Two or more straight sections of pipe matched and joined on a line bisecting the angle of junction so as to produce produce a change in direction. The thickness thickness of each segment segment of a miter must must be designed in the same manner as straight pipe. The thickness, however, does not allow for the discontinuity stresses that exist at junctions between the segments of a miter. These stresses are reduced for a given miter as the number of segments is increased. An angular offset of 3_ or less does not require design considerations as a miter bend, and the same design basis applies as is used for straight pipe. The Code requires multiple miter bends with miter angle cuts not greater than 22.5_, which requires a minimum of 2 miter cuts to achieve a short‐ pattern full 90_ bend. Single miter bends are allowed with a miter cut angle greater than 22.5_, but different design rules apply. Miters in process plants are typically limited to relatively large diameter and low‐pressure [50 psig (345 kPa) or less] piping systems, especially where elbow fittings are not readily available. Even for these services, 90_ miter bends should have three or more segments. Refer to Fig. C7.4. The wall thickness of mitered segments of pipe subjected to external pressure must be designed designed in the same manner as required for straight pipe.
