Haw. Code R. § 6-77-29 - Design formula for steel pipe

(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 gauge.

S = Yield strength in pounds per square inch determined in accordance with section 6-77-30.

D = Nominal outside diameter of the pipe in inches.

t = Nominal wall thickness of the pipe in inches. If this is unknown, it is determined in accordance with section 6-77-31. Additional wall thickness required for concurrent external loads in accordance with section 6-77-28 may not be included in computing design pressure.

F = Design factor determined in accordance with section 6-77-32.

E = Longitudinal joint factor determined in accordance with section 6-77-33.

T = Temperature derating factor determined in accordance with section 6-77-34.

(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 seventy-five percent of the pressure determined under subsection (a) if the temperature of the pipe exceeds 900E F (482E C) at any time or is held above 600E F (316E C) for more than one hour.

Notes

Haw. Code R. § 6-77-29

[Eff ] (Auth: HRS § 269-6) (Imp: 49 C.F.R. §192.105, OCT 1, 1990)