Standards 39: Threaded & Socket Welded Fittings – Pressure Classes and Schedules
Threaded & Socket Welded Fittings – Pressure Classes and Schedules Pressure classes, schedules and weights of pipes for threaded & socket welded fittings
Standard (STD), Extra Strong (XS) and Double Extra Strong (XXS) Schedule – Numbers assigned to different wall thicknesses of pipe (i.e. schedule 80)
Related reading
Series: Piping Standards Series | Previous: Standards 38: Steel Tubes according BS 1387 | Next: Standards 40: European Committee for Standardization CEN/TC 69 – Published standards