Hydrostatic (Hydro) Testing is a process where components such as piping systems, gas cylinders, boilers, and pressure vessels are tested for strength and leaks. Hydrostatic tests are often required after shutdowns and repairs in order to validate that equipment will operate under desired conditions once returned to service.
Want more information on hydrostatic test machine? Feel free to contact us.
Furthermore, hydrostatic testing cannot be performed during normal operations and cannot monitor equipment for leaks after the test has been performed. On-stream equipment integrity is best managed by an effective fixed equipment mechanical integrity program.
Although hydrostatic testing is considered to be a nondestructive testing method, equipment can rupture and fail if the inspection exceeds a specified test pressure or if a small crack propagates rapidly.
Hydrostatic testing is a type of pressure test that works by completely filling the component with water, removing the air contained within the unit, and pressurizing the system up to 1.5 times the design pressure limit the of the unit. The pressure is then held for a specific amount of time to visually inspect the system for leaks. Visual inspection can be enhanced by applying either tracer or fluorescent dyes to the liquid to determine where cracks and leaks are originating.
There are three common hydrostatic testing techniques that are used to test small pressure vessels and cylinders: the water jacket method, the direct expansion method, and the proof pressure testing method.
In order to conduct a this method, the the vessel is filled with water and loaded it into a sealed chamber (called the test jacket) which is also filled with water. The vessel is then pressurized inside the test jacket for a specified amount of time. This causes the vessel to expand within the test jacket, which results in water being forced out into a glass tube that measures the total expansion. Once the total expansion is recorded, the vessel is depressurized and shrinks to its approximate original size. As the vessel deflates, water flows back into the test jacket.
Sometimes, the vessel does not return to its original size. This second size value is called permanent expansion. The difference between the total expansion and permanent expansion determines whether or not the vessel is fit-for service. Typically the higher the percent expansion, the more likely the vessel will be decommissioned.
The direct expansion method involves filling a vessel or cylinder with a specified amount of water, pressurizing the system, and measuring the amount of water that is expelled once the pressure is released. The permanent expansion and the total expansion values are determined by recording the amount of water forced into the vessel, the test pressure, and amount of water expelled from the vessel.
The proof pressure test applies an internal pressure and determine if the vessel contains any leaks or other weakness such as wall thinning that may result in failure. In the United States, this method is only permitted when the U.S. Code of Federal Regulations does not require permanent and total expansion values to be recorded.
Some equipment may not be designed to handle the loads required for a pressure test. In these cases, alternative methods such as pneumatic testing should be employed. Pneumatic testing is another type of pressure test that involves pressurizing the vessel with a gas such as air or nitrogen instead of water. However, special caution should be used when performing pneumatic testing as gaseous mediums have the ability to be compressed and contained in larger amounts compared to hydrostatic testing.
For pipelines, hydro tests are conducted while the pipeline is out of service. All oil and/or natural gas is typically vented off, and the line is mechanically cleaned prior to testing.
In any case, operators and inspectors should consider the properties of the hydrotest fluid medium and how the medium may have an effect on the equipment. For example, water is a good environment for corrosion to take place. Therefore, equipment should be properly dried and contaminant free before starting operations.
We welcome updates to this Integripedia definition from the Inspectioneering community. Click the link below to submit any recommended changes for Inspectioneering's team of editors to review.
Contribute to DefinitionWhat You Need to Know About DOT Hydrostatic Testing Requirements for Low Pressure Cylinders
Hydrostatic testing is one of the most effective ways to test the structural integrity of stainless steel cylinders. Successful hydrostatic testing of low pressure cylinders can help businesses to effectively prevent potential disasters that may occur due to use of structurally weak cylinders. In addition, companies can avoid penalties from DOT for not complying with cylinder testing certifications. The Department of Transportation employs strict guidelines for any business which transports low-pressure stainless steel cylinders containing compressed gas and other chemical materials. These guidelines are set forth by DOT Pipeline and Hazardous Materials Safety Administration (PHMSA), and in accordance with the Compressed Gas Association (CGA).
If you are looking for more details, kindly visit china hydro testing machine suppliers.
DOT Specifications
DOT specifications are designed to regulate the strength and quality of stainless steel cylinders. The DOT specifications require stainless steel cylinders are tested every 3, 5, 10, or in exceptional cases, 12 years. The frequency with which a cylinder must be tested depends upon the age of a cylinder, the type of gas or chemicals it contains, the particular material of the cylinder, and its OEM rating.
If a cylinder is designated for a specific pressure limit, and it is determined that the cylinder is not equipped to handle that pressure, then the cylinder cannot be certified for use. These guidelines are designed to help prevent unnecessary disasters that may occur due to the transporting of faulty cylinders, and therefore it is crucial to understand and comply with these regulations at times. Since 2009, PHMSA oversight programs have helped to decrease serious incidents associated with catastrophic failure of cylinders by 39%.
Markings and Pressure Limits
DOT controlled cylinders are required to be marked with a specific rating, and each required marking must be maintained so that it is clearly legible at all times. When a cylinder is retested or rebuilt, the marking must be updated as necessary to continue to meet this requirement.
DOT Testing Certification
In order to maintain DOT compliance, all DOT regulated cylinders must be periodically tested by a certified DOT testing facility. The testing facility should be equipped to test, inspect, certify, repair and/or rebuild low-pressure stainless-steel cylinders according to the appropriate methods for hydrostatic testing.
The DOT hydrostatic testing facility must meet the requirements of 49 CFR Sections 107.805, 180.211, and 180.212 to be approved to inspect, test, certify, repair, or rebuild a cylinder in accordance with a DOT specification. A facility may be certified for testing one or more ratings of cylinders. Therefore, it’s important to research any businesses offering DOT cylinder testing services, to ensure that they are certified to test to the particular cylinders that are being transported.
Jay L Harman Fire Equipment is certified and qualified to test, inspect, and certify low-pressure stainless-steel cylinders. We use a state of the art hydrostatic tester to perform re-qualification testing. Cylinders are inspected for leaks, and the integrity of each unit is confirmed. If you have low-pressure canisters that require certification or recertification, please contact us to discuss your specific needs.
The Jay L Harman Fire Equipment team understands your firefighting needs and is ready to help
Jay L Harman’s DOT Hydrostatic Testing facility and equipment meet all NFPA requirements for the hydrostatic testing of self contained breathing apparatus compressed gas cylinders in addition to testing ABC portable fire extinguisher cylinders.
Jay L Harman is the best and one of the biggest firefighting equipment suppliers and service providers in the region, specializing in fire suppression systems, fire extinguishers, emergency lighting, fire hoses, hydrostatic testing and more. Serving El Paso TX, Las Cruces NM and the surrounding areas, we pride ourselves on buying local and hiring local whenever possible.
Jay L Harman Fire Equipment is your go-to distributor for OVAL low-profile fire extinguishers in West Texas and New Mexico.
Contact Jay L. Harman Fire Equipment in El Paso TX at 915-533-7021 or Las Cruces NM at 575-523-8880.
Since 1925, we have protected businesses throughout the area from the harms and hazards of fires. Every Jay L Harman technician is licensed and regulated by the Texas Department of Insurance State Fire Marshal’s Office. Each of these technicians continually receives the most up-to-date factory training and certifications by our manufacturers. Contact Jay L Harman Fire Equipment today. Let our friendly and knowledgeable staff tell you more about our fire suppression systems and help you find the ideal fire suppression system for your needs. Learn more about our full offering of fire extinguisher training, firefighting services, firefighting products, request a quote, ask a question or request additional information.
For more information, please visit air boosters.