Pipelines and other similar units have to be occasionally tested to see if there are existing or possible leaks and if their performance is still adequate. Hydro testing is usually required by authorities after different repairs, but it has to be performed in regular intervals just to check if everything is working properly. Similar testing is used for pressure vessels and other pressure units.
This testing is performed when the whole system is shut down, and cannot be done when it is running. The test is nondestructive testing method and it might be necessary to be performed before different licenses for normal operating can be issued. The whole unit has to be checked for leaks and other problems that could be the cause of failure.
When it comes to different pipelines, the system should be first totally emptied, and all natural gas, oil or other substances removed. After that, the pipeline should be mechanically cleaned and vented. The whole system is then filled with water, and this process removes all the remains of air held within. After that, the pressure that exceeds the designed pressure limit of this pipeline is applied.
I average, the pressure used is fifty percent higher than the pressure thee pipes are designed for. This is to determine the system strength, as well to make it easier to find leaks and other damages. The pressure should remain until this system is visually checked by personnel, and it is also possible to use fluorescent dyes to find leaks and their origins, as well as cracks.
After the process is finished, the pipes should be cleaned and dried before you can refill them with the medium they were designed to carry. The person applying the test has to take into consideration the differences between the fluids and how their different properties may affect the entire system.
Small vessels, cylinders and similar equipment and units are tested using different methods. There are three main types that are used, and some are more applicable for particular purposes. Direct expansion method is normally used for testing the pressure vessels. In this process, the vessel should be filled with water, and then the pressure is applied, for designated amount of time. Resulting expelled water is measured for testing results.
The second method is similar, but the vessel filled with water is first loaded into a sealed chamber, so called test jacked. This is why this method is called water jacket method. While in the sealed chamber, the vessel is pressurized. The applied pressure forces some amount of water out from the chamber, and the water that is expelled is measured to find out total expansion.
When this process is over, the vessel should shrink to its original size. If it doesn't shrink back totally, the difference between sizes will tell you if the vessel needs the service. The pressure method is used in cases when measuring this difference is not so important, or required by various laws. In this case, the unit is only checked for leaks or wall thinning that may be causes of failure.
This testing is performed when the whole system is shut down, and cannot be done when it is running. The test is nondestructive testing method and it might be necessary to be performed before different licenses for normal operating can be issued. The whole unit has to be checked for leaks and other problems that could be the cause of failure.
When it comes to different pipelines, the system should be first totally emptied, and all natural gas, oil or other substances removed. After that, the pipeline should be mechanically cleaned and vented. The whole system is then filled with water, and this process removes all the remains of air held within. After that, the pressure that exceeds the designed pressure limit of this pipeline is applied.
I average, the pressure used is fifty percent higher than the pressure thee pipes are designed for. This is to determine the system strength, as well to make it easier to find leaks and other damages. The pressure should remain until this system is visually checked by personnel, and it is also possible to use fluorescent dyes to find leaks and their origins, as well as cracks.
After the process is finished, the pipes should be cleaned and dried before you can refill them with the medium they were designed to carry. The person applying the test has to take into consideration the differences between the fluids and how their different properties may affect the entire system.
Small vessels, cylinders and similar equipment and units are tested using different methods. There are three main types that are used, and some are more applicable for particular purposes. Direct expansion method is normally used for testing the pressure vessels. In this process, the vessel should be filled with water, and then the pressure is applied, for designated amount of time. Resulting expelled water is measured for testing results.
The second method is similar, but the vessel filled with water is first loaded into a sealed chamber, so called test jacked. This is why this method is called water jacket method. While in the sealed chamber, the vessel is pressurized. The applied pressure forces some amount of water out from the chamber, and the water that is expelled is measured to find out total expansion.
When this process is over, the vessel should shrink to its original size. If it doesn't shrink back totally, the difference between sizes will tell you if the vessel needs the service. The pressure method is used in cases when measuring this difference is not so important, or required by various laws. In this case, the unit is only checked for leaks or wall thinning that may be causes of failure.
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