Establishing Fracture Mechanics Based on Minimum Allowable Temperature for Low-Temp Applications of ASME B31.3

E²G | The Equity Engineering Group, Inc. has performed numerous brittle fracture studies involving single pieces of equipment and entire units that are at risk of brittle fracture.  Brittle fracture studies of piping systems do not have the same simplified approach to brittle fracture due to the concern that longitudinal piping loads may govern the minimum allowable temperature (MAT) assessment.  In the past, the ASME B31.3 procedure has required the execution of a piping flexibility analysis to quantify the longitudinal stress.  Additionally, the ASME B31.3 minimum design metal temperature (MDMT) method does not have any benefit for post-weld heat treatment (PWHT), which we know from fracture mechanics is a large contributor to an acceptable flaw size.