An extruded outlet header is a branch connection formed by extrusion, using a die or dies to control the radii of the extrusion. Paragraph 304.3.4 provides area replacement rules for such connections; they are applicable for 90-deg. branch connections where the branch pipe centerline intercepts the run pipe centerline, and where there is no additional reinforcement. Figure 4.8 (ASME B31.3, Fig. 304.3.4) shows the geometry of an extruded outlet header. Extruded outlet headers are subject to minimum external contour radius requirements, depending on the diameter of the branch connection.
A similar area replacement calculation is used as described in Section 4.4 for fabricated branch connections,except that the required replacement area is reduced for smaller branch-to-run pipe diameter ratios. The replacement area is from additional metal in the branch pipe, additional metal in the run pipe, and additional metal in the extruded outlet lip. #Little_PEng.