S9074-AR-GIB-010/278
in piping systems which transmit oxygen, helium, mixed gases, air, water and exhaust of diving life support systems. Also included are any structural welds made to the internal or external surfaces of a fluid boundary subject to system pressure but which do not form a part of the fluid boundary. This includes any weld made to a weld deposited pad or cladding on the fluid boundary as well as the weld deposited pad or cladding beneath the weld itself. This does not include cladding other than cladding beneath the weld nor does it include welds which join clips, nameplates. insulation supports, or other nonstructural members to the fluid boundary. Specifically excluded are pipe joints meeting the classification criteria of class P.LT. (2) Class P-2. Class P-2 includes fabrication welds for design pressures and design temperatures not exceeding 300 lb/in2 and 650°F. Also included are fabrication welds in all open ended vent, drain and steam escape piping that has no isolation capability from its origin to its terminus regardless of the design temperature or pressure. Specifically excluded are pipe joints meeting the classification criteria of class P- LT. (3) Class P-LT. Class P-LT includes fabrication welds for all piping of design pressures greater than 50 lb/in2 and service temperatures of minus 20°F and below. (4) Class P-3. Class P-3 piping includes all brazed piping of unlimited pressures and 425°F maximum design temperature. Fabrication and inspection of brazed piping systems shall be in accordance with NAVSEA 0900-LP-001-7000. (c) Pressure vessels and tanks. class A. Class A pressure vessels and tanks include the fabrication welds for parts of drums, tanks, or closed receptacles (including nozzle attachments) and valves which are designed to contain gases or liquids. This includes all feed tanks. lubricating 011 storage tanks, and similar vessels which contain only the static head of the obtained liquid. It does not include tubing or piping that joins to the pressure vessel, which are subject to the requirements of class P piping. Valves to be installed in class P-1 piping system shall be fabricated and inspected in accordance with class A-2 pressure vessel requirements. Valves to be installed in other classes of piping systems shall be fabricated and inspected in accordance with the appropriate pressure vessel category as determined by design temperatures and pressures. (1) Class A-F. Class A-F includes fabrication welds for fired and unfired pressure vessels for all pressures and temperatures that are specifically designed for a finite fatigue life and, as a consequence, are required to undergo low cycle fatigue evaluations. Also included are any structural welds made to the internal or external surfaces of a fluid boundary subject to system pressure but
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