For each of the following problem, check the applicability of the thin-wall theory. Unless...

For each of the following problem, check the applicability of the thin-wall theory. Unless otherwise noted, the stated diameter represents an inside diameter.

The longitudinal joint in an 8-ft-diameter closed cylindrical steel boiler is butt welded with a joint efficiency of 85 percent. The boiler plate is thick with an allowable tensile stress of 11,000 psi. Calculate the maximum safe internal pressure.