What is a hydrostatic test?
A hydrostatic test is a water pressure test that confirms the structural integrity of the pipeline. During the test, the fuel in the pipeline is displaced with water and the pressure is raised to 125% of the maximum operating pressure for four hours. Then it is held for another four hours at 110% of maximum operating pressure. The pressure in the pipeline is continuously monitored during the test to insure that it does not drop. If the pressure stays the same throughout the eight hours, the test is considered successful. A drop in pressure indicates a possible leak in the line. Hydrostatic tests have been done for over 40 years on pipes and have been performed on portions of the Olympic pipeline in Woodinville, Bellingham, Renton, Bellevue and Redmond.
