Maximum Allowable Working Pressure for Standard Pressure Vessels. The maximum allowable working pressure for standard pressure vessels shall be determined in accordance with the applicable provisions of the ASME Code under which they were constructed and stamped.
Where:
TS = ultimate tensile strength of shell plates, psi. When the tensile strength of steel plate is not known, it shall be taken as 55,000 psi for temperature not exceeding 650F.
t = minimum thickness of shell plate of weakest course, inches.
E = efficiency of longitudinal joint, depending upon construction. Use the following values:
For Fusion-Welded and Brazed Joints:
Single lap welded ................................................ 40
Double lap welded............................................... 60
Single butt welded............................................... 60
Double butt welded.............................................. 75
Forge welded........................................................ 70
Brazed steel.......................................................... 80
For riveted joints - calculate riveted joint efficiency in accordance with rules given in Section I, Part PR, of the 1971 Edition ASME Code.
R = inside radius for weakest course of shell, inches, provided the thickness does not exceed 10 percent of the radius. If the thickness if over 10 percent of the radius, the outer radius shall be used.
FS = factor of safety permitted shall be a minimum of 5.0.
Ill. Admin. Code tit. 41, § 2120.500