5.5.4 Flanged Joints
Flanges of all types (see 4-6-2/Table 6 for typical types) conforming to and marked in accordance with a recognized national standard may be used within the pressure-temperature ratings of the standard, subject to limitations indicated in 4-6-2/Table 7. For flanges not conforming to a recognized standard, calculations made to a recognized method are to be submitted for review. Non-standard flanges are to be subjected to the same limitations indicated in 4-6-2/Table 7. Flanges conforming to a standard are to be attached to pipes by welding or other acceptable means as specified in the standard. Non-standard flanges are to be attached to pipes by a method approved with the design.