In order for a cylinder to be filled with air it must have a valid test stamp or sticker. If this is out of date, or is not present, then the cylinder will not be filled and must undergo testing - this is a legal requirement. Cylinders must be hydrostatically tested every 5 yearsCylinders used for paintball will have the cylinder tested only. The regulator will not be serviced.
Cylinder Test Process:
- The cylinder will be inspected externally - the boot will be removed along with any stickers or labels so that any rusting or damage can be inspected. If there is significant surface corrosion or damage then the cylinder will likely fail.
- The valve will then be removed for testing.
- The cylinder neck thread will be checked with a measuring gauge to ensure it is undamaged and tight. If the cylinder neck thread test fails, then the cylinder will not be returned and will be scrapped due to the risk of catastrophic failure
- The cylinder will be inspected internally for defects, rust spots etc. If there is internal damage, the cylinder is not economically repairable and will need to be scrapped.
- The cylinder is then tested for its ability to return to its normal capacity after being subjected to pressure of 150% of its maximum operating pressure.
- Reassembly and filling.
Cylinders serviced through Dive Force will be returned full.
In the event that the cylinder fails its hydrostatic test, the regulator only wil be returned. There is no refund. The cylinder will be destroyed in accordance with UK regulations.
Why must high-pressure cylinders be tested?All high pressure cylinders with an internal volume greater than 0.5 litres must be hydrostatically tested every 5 years from the date of manufacture (stamped on the cylinder) to ensure that the cylinder is structurally sound.
What is a hydrotstaic test?
A hydrostatic test is an approved way to test the structural integrity of a high-pressure compressed gas cylinderIt is carried out by removing the valve, filling the container with water, and then pressurising the cylinder above its operating limit. The expansionof the cylinderis measured, recorded, and analyzed. All high pressure cylinders with an internal volume greater than 0.5 litres must be hydrostatically tested every 5 years.
Why do air gun cylinders only need testing every 5 years?
Cylinders not used for scuba diving that have a special surface valve fitted, only require hydrostatic tresting every 5 years. This is because there is little risk of water entering the cylinder.
Why do scuba cylinders require testing every 30 months?Cylinders used for scuba diving must be tested every 30 months due to the risk of water getting inside the cylinder. The test will either be a visual test with valve service, or a hydrostatic test with valve service. Hydrostatic tests must be carried out every 5 years.
Why must cylinders be cleaned for Nitrox/Trimix?
Scuba cylinders that are used for Nitrox/Trimix must be specially cleaned for use with oxygen. This is because nitrox mixes are typically prepared by emptying the cylinder first, then adding 100% oxygen to the required amount before topping up with air to get the right mix. Oxygen cleaning must be carried out every 18 months due to the risk of contamination.
Why might a cylinder require an internal shot blast?
It is possible that steel cylinders may accumulate rust on the internal surface of the cylinder. This could be due to water getting into the cylinder or from air fills that contain hugh levels of moisture. Rust if severe can lead to weakening of the cylinder wall and therefore the cylinder being condemned. Small amounts of surface rust can removed through shot blasting the inside of the cylinder with particles.
