Abstract:
To ensure that the high strength pressure test of gas pipeline test section with 0.8 design coefficient in China has adequate safety allowance, three aspects are analyzed, namely, the relationship between hoop strain and the nonlinear deflection quantity of testing pressure-volume curve, the allowable value in the existing standards for pipeline radial expansion amount after the pressure test, and the cause of pressure reversal. Then, three eligibility criteria of high strength pressure test are proposed, that is, ① in order to avoid wide range of yielding in the pipeline, the nonlinear deflection quantity of testing pressure-volume curve is no more than 0.2% under normal circumstances and no more than 0.4% under special circumstances, ② in order to avoid serious plastic local deformation, the pipeline radial expansion ratio should not exceed 1.7% after pressure testing and ③ in order to make the pipeline have higher reliability, NDT of can be conducted to rule out the pipeline defects that are more than the critical size. The first two are compulsory standards, while the last one is a voluntary standard.