Description

This Standard covers designation system, dimensions and gauging of four series of pipe screw threads in the range 4 to 150 mm (1/16 to 6 in) nominal size (bore), suitable for connecting pipes used for conveying fluids, with sealing being effected on the thread surfaces in contact. The series are internal taper (Series RC), internal parallel (Series RP), external taper (Series R) and external parallel (Series RL).

Scope

This standard specifies the geometry of screw threads suitable for connecting pipes (tubes) used for conveying fluids.

It is based on ISO 7 and covers taper and parallel thread varieties, intended for sealing on the thread because of the taper. It also includes parallel external threads of the Longscrew Series of BS 21:1973, Pipe Threads for Tubes and Fittings where pressure-tight Joints are made on the threads (see Clause 2.2.5).

The standard covers the range of nominal bore sizes 1/16 in (4 mm) to 6 in (150 mm) both inclusive.