Copper pipe may not be threaded except thatfor copper pipe that is used for joining screw fittings or valves, which may be threaded if the wall thickness is equivalent to the comparable size of Schedule 40 or heavier wall pipe listed in TableASME C1B36.10M of(incorporated ASME/ANSIby B16reference, see § 192.57). [Amdt. 192-62135, 5489 FR 562833281, FebApr. 629, 1989, as amended at 58 FR 14521, Mar. 18, 19932024]