S9074-AR-GIB-010/278
7.)
Class P-1 piping butt joints shall be designed, welded, and inspected to assure complete weld penetration. P-1 piping butt joints in submarine seawater systems shall be the consumable insert type except that backing rings may be used for closure welds where allowed by drawings or specifically approved. Joint P-73 may have 8 = 45 degrees plus or minus 5 degrees for copper-nickel seawater systems. Joints P-13, P-14. and P-15 shall be limited to 2- inch nps and smaller for class P-1 piping systems (except that socket weld designs shall not be used in systems where 100,000 or more cycles of pressure variation, of more than 2/3 normal operating pressure, are expected, and a reference mark suitably located shall be established as a benchmark for verifying fillet weld size by an appropriate gauge measuring device. Joints such as P-3, P-13, P-14, and P-15 shall not be permitted on materials subject to crevice corrosion except as permitted by footnote 10. Except as permitted by footnote 10, joints such as P-1, P-2, P-12, P-60, P-61, P-62, P-67, and P-68 shall not be permitted on materials subject to crevice corrosion unless the inside surface of the weld is visually inspected to assure complete weld penetration. Joints addressed by footnotes 8 and 9 are satisfactory for use in seawater service when the material of fitting and pipe is copper-nickel, 70-30 or 90-10 alloys or a combination of both.
8.)
9.)
10.)
P-67 joint and P-68 joint 4 inches and smaller welded from one side only may be used for class P-1 where the following conditions are met:
11.)
(a) Branch connection fit-up, welding processes, and final inspection ensures complete root penetration and an acceptable weld content on the inner surface. Welding of such joints requires welding procedures and the welder's qualifications in accordance with MIL-STD-248. (b) The PT or MT (as applicable) inspection methods shall be used for the root weld layer and both final weld surfaces. Visual examination at 5X magnification may be substituted for MT/PT of the root weld pass in the grooved side.
12.)
P-42 joints shall not be used with butterfly valves, spriral wound gaskets, or flanged joints in oil systems.
13.)
Unreinforced branch connections such as P-60, P-61, P-62, P-63, and P-64 joints shall not be used in any systems where the design gauge pressure is over 150 lb/in2 or the design mature is over 449°F. Reinforcement shall not be obtained by weld buildup and any branch connection fabricated by the use of welding only shall be considered as unreinforced.
14.) See 9.3.2.1
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