Wis. Admin. Code Department of Safety and Professional Services SPS 341.71
Secondhand boilers and secondhand pressure vessels, originally installed in Wisconsin and not constructed and stamped according to some edition of the ASME code, may be reinstalled if the maximum allowable working pressure is recalculated with a factor of safety of 6.
Note: The pressure calculation formula for shells is as follows:
P = (T.S. x t x E)/(R x F.S.)
where P = maximum allowable working pressure, pounds per square inch
T.S. = tensile strength of shell plate, pounds per square inch
t = minimum thickness of shell plates, inches
E = efficiency of longitudinal joint
R = inside radius of the outside course of the shell, inches
F.S. = factor of safety
Note: The pressure calculation formula for flat heads and flat surfaces is as follows:
P = (T.S. x t2)/(0.5 x d2 x F.S.)
where P = maximum allowable working pressure, pounds per square inch
T.S. = tensile strength of shell plate, pounds per square inch
t = thickness of plate, inches
d = diameter of head or shortest unsupported span of head or maximum pitch between stays, inches
F.S. = factor of safety
Wis. Admin. Code Department of Safety and Professional Services SPS 341.71