BS EN 10226-1:2004 Pipe threads where pressure tight joints are made on the threads. Taper external threads and parallel internal threads. Dimensions, tolerances and designation
BS EN 10226-1 specifies the requirements for thread form, dimensions, tolerances and designation for jointing pipe threads, sizes 1/16 to 6 inclusive. It applies to joints made pressure tight by means of mating of the threads. These threads are taper external and parallel 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 thread sealant or jointing compound should be used on the thread to ensure pressure-tight joints.
EN 10226-1:2004