I have written a lot about the hazards of “pressure testing” piping, and in all of those posts I have stated how much “safer” Hydrostatic Testing is, compared to pneumatic testing. But this fatal accident shows us that even hydrostatic testing comes with fatal risks.
During a hydrostatic pressure test of a fire suppression system, a subcontracting pipefitter, 49, was struck by a 64-inch-long, 12-inch-diameter vertical section of a pressurized PVC pipe. The pipe thrust upward approximately ten inches toward the decedent’s chest, striking the impact driver he was using to tighten flange bolts on the end cap of the pipe. The pipe came loose under pressure because the torque shear bolts on the mechanical joint restraining gland had not been tightened at all. The gland connected the vertical pipe to the flange of a horizontal pipe running parallel to ground level, about 4 feet deep. The pipefitter was knocked backward and fell onto a rebar grid surrounding the pipe.