ASME B31压力管道规范和ASME 锅炉和压力容器规范，第三节，核 部件、NC和ND小节管道规则 要求使用应力强化因子（SIF或 i-系数）和灵活性系数（k-系数） 部件和接头（焊接和焊接）的充分性 非焊接）在承受各种载荷的管道中，包括 可能导致疲劳失效的循环载荷。

The ASME B31 Code for Pressure Piping and the ASME Boiler and Pressure Vessel Code, Section III, Nuclear Components, Subsections NC and ND piping rules require the use of stress intensification factors (SIFs or i-factors) and flexibility factors (k-factors) when checking the adequacy of components and joints (welded and nonwelded) in piping subject to various loads, including cyclic loads, that may produce fatigue failures.