To be eligible for recharging, how often must a DOT 3HT oxygen cylinder be hydrostatically tested?

For DOT 3HT oxygen cylinders, the requirement for hydrostatic testing is specified by the Department of Transportation regulations governing the transport and use of hazardous materials. Specifically, these cylinders must undergo hydrostatic testing every three years. This testing is crucial as it evaluates the integrity and safety of the cylinder, ensuring no leaks or failures that could occur from material fatigue or corrosion over time.

Maintaining this schedule is vital for safety compliance and operational reliability. While the other options suggest different intervals, the three-year testing cycle is established as the standard for this type of cylinder, reflecting the need for regular assessment while balancing safety and practicality for users.