A certain pressure vessel manufacturer avoids doing reinforcements calculations for openings by always providing a reinforcing pad extending upto double the diameter of the opening and of the same material and thickness as that of the shell wall. If area compensation is accepted as a code guideline, his approach leads to safe design

• only if the opening is on spherical vessel.
• only if the opening is on a vertical cylinderical vessel.
• only if the opening is on a horizontal cylinderical vessel.
• irrespective of the shape of the vessel.