What Does Pressure Test Mean?
A pressure test is used to determine the integrity of a pipeline after installation, before its commission and during its service life. This test is particularly useful in carrying out integrity assessments of pipelines carrying hazardous liquid or gas to prevent leaks or rupture under normal operating conditions.
There are two kinds of pressure testing; hydrostatic testing and pneumatic pressure testing.
Trenchlesspedia Explains Pressure Test
Pipelines are sometimes designed to withstand maximum operating pressure (MOP) such as those carrying natural gas and hazardous liquid. It must, therefore, be tested to ensure that the pipe is structurally sound and is capable of withstanding internal pressure from the product being carried.
In hydrostatic testing, the section to be tested is cleared of the product being carried and replaced with water. The pipe is then tested to at least 125% of MOP for 4 to 6-hours.
Pneumatic testing is done by using an inert gas such as nitrogen or air instead of water. Since compressed gas stores a greater amount of energy than compressed liquid, this test is used for pipelines that operate at pressures above 100 psig.
Gravity sewers are also pressure tested to ensure no leaks, damages or errors are made during laying of the pipeline.