In order to verify the structural integrity of pressurized systems such as; pipelines, plumbing, chemical pipelines, gas cylinders and fuel tanks, different types of testing can be performed. One of those varieties is called hydrostatic testing, which is a very effective method for finding leaks in these systems. This tester examines for leaks and measures the expansion under the tube, and determines its safety and reliability of the rating given. In a home environment, it helps plumbers to find leaks that have been caused by roots of trees seeking available water sources.
Hydrostatic testing involves filling the system with water, the key element to a hydro test, to a point greater than normally operated, and held as the component is examined. Water is commonly used because it is inexpensive and easily available, but also, it is usually harmless to the component being tested. At times, a colorant is added to the water to make detection of leaks more visible.
The testing pressure is held and monitored for a specific period of time, generally eight hours. It mimics the impact normally experienced inside the pipeline and, if defects are present, the water escapes, pinpointing the location of the leak. There are “spike tests” used where testing pressure is raised to beyond what is normal for a short period of time, usually about fifteen minutes.
The hydrostatic test is often used to examine equipment that was previously repaired or rebuilt in order to assure its quality before returning it to duty. The frequency of testing is varied, depending on the component. In most countries, there are requirements that must be followed. For instance, testing is required every two years for high pressure gas cylinders, with a visual inspection annually.
For low pressure cylinders, testing is required every five to ten years. More specifically, a DOT-3AL gas cylinder is required to have an unlimited life and must be tested every five years. The DOT-3HT gas cylinder requires a 24 year life and has to be tested every three years. While the DOT-3AA gas cylinder also needs an unlimited life, testing must be done every five years. Should the cylinder be marked with a “*”, that verifies it has met certain criteria, and can have a ten year hydrostatic test life. The guidelines for various types of pressure are normally specified by ISO, or the International Organization for Standardization, ASTM, the American Society for Testing Materials, or the ASME, American Society of Mechanical Engineers.
Hydrostatic testing is a very accurate way to test various pressure vessels for leaks. It is one of the most effective ways to test the integrity of stainless steel cylinders. It helps businesses take a proactive approach and prevent a disaster due to weak structure. Companies can avoid penalties for non-compliance, with cylinder testing certifications.
Further benefit is in the testing process itself, when the water pressure levels are increased to points higher than are normally the case under actual operation. The company is then armed with knowledge of the safety margin of the pipeline. The hydrostatic test identifies flaws, confirming the pipe strength and offers an ability to repair problems before the pipe is sent back to resume its normal duty.
In addition, the pressure testing is possible where alternative methods cannot be performed. Highly effective, accurate and reliable are all descriptions of the hydrostatic test. The benefits are many, and the security for present and future issues are set at a highly initiative level.