CodeCalc determines the volume of the vessel as well as the empty and full weights. These weights are computed with the vessel in the corroded condition. Knowing the weights may be useful for cost estimating and for design of supporting attachments, such as lifting lugs.
The longitudinal stresses displayed in the output include the stresses due to internal pressure. Since these are normal stresses they are added together. The allowable tension is the basic operating allowable times the joint efficiency. The compressive allowable is the factor B taken from UG-23 using the materials chart for the given material.
The tangential shear in the shell varies depending on whether the shell is stiffened or the head acts as a stiffener, or neither of these cases. Tangential stress in the head only exists if the head is close enough to the saddle to be used as a stiffener. The allowable stress in shear is 80% of the allowable tensile stress for the head or shell.
The stress at the horn of the saddle depends on the location of the saddle and the equivalent thickness of the saddle and wear pad. It is zero if rings stiffen the shell. This stress is always compressive and the allowable stress is a negative of the minimum of 1.5 times the allowable tensile stress and 0.9 times the yield stress.
Use of the head as a stiffener creates additional tension stress in the head. The allowable additional stress in the vessel head is limited to 0.25 times the allowable tension stress in the head. If pressure is added, the resulting stress must be less than 1.25 times the allowable tensile stress.
If the tip of the stiffening ring is in compression, its allowable will be -0.5 times the yield stress. If a tensile condition exists, the basic material allowable will be used.