+1 (806) 791-0567 •

Hydrostatic Re-Testing of Cylinders

Cylinder Hydrostatic Testing & Inspection

Are you in need of getting your  paintball, SCBA or SCUBA gas cylinder hydrostatic test current to stay compliant with U.S> Department of Transportation (DOT) regulations and be able to contine getting that cylinder filled? Texas Dive Center, inc. is a DOT registered and licensed agent authorized to conduct tests and re-certify a number of cylinders not exceeding 34" in length and 12' diameter, both steel and aluminum from 2000-10,000 PSI test range. We are the only scuba shop in the region that actually conducts the re-certification of these cylinders in-house and not ship them off somewhere to have someone else do it. We will show you our equipment, so ask those other dive shops to show you theirs and see their DOT certificate before leaving a tank with them.

WHAT IS A HYDRO TEST?

Hydrostatic testing is the most common way to check a cylinder for leaks or flaws.  During a hydrostatic test, the cylinder is examined by a Profefssional Scuba Inspector (PSI) to ensure it can safely hold its rated pressure. Cylinder hydrostatic testing is crucial as such containers can explode if they fail when containing compressed gase.

A hydrostatic test consists of first doing a visual inspection of the cylinder and valve for any signs of damage or corrosion. The cylinder is drained and the valve, stickers and other equipment removed. The cylinder internal surfaces are inspected and cleaned if required. Then the cyclinder is filled with water and placed in a special tank of water and pressurized to as much as 150% of it's rated service operating pressure and the displaced water from the expansion is measured to see if the cyclinder still falls withing DOT and manufacturer's tolerance levels. If the tank fails either the visual or the hydro test it is permanently taken out of service. Otherwise, the inspector re-certifies the tank.

All gas cyclinders require periodic hydrostatic testing as required by the U.S. Department of Transportation (DOT), who has regulatory oversight for cylinders in the U.S. The frequency of the maintenance depends upon the cylinder material. Contact us for more specific information on requirements for various cyclinders. Here are just a few:

  • Steel cylinders should be tested every five years and have a indefinite service life until they fail a hydro test or annual inspection.
  • Aluminum cylinders (not including hoop-wrapped) should be tested every five years and have an indefinite service life until they fail a hydro test or annual inspection.
  • Hoop-wrapped cylinders should be tested every three years and have a 15-year service life.
  • Fully wrapped fiberglass cylinders should be tested every three years and have a 15-year service life.
  • Fully wrapped Kevlar cylinders should be tested every three years and have a 15-year service life.
  • Fully wrapped carbon fiber cylinders should be tested every five years and have a 15-year service life.
  • Cylinders should not be filled if they have exceeded their useful service life or re-test dates.

 

 

 

 

Visual Inspection should also be performed on a regular basis (annual). This inspection should include, but is not limited to, removing the valve, inserting a high intensity light probe and angled mirror into the cyclinder and examining the inner surfaces of the cylinder. This inspection is necessary to aide in identifying defects in the inner surfaces of the neck and shoulder area of the cylinder. At Texas Dive Center Inc., we follw the protocols of the Professional Scuba Inspectors (PSI) as one of their Premier Facilities. Not all service providers replace the tank-oring or service the valve - but it should at least be inspected by a compentent technician and serviced or replaced if any doubt exists as to its safety, paying close attention to the burst disk, o-rings and any sign of abuse.

 

AVOID COMPRESSED GAS ACCIDENTS

Secure all cyclinders properly when transporting - ensure you protect the valves!

Do not leave them where heat can result in the internal pressure of the cylinder increasing.