Full-Scale Burst Tests With Hydrogen

Abstract Five full-scale burst tests in hydrogen and four in water have been conducted on nominally identical pairs of vessels containing nominally identical defects to investigate the effect of hydrogen on the burst strength of defects in pipelines. A short section of line pipe cut from a pipeline commissioned in 1969 was used to fabricate the test vessels. The line pipe has a nominal diameter equal to 609.6 mm (24 in.) and a nominal wall thickness equal to 11.91 mm. It is Grade X52. It has a longitudinal seam weld. Five different types of defects were tested in the burst tests: an internal and external, sharp, part-through-wall defect (the internal defect was only tested in hydrogen); an external, blunt part-through-wall defect; a plain dent; and a dent and gouge (a notch). The part-through-wall defects were longitudinally orientated. The defects were all in the pipe body. The blunt and sharp, part-through-wall defects had nominally identical depths and lengths. The failure pressures of the external, blunt and sharp, part-through-wall defects, plain dents and smooth dents and gouges (notches) in hydrogen and in water were similar. The failure pressures of the internal, sharp, part-through-wall defect in hydrogen was significantly lower than that of the external defect in hydrogen and in water.