Hydrostatic Testing

Hydrostatic Testing: What is it, how does it work, and what are the benefits?

Hydrostatic Testing: What is it, how does it work, and what are the benefits?

Hydrostatic testing can be defined as the process of subjecting a material to a controlled pressure and observing how it reacts to the pressure. The test is used for many reasons: determining if an object will withstand various loads or stresses, detecting leaks in hydraulic systems or pipes, ensuring that equipment functions properly before use, etc. Hydrostatic tests are conducted by filling an object with water and pressurizing it until there’s no more give left in its structure–at which point the air bubbles stop coming out. The ability to detect leaks in an object is one of the most important reasons why this type of testing should be performed regularly.

This article will discuss what hydrostatic testing entails, how it works, and the benefits associated with it.

What is hydrostatic testing?

 Hydrostatic testing is an integral part of quality control. Hydrostatic tests are performed to determine the structural integrity and fitness for use of a variety of objects including gas cylinders, storage tanks, and chemical pipelines. The test works by filling the object with water until it’s completely full and then pressurized–ensuring that it can hold up under pressure without bursting open at any seams nor allowing air bubbles to escape from within its structure.

The name comes from when engineers used compressed air as their hydraulic fluid instead of water; the term “hydro” meaning water in Greek) and “statikos,” which means solid (as in static).

Hydrostatic testing also provides a level of confidence that the object will hold up under pressure and withstand exposure to corrosive environments without bursting open at any seams nor allowing air bubbles to escape from within its structure.

What is hydrostatic testing used for?

Hydrostatic testing is a pressure-based technique used to test the integrity of piping systems, gas cylinders, boiler components, and all other kinds of pressure vessels. Hydro-tests are commonly done after repairs and downtime to determine if items will operate properly when put back into use.

Hydrostatic testing is a common tool used by engineers to ensure that equipment has been rebuilt or repaired properly. It’s most commonly employed for DOT-required stainless-steel canisters with the aim to work out any potential leaks and verify it is fully safe for use. This is important because if you have a DOT-required container and it’s not been properly tested, what is inside the canister could be contaminated.

A hydrostatic test will bring up any potential leaks in equipment and also show if there are any structural problems with the exterior or interior of the tank that might lead to leaks later on.

How does hydrostatic testing work?

Hydrostatic testing is done by filling containers with water at high pressure until they reach their designated capacity; this allows engineers to see where air bubbles appear (signifying small holes) as well as find out how strong each welded seam really is. This type of inspection provides much more information than just visually inspecting your stainless-steel canisters because you’re looking for inconsistencies and then repairing them before something goes wrong during use.

Hydrostatic testing to 60,000PSI is an effective method for detecting a leak before it becomes costly. Hydrostatic tests can also be used in conjunction with other seals testing methods such as CGA, which is very useful when performing diagnostics on machines with many different types of seals – hydrostatic has the ability to identify and isolate faulty sections of rubber or metal sealant that might have been overlooked by another test.

The process works because water will breach any gap between two pieces of imperfectly sealed pipe if there’s enough pressure applied to force its way through; this means every time we turn on our faucet and allow water into the pipes below ground, those leaks are being detected without us ever knowing about them.


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What are common hydrostatic testing requirements?

The three common hydrostatic testing techniques are CGA, DOT and ISO 14644-12. CGA is the most common of these methods, followed by DOT and then ISO 14644-12.

  • CGA tests are quick and easy to perform making them an ideal choice for small repairs such as oil leaks or hoses that need inspection before they can be used again.
  • DOT testing involves a more thorough evaluation, but it does not require any special tools other than those available at your local gas station which makes it both cost effective and convenient considering you probably already have the equipment handy in case of emergencies! ISO 14644 12 on the other hand requires expensive machines to complete successfully so if this test method isn’t required by law there’s no reason you should use it.

Maintaining your CGA certification proves to be a cost-effective way of ensuring that you are driving at peak efficiency by helping determine any leaks or other problems before they become a danger. Hydrostatic testing will help identify seals that may have been compromised during installation, which means no more having to guess when something goes wrong! DOT tests on the other hand can provide an inexpensive alternative for those looking for confirmation in cases where hydrostatic testing isn’t required as well as being beneficial because there’s no need to purchase expensive machinery like with ISO 14644 12.

  • ISO 14644-12 has its place but sometimes is unnecessary – if this is the case, then DOT testing is a cost-effective alternative. ISO 14644-12 involves running a machine with an in-line leak detector and pressure sensors that will tell you the quality of your seals.

Meeting DOT Specifications for hydrostatic testing

Sometimes, hydrostatic testing is required for vehicles with a gross vehicle weight of more than 26000 pounds. Hydrostatic testing is also mandated by the Department of Transportation (DOT) as part of the certification process to show that a cargo tank and its fittings are able to maintain an airtight seal under pressure when being filled or emptied. This ensures that they do not leak any flammable fluids during their use. The DOT’s rules mandate this test before each new filling or emptying event in order to prevent catastrophic damage in case there was a puncture somewhere along the way.

How do I avoid disasters with hydrostatic testing?

The best way to avoid disaster is to have an experienced technician perform your hydrostatic testing. There are two main types of tests:

  • Type I, which is conducted at the completion of construction and includes a tank test for pressure integrity as well as confirmation that all welds are intact
  • Type II, which evaluates specific components like tanks or pumps used in underground storage systems

Just because you’ve done this type of testing before doesn’t mean it’s time to stop! Hydrostatic testing should be performed every year after installation or sooner if there has been any change in environmental conditions.

What are the benefits with outsourcing hydrostatic testing?

Working with a company that offers hydrostatic testing services can be more beneficial than purchasing and operating the equipment because of cost, time, and resources. Additional benefits include a faster turnaround time, increased safety for your staff and customers resulting in improved product quality assurance; decreased repair costs; minimizing risk exposure and liability claims.

A team highly trained hydro-testers can help chemical, industrial or other companies to stay compliant with DOT specifications.


Hydrostatic testing provides many benefits for a business by ensuring the quality of their product. For example, this process can be used to ensure that equipment is functioning properly before use and also detect leaks in hydraulic systems or pipes. If you are interested in learning more about hydrostatic testing and other methods we offer, or if you need help meeting DOT or CGA specifications, it may be time to outsource the process with an experienced partner like us here at Precision Fabricating & Cleaning. Contact us today!


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