MSS SP-97 Standard Practice covers essential dimensions, finish, tolerances, testing, marking, material, and minimum strength requirements for 90 degree integrally reinforced forged branch outlet fittings of buttwelding, socket welding, and threaded types. Integrally Reinforced Forged Branch Outlet Fittings – Socket Welding, Threaded, and Buttwelding Ends. Fittings manufactured to this Standard Practice are designed to make a fully reinforced branch connection in accordance with applicable piping code requirements, when attached, at an opening in a run pipe by means of a full penetration weld.
Fittings may be made to special dimensions, size, shape, tolerances, or of other wrought material by agreement between the manufacturer and the purchaser.
MSS
MSS(Manufacturers Standardization Society) is the only organization in the world dedicated exclusively to the technical needs of the valve and fittings industry.
Standards and codes are written and revised by 25 technical committees and address topics such as valves, valve actuators, pipe fittings, flanges, and pipe hangers.
6.1 A run pipe having a branch connection is weakened by the opening made in it. The branch connection must reinforce the opening and restore the original strength of the run pipe. It is the intent of this Standard Practice that these integrally reinforced branch outlet
fittings and the deposited weld metal used to attach the fittings to run pipes contain all the reinforcement required by the applicable pressure vessel or piping codes without the addition of saddles or pads.
6.1.1 The adequacy of the design of branch connection fittings may be established by mathematical analyses contained in pressure vessel or piping codes, or, at the manufacturer's option, by proof testing in accordance with Section 7 and Annex B.
Records of design or proof tests shall be available at the manufacturer's facility for inspection by the purchaser.
6.1.2 The pressure vessel or piping codes referred to in Section 6.1.1 permit a variety of attachment welds for these fittings. Typical branch attachments are shown in ASME B31.1 and B31.3.
6.1.3 Fittings shall be contoured to provide a good fit at the opening in the run pipe. The run attachment weld bevel angle design will vary with the size and type of fitting and with the manufacturer. The size of the run opening is dependent on the manufacturer's
specification.
6.2 Buttwelding Buttwelding end finishes shall comply with the standard welding bevel and root face of ASME B16.25.
6.3 Threads Threads in threaded fittings shall comply with ASME B1.20.1 requirements for NPT.
