Welded branch connections shall be designed as specified in the following Items a) to d), whichever is applicable, as given in Table 4.6. Where reinforcement is required, such connections shall also be designed as specified in the following Items e) and f):
a) Where practical, smoothly contoured, wrought steel tees and crosses of proven design or integrally reinforced extruded outlet headers shall be used. Where it is not practical to use such tees, crosses, or headers, the reinforcement shall be a complete encirclement type (see Figure 4.3). Where practical, the inside edges of the finished opening shall be rounded to a 3 mm radius. Where the encircling reinforcement is thicker than the run pipe wall and its ends are to be welded to the run pipe, the ends shall be tapered to a thickness not in excess of two times the run pipe wall thickness, and continuous fillet welds shall be made. Pads, partial saddles, and other types of localized reinforcement shall not be allowed.
b) The reinforcement shall be a complete encirclement type (see Figure 4.3), pad type, saddle type (see Figure 7.4), or welding outlet fitting type. Where attached to the run pipe by fillet welding, the edges of the reinforcement member shall be tapered to a thickness not in excess of two times the run pipe wall thickness.
c) Reinforcement shall not be required for openings suitable to accommodate 60.3 mm OD branch pipe and smaller; however, suitable protection against vibration and other external forces to which these small openings are frequently subjected shall be provided.
d) Reinforcement shall not be mandatory; however, reinforcement might be necessary for special cases involving pressures over 700 kPa, thin-wall pipe, or severe external loads.
e) Where the branch pipe diameter is such that a localized type of reinforcement would extend around more than one-half of the circumference of the run pipe, one of the following shall be used:
i) a complete encirclement type of reinforcement;
ii) a smoothly contoured wrought steel tee or cross of proven design; or
iii) an extruded outlet header.
f) Reinforcements shall be designed as specified in Clauses 4.3.19 and 4.3.20.
CSA Z662-15 (Oil and gas pipeline systems)
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