6.3.6 Compensation for openings in the water header
The thickness calculated for the hemispherical part of the water head is based on a vessel wall without openings. Any openings, such as the branches and access door, have to be allowed for by thickening the walls adjacent to the openings (Figs 3.47 and 3.48). The amount of the compensation is found by application of Clause 3.5.4 of BS5500 . Since the amount of compensation will vary with individual manufacturer's designs, a specific example is not given here.