Pipe Bending

During a recent Mechanical Integrity Inspection, I ran across a pipe that had been bent to facilitate proper joining during installation. My instinct was to view the bent pipe as a Mechanical Integrity deficiency. After reviewing the most current Refrigeration Piping Code (ASME B31.5 §529) I learned that pipe bending is allowed within the limitations defined in the code. Here’s a quick summary of a few ASME B31.5 requirements for “compliant” pipe bending:

1. Bend surface must be free of cracks [ASME B31.5 §529.1]
2. Bend surface must be free of buckles [ASME B31.5 §529.1]
3. The minimum thickness after bending must not be less than as required for straight pipe [ASME B31.5 §504.2.1]
4. Either hot or cold methods can be used to bend the pipe [ASME B31.5 §529.2]
5. If Heat Treatment is used, it must be performed in accordance with the requirements of ASME B31.5