Specifies the aluminium alloy designation 7060 to bring the Standard into line with European practice, where it is now commonly used in cylinder production. The 7060 alloy, when using the existing ratios in this Standard, gives an ultimate design stress ratio some 4 percent higher than the other existing 6351 and 6061 alloys. It is also recognized that the safety factor on burst is marginally higher than the other alloys.