Pressure testing or hydrostatic testing is the test which is carried out after the installation of any pipeline before it is put into use. The purpose of the pressure testing is to investigate the various limits of the pipeline which will test areas such as the reliability, maximum capacity, leaks, joint fittings and pressure. Without this information the pipe can not be put into service and the owner/operators have no knowledge if the pipe meets the set requirements.
The information found from pressure testing aids to maintain the safety standards and the upkeep of the pipeline. When there is a new manufactured piece of equipment the pipelines are initially qualified by using a pressure test/hydrostatic test and regularly re-qualified at different intervals, which is called, the “modified hydrostatic test” or “proof pressure test”.
When testing pipelines they are conducted under the industry’s or customer’s specifications, filling the vessel with an incompressible liquid, like water or oil. This examines the pipe for any leaks or changes in shape. Generally dyes are added to the water in order to detect leaks with ease. When pressure testing, the amount of pressure put onto the vessel is always considerably more than the normal operating pressure. This is to allow for any unexpected pressure levels on the vessel for maximum safety.
Information for the tester are stamped onto the vessel, this may include serial number, manufacturer and manufacturer date. There may be other information such as, REE (Rejection Elastic Expansion) and maximum expansion specified by the manufacturer for safety. This information is usually recorded on a computer system which will allow the owner to keep track when the tests have taken place or need to be scheduled in.
