Diving equipment consists of breathing apparatus and air cylinders. Divers must take care of regular cylinder maintenance and inspections. Cylinders are filled using compressors, which are also subject to maintenance and inspection obligations.
New diving cylinders must carry the CE marking. Other compulsory safety markings are:
- Cylinder manufacturer;
- Year of manufacture;
- Maximum allowed filling pressure;
- Test pressure;
- Empty weight; and
- Valve thread specification indicating thread type and size.
Diving cylinders are usually colour coded with white and black markings on the shoulder. The rest of the cylinder is yellow. The cylinder valve must show the manufacturer's name, year of manufacture, pressure and thread specifications. When buying diving cylinders, pay attention to the markings and condition, especially if buying one second-hand or abroad. Do not forget to check out the markings to be sure the cylinder and the valve are compatible with each other.
Cylinders used in mixed gas diving must have specific markings to distinguish them from ordinary breathing air cylinders. The markings are affixed on stickers that indicate the gas mixture, diving depth and, if necessary, oxygen servicing. Cylinder oxygen cleanness and regular oxygen servicing are necessary, if the mixed gas has an oxygen content of 40% or above.
Diving cylinders are pressure equipment and must therefore be inspected regularly. Periodic inspections are performed by inspection bodies, with inspections of steel and aluminium cylinders due at 10-year intervals. The inspections take place at inspection facilities approved by inspection bodies. An inspection marking and inspection label specifying the year in which the next inspection is due is affixed to the cylinder following the periodic inspection.