Abstract:  Controlling the assembly bolt load and determining the maximum bolt seating stress is an effective solution to the flange joint leakage. Based on the WRC Bulletin 538, this paper introduces an evaluation method of the flange assembly, so as to determine the flange loaded capacity. Through examples, it is verified that the standard pipe flange has some loaded capacity allowance, which provides a vital basis for determining the maximum bolt seating stress and ensuring the overall tightness of the flange joint.

Key words: pipe flange, erection stress, loaded capacity