type of thread.

NOTE2 Appendix B gives methods of verification of jointing thread dimensions and form using recommended gauging systems described in APPENDIX A.

NOTE3 Reference should be made to BS 2779 for requirements for pipe threads where pressure-tight joints are not made on the threads.

NOTE4 The titles of the publications referred to in this standard are listed on the inside back cover.