When to Hydro Test SCUBA Tanks

Scuba tanks and all pressurized cylinders must be regularly checked to ensure the cylinder can safely be used and not explode or leak. Because scuba tanks hold air for breathing underwater, proper maintenance includes an annual internal inspection and pressurized testing every five years. Hydrostatic testing (also known as hydro testing) involves pressure testing the tank cylinder for weaknesses in the structural integrity. All inspections must be current before tanks can be filled safely.

  1. Significance

    • Pressurized scuba cylinders must undergo an annual visual inspection and regular hydrostatic testing. The U.S. Department of Transportation (DOT) has licensed facilities and specific regulations for hydrostatic testing of high-pressure cylinders.

    Time Frame

    • Scuba tanks must be thoroughly visually inspected (VTI) to ensure the inside of the cylinder is free from corrosion and internal particles. Hydrostatic testing is required every five years to ensure the tank is structurally sound when filled with pressurized air.

    Process

    • For hydrostatic testing, the tank is filled with water, sealed and subjected to a greater pressure than the tank's PSI rating. Water is used to detect any leaks or weaknesses in the tank, and the cylinder resiliency to revert to its original size is measured.

    Identification

    • Tanks are imprinted with hydrostatic information, which is located after the serial number of the tank and before its rated pressure.

    Benefits

    • Scuba tanks that are current in visualization and hydrostatic testing indicate the tanks are safe to fill and to use underwater. The tank chamber will provide clean air and the cylinder does not have any weaknesses.

    Considerations

    • Scuba tanks are generally useful for 100,000 air fills with proper maintenance. Steel tanks are more durable than aluminum tanks because the material is more resilient to withstand pressure.