DS EN 10226-2:2006 Pipe Threads Where Pressure Tight Joints Are Made On The Threads - Part 2: Taper External Threads And Taper Internal Threads - Dimensions, Tolerances And Designation Defines 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.