If a high-pressure cylinder has been discharged, what is the requirement for hydrotesting?

Hydrotesting, or hydrostatic testing, is a critical procedure for ensuring the integrity and safety of high-pressure cylinders, particularly after they have been discharged. When a high-pressure cylinder has been discharged, it must be evaluated for structural integrity before being put back into service.

The requirement that it should be hydrotested if more than five years have elapsed aligns with industry standards and regulations regarding the testing of pressure vessels. This timeframe serves as a guideline for maintaining safety and verifying that the cylinder has not developed any defects or weaknesses during its service life. If this period exceeds five years without testing, the risk of failure or malfunction increases due to factors like material fatigue, corrosion, or environmental influences.

In contrast, recharging a cylinder immediately without hydrotesting would be unsafe, as there may be unseen issues that could lead to a catastrophic failure under pressure. Testing every year does not align with typical regulations, which set specific intervals for hydrotesting based on usage and conditions. Additionally, the assertion that no testing is needed at all goes against the precautions necessary for safe handling of pressurized gases. Therefore, hydrotesting after a discharging event is a necessary safety measure to ensure continued safe operation of high-pressure cylinders.