When do you need a sensitive leak test?
A sensitive leak test is a required part of an alternative leak test code requirements. This test is performed at low pressures to test for leaks. This test is performed at low pressures to test for leaks.
How long does a leak test need to be maintained?
A leak test must be maintained for a minimum of 10 minutes or the length of time that it takes to visually inspect each pipe weld and mechanical connection for leaks. An alternate leak test is allowed, with the owner’s approval, when neither a hydrostatic nor a pneumatic leak test would be possible or safe.
When to use an alternative leak test for a hydrostatic leak test?
An alternate leak test is allowed, with the owner’s approval, when neither a hydrostatic nor a pneumatic leak test would be possible or safe. An alternative leak test contains the following required elements:
When to do a leak test on a piping system?
Piping design codes all require a leak test prior to a system being placed into service. Leak testing is usually conducted at pressure levels at or below the system operating pressure. A leak test as prescribed by design codes is performed at a factor times the design pressure of the piping system.
How can errors be identified in leak testing?
Sometimes, errors in a test setup can be identified by regularly checking the accuracy of the system by using a reference leak that, due to its defined size, is always the same leak rate. If this leak rate is not determined during the test, the system has inaccuracies.
Is it necessary to evacuate part of leak test?
Some tests are performed with a helium content of only 1 percent—which means that the proper distribution of the tracer gas is even more important. For proper leak testing it is absolutely mandatory to evacuate the test part before filling it with tracer gas. This is particularly important for long and narrow geometries.
How is a gross leak detected in a vacuum test?
In a gross leak the helium escapes from the test piece before the actual test interval. In effect, you evacuate the vacuum test chamber and the helium from the test piece at the same time. Sometimes a simple pressure decay test is integrated into the tracer gas system to identify any gross leaks before filling the test piece with helium.
How does the leak rate of an integral leak test work?
Also consider that the leak rate of an integral leak test and subsequent leak detection have to work together. Sometimes the integral leak test is carried out in a helium chamber, but the subsequent localization of leaks is carried out using the bubble test method instead of using a more precise sniffer leak detection method with tracer gas.