(a) The design pressure for steel pipe is determined in accordance with the following formula: P = (2 St/D) x F x E x T P = Design pressure in pounds per square inch (kPa) gauge.S = Yield strength in pounds per square inch (kPa) determined in
accordance with Sec. 192.107.D = Nominal outside diameter of the pipe in inches (millimeters).t = Nominal wall thickness of the pipe in inches (millimeters). If this
is unknown, it is determined in accordance with Sec. 192.109.
Additional wall thickness required for concurrent external
loads in accordance with Sec. 192.103 may not be included in
computing design pressure.F = Design factor determined in accordance with Sec. 192.111.E = Longitudinal joint factor determined in accordance with
Sec. 192.113.T = Temperature derating factor determined in accordance with
Sec. 192.115.
(b) If steel pipe that has been subjected to cold expansion to meet the SMYS is subsequently heated, other than by welding or stress relieving as a part of welding, the design pressure is limited to 75 percent of the pressure determined under paragraph (a) of this section if the temperature of the pipe exceeds 900 F (482 C) at any time or is held above 600 F (316 C) for more than 1 hour. [35 FR 13257, Aug. 19, 1970, as amended by Amdt. 192-47, 49 FR 7569, Mar. 1, 1984; Amdt. 192-85, 63 FR 37502, July 13, 1998]