Do insert flanges conform to the requirements of ASME B31.3?
The answer to this question is YES. Process Piping, ASME B31.3, provides guidelines for the design of flanges which are not included as standards in Table 326.1 of this specification. These requirements are found in paragraph 304.5.1 of the code. This specifically says, “flanges may be designed in accordance with the Boiler Pressure Vessel Code, Section VIII, Div 1, Appendix 2 or Appendix Y, depending on whether the gasket OD is inside or outside the bolt circle. Flanges may be qualified by the requirements of paragraph 304.7.2. This paragraph applies when Appendix 2 or Appendix Y are not applicable and states that the design is to be based on calculations consistent with the design criteria on B31.