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Hydrostatic Testing for Stainless Equipment

We hydrostatically test stainless pressure vessels, jackets and pipework in our workshop before they leave, and retest repaired or modified equipment before it goes back into service.

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Hydrostatic Testing for Stainless Equipment

ASSDA accreditedSince 1996 · built in Brisbane, delivered Australia-wide

How a Hydrostatic Test Works

A hydrostatic test proves that a vessel, jacket or pipe system can hold pressure. The equipment is filled with water, the air is vented out, and the pressure is raised to a test pressure above the pressure it will run at. It is held there while every weld, joint, nozzle and fitting is checked for leaks and distortion.

Water is used because it barely compresses. At the same pressure it stores far less energy than air or gas, so if a weld does fail under test it leaks rather than bursts. That is why a hydrostatic test is normally preferred over a pneumatic (air) test for pressure equipment.

Shows welds and joints hold at test pressure
Finds leaks at nozzles, flanges and fittings
Shows up distortion before the equipment is in service
Gives you a test record for your files

What We Hydrostatically Test

We do hydrostatic testing in house, depending on the size of the tank, in our stainless-only workshop in Murarrie, Queensland, for customers across Australia.

New Pressure Vessels

Every pressure vessel we build is pressure tested in our workshop before delivery, by hydrostatic or air test.

Heating and Cooling Jackets

Jackets are pressure tested so a leak shows up in the workshop, not in your product.

Pipework

Process pipework we fabricate is pressure tested before it leaves.

Repaired and Modified Equipment

After a weld repair, a new nozzle or a new jacket in our workshop, we test the work before the equipment returns to service.

Atmospheric Tanks

Tanks that do not run under pressure can be fill tested with water before handover. Whether a fill test suits depends on the tank’s size and design and on your requirements.

When Equipment Needs a Hydrostatic Test

A new pressure vessel is pressure tested before it goes into service. The design standard the vessel is built to sets the test, and for our pressure vessels that is AS 1210. Jackets and pressure pipework are tested for the same reason: the first time they see pressure should be in a controlled test, not on your plant.

A test is also usually needed after work on a pressure part. A weld repair, a new nozzle, a cut-in manway or a new jacket all change the equipment, so the work is tested before it goes back into production. Your pressure equipment inspector or regulator may also call for a pressure test after an in-service inspection if the findings warrant it.

If you are not sure whether your tank counts as a pressure vessel, send us its operating pressure and temperature and we will tell you what applies.

How We Run a Hydrostatic Test

01
Set the Test
The design pressure is confirmed on the approval drawing. The test pressure and hold time come from the design standard and are agreed before the test.
02
Prepare and Fill
Openings are blanked, the equipment is filled with water and the air is vented out so the test is safe and the reading is true.
03
Pressurise and Inspect
Pressure is raised to the test pressure and held while we inspect every weld, joint and fitting for leaks and distortion.
04
Drain, Dry and Record
The equipment is drained and dried, and the result is recorded for your handover documents.

Test Water for Stainless Steel

Stainless steel resists corrosion well, but chlorides in water left standing in a vessel can start pitting and crevice corrosion, especially at welds and crevices. A hydrostatic test that leaves dirty or salty water sitting in a new vessel can damage the finish.

Because we work only in stainless, we treat the test water as part of the job. We use potable council water where possible, and truck in spring or demineralised water when your specification calls for it. Once the test has been witnessed and signed off, the vessel is drained and air dried.

What You Receive

Tell us at quote stage what your site, inspector or regulator needs, and we will confirm it in the quote.

Approval drawing	Shows the design pressure for the vessel or jacket
Hydrostatic test record	Test pressure, hold time, result and sign-off
Weld inspection	Dye penetrant results from testing in our workshop, and radiography results arranged through a NATA-accredited third party where the design calls for them, included in your MDR
Manufacturer's data report	Every new tank or vessel we build comes with an MDR, including material certificates, welding procedures and qualifications (WPS/PQR) and NDT records
Third-party certification	Design verified by a third-party RPEQ (Registered Professional Engineer of Queensland) for our AS 1210 pressure vessels
Witnessed test	You or your inspector are welcome to witness the test at our workshop. Independent witnessing of fabrication and testing can be arranged through our third-party engineers.
Where	In our Murarrie workshop. We do not test on site.

Questions About Hydrostatic Testing

For anything else, call (07) 3348 9444.

What is hydrostatic testing?

It is a pressure test using water. The vessel, jacket or pipework is filled with water and raised to a test pressure above its operating pressure, then held while welds and joints are checked for leaks and distortion.

What is the difference between a hydrostatic and a pneumatic test?

A hydrostatic test uses water and a pneumatic test uses air or gas. Water barely compresses, so it stores much less energy at the same pressure and a failure leaks rather than bursts. That makes hydrostatic testing the usual choice for pressure equipment. We do both hydrostatic and air testing in our workshop.

Is every pressure vessel you build pressure tested?

Yes. Every pressure vessel we build is pressure tested in our workshop before delivery, by hydrostatic or air test; hydrostatic testing in house depends on the size of the vessel. We carry out dye penetrant testing of the welds in our workshop, and where the design calls for it, radiography is arranged through a NATA-accredited third party. Any other testing your specification calls for (for example borescope inspection, riboflavin coverage testing, surface finish (profilometer) checks and material verification) can be arranged through NATA-accredited third-party testers, and the results go into the vessel's MDR.

What test pressure will you use?

It depends on the design pressure and the standard the equipment is built to. We confirm the test pressure before the test and record it.

Can the test be done on our site?

No. Our hydrostatic and air testing is done in our Murarrie workshop, where the equipment, water supply and drainage are set up for it. We hydrostatically and air test vessels and complete a pre-delivery inspection before anything leaves.

What water do you use for the test?

Potable council water where possible. If your specification calls for spring or demineralised water, we truck it in. The vessel is drained and air dried once the test has been witnessed and signed off.

Do you fill test atmospheric tanks?

It depends on the tank's size and design and on your requirements. We agree it with you at quote stage.

Can our inspector witness the test?

Yes. You or your inspector are welcome to witness the test at our workshop. Independent witnessing of fabrication and testing can be arranged through our third-party engineers. Tell us at quote stage so we can plan the date.