Applies to cylinders having a water capacity exceeding 4 fl oz but not exceeding 1500 lb. Material requirements for low carbon (two tensile strengths), normal carbon and low alloy high tensile steel are specified. For the low alloy steel, two design stresses are provided, the higher stress being limited to cylinders up to 15 in. diameter. The design formula for calculating minimum thickness of wall and end is given and a range of tests for the parent metal and the welded joint is prescribed. A hydrostatic test on the cylinder is also required.