The appropriate British Standards for Inspection and Testing of diving cylinders are BS EN 1968.2002 (steel) and BS EN 1802.2002 (aluminium).
These lay down the techniques to be used, the measurements to be made and the frequency of tests.
Diving cylinders should undergo a visual inspection every 2.5 years and a hydraulic test every 5 years
During Visual Inspection the external and internal surfaces of the cylinder are examined for flaws/damage and the surfaces will be appropriately cleaned as necessary. The cylinder and valve threads will be checked for form and wear using plug and ring gauges. These gauges require annual certification for conformity.
Before a cylinder is hydraulically tested it has to pass a visual inspection. Then it is filled with water and subjected to its test pressure. The technician verifies and records using a test gauge (which is checked for calibration monthly) that it returns to its original volume, within limits. Now the cylinder is dried, reassembled and filled with clean air to its working pressure.
DV Diving use the latest optical, electronic and mechanical equipment to ensure that your cylinders can be inspected, tested, cleaned and dried to the highest standards.