Rp, internal parallel (ISO 7/1).
This part of ISO 7 specifies the requirements for thread form, dimensions, tolerances and designation for jointing pipe threads, sizes 1/16 to 6 inclusive, for joints made pressure-tight by the mating of the threads. These threads are taper external, parallel internal or taper internal and are intended for use with pipes suitable for threading and for valves, fittings or other pipeline equipment interconnected by threaded joints.
An appropriate jointing medium should be used on the thread to ensure pressure-tight joints.
NOTES
1 Parallel external pipe threads are not suitable as jointing threads.
2 For pipe threads where pressure-tight joints are not made on the threads, see ISO 228-1.
3 ISO 7-2 gives details of methods of verification of jointing thread dimensions and form and recommended gauging systems.
