Except where other provisions are made in AD 2000-Merkblatter Series N for pressure vessels made from non-metallic materials, the performance of pressure tests on pressure vessels and pressure-vessel components is covered by the provisions in this AD 2000-Merkblatt. AD 2000-Merkblatt A 4 applies to the pressure-testing of valve bodies. The appropriate AD 2000-Merkblatter in Series W apply to the pressure testing of castings.