Pressure Testing to securing safety and stability

One of the foremost procedures employed to check for leaks in mechanical components, a pressure test is performed

One of the foremost procedures employed to check for leaks in mechanical components, a pressure test is performed to ascertain the safety, reliability, and insulation to leaks in a pressure system. Mechanical components that constitute a pressure system are either subjected to one of the many pressure tests either before they are used or after they have been repaired for a specific defect, or have undergone a structural alteration.

Across industries, particularly among those that involve use of heavy machinery or dangerous and volatile chemicals, pressure testing is of utmost importance since the safety of workers is at stake. For instance, a pipeline used for the supply of petroleum products is subjected to a pressure test, which, on the one hand, helps companies detect or ascertain the absence of leaks, while providing them with vital information on the extent of pressure that the pipeline can withstand. Equipped with this information, companies can better regulate the flow of the fluid or the gas in the pipelines.

Pressure tests are broadly classified into types

• Hydrostatic Tests
• Pneumatic Tests

How is a hydrostatic test conducted?

A time-tested method that is nigh indispensable to detection of leaks in industrial mechanical components, a hydrostatic pressure test is generally performed to assess the structural integrity of heavy machinery. Machine components often subjected to the hydrostatic pressure test are gas cylinders, boilers, and pipelines.

At a very rudimentary level, the hydrostatic pressure test is a verification procedure. It is performed to check if the vessel is capable of withstanding the amount of pressure that it has been certified to hold or resist. Hydrostatic pressure testing is a procedure that allows manufacturing companies to verify multiple parameters at once. Besides enabling firms to ascertain how much pressure or verifying if a component is capable of withstanding the volume of pressure for which it has been designed, the test will provide invaluable information on how stable the joints are, besides attesting to the strength of the material.

Generally depending on the component being tested and its function in the larger industrial set-up, a hydrostatic pressure test can anywhere between two and twelve hours. Throughout the duration of the procedure, it is imperative that the ambient conditions meet the criteria prescribed by the manufacturer. Detection of leaks in the component is possible only if the meters used for recording the pressure levels are being constantly monitored so that any variation in the pressure level within the component is instantly registered.

What is a pneumatic pressure test?

Pneumatic pressure tests are conducted with air and gases, all of which are non-inflammable and non-toxic such as nitrogen. However, the pneumatic pressure is not as commonly used as the hydrostatic pressure test. In fact, firms opt for the pneumatic pressure test only when the component or the system of which it is to be a part is designed such that it cannot be filled with water. The other reason why pneumatic tests are not conducted as widely is because the procedure involved is more hazardous since the conditions under which they are performed involve energy levels that are significantly higher compared to the hydrostatic pressure test.

However, the methodology used for conducting the pneumatic pressure test is similar to that of the hydrostatic pressure test insofar as the vessel or pipeline being tested for levels of pressure roughly 10% higher than that, which is specified as the maximum limit by the manufacturer of the component. Barring the delivery port or the output valve, the component being tested is completely sealed. One of the common methods used to conduct pneumatic test is the pressure decay leak test.

Today, the use of digital testing and recording devices has helped enhance the accuracy of pressure testing procedures. For instance, digital meters have helped eliminate the requirement of manual workers for tabulating the pressure levels. ing, and using smart sensors to further boost the accuracy and efficacy of pressure testing procedures.