General (2011) All materials subject to test and inspection@ intended for use in the construction of the hulls of craft classed or proposed for classification@ are to be tested by the material producer and inspected by the ABS Surveyor in accordance with the following requirements or their equivalent. These requirements are not applicable to the use of aluminum alloys at low temperature for cryogenic applications. Materials@ test specimens and mechanical testing procedures having characteristics differing from those prescribed herein may be approved for application@ with due regard being given to established practices in the country in which the material is produced and the purpose for which the material is intended@ such as the parts for which it is to be used@ the type of craft and intended service@ and the nature of the construction of the craft. The requirements are based on both metric and U.S. customary units. Each system of units is to be treated as separate and independent from the other. Mixing and matching of units from one system to another are not permitted. The numerical designation (grade) of aluminum alloys and the temper designation are based on those of the Aluminum Association or recognized Standards. All materials@ including semi-finished products are to be manufactured at works which are approved by ABS for the grades and maximum thickness of aluminum alloy supplied.