Sch 1 para 15 Wall thickness
(1) If the product of PS x V is not more than 3 000 bar.L, the manufacturer must select one of the methods described in paragraphs 16 (calculation method) and 17 (experimental method) for determining vessel wall thickness. (2) If the product of PS x V is more than 3 000 bar.L, or if the maximum working temperature exceeds 100°C, such thickness must be determined by the method described in paragraph 16 (calculation method). (3) The actual wall thickness of the cylindrical section and ends must, however, be not less than 2 mm in the case of steel vessels and not less than 3 mm in the case of aluminium or aluminium alloy vessels.