Tensile and bending tests
86.—(1)  The tensile strength shall not exceed 28 tons per square inch, and the elongation, measured on a standard test‑piece A, shall not be less than 20% if the thickness of the tube is ¼ inch and over; or not less than 18% if the thickness of the tube is less than ¼ inch.
(2)  The bending tests shall be as prescribed in rule 57(1) for boiler plates.