In addition to the requirement that cylinders be visually inspected at least once a year, the Department of Transportation (DOT) mandates tanks be hydrostatically tested (hydro’d) at least once every five years. For some types of cylinders, the hydro test interval is even less.
The hydro test process involves:
- Filling a cylinder with fresh water, then immersing it in a water-filled jacket capable of handling pressures far beyond the rated working pressure of the tank.
- Pressurizing the test cylinder — typically to five-thirds its rated pressure. This causes a microscopic flex in the cylinder’s wall.
- The momentary over-pressurization of the test cylinder then displaces some of the water in the outer jacket. The system then collects and measures the displaced water. If the amount is within tolerances, the tank passes. Otherwise, it’s condemned.
Scuba Tank Services can conduct hydrostatically test cylinders from a wide variety of sizes and uses, including:
Our equipment can test cylinders with working pressures up to 7,500 psi. All tests are conducted by DOT-certified technicians.
Standard turnaround time for hydrostatic testing is 72 hours — but most of our customers get their tanks back within 24 hours. Rush service is available.
Visit our price list page for costs.