Cylinder Filling & Hydrostatic Tests


Breathing air cylinders must be filled with clean, dry breathing air. Before cylinders can be refilled they must be within their current hydrostatic test period. The test period depends upon cylinder manufacture specification and ranges from 3-5 years for most portable breathing air cylinders and 1 year for cylinders used in underwater diving operations.

Cylinders are marked with a stamp into the neck region or a permanently affixed label on the cylinder body which will have the last hydrostatic test date. If a cylinder is out of the required test period it must be retested before it can be refilled.

Most cylinders currently used in industry are of composite design. These cylinders generally have an aluminium liner which is bound externally with a fibreglass fibre or in more recent times a carbon fibre wrap. This reduces weight for the end user. These cylinders have a service life of 15 - 20 years depending upon specification. Others might be extended out to 30 years. In the past, carbon composite cylinders were expensive compared with other designs. As they are now more common, cost is now very competitive and given the weight saving advantage of the cylinder, it it well worth considering.

While less common these days, some steel cylinders are used in some applications where wear and tear of the cylinder is a major consideration. Steel cylinders basically have an unlimited service life unless they fail test due to corrosion or damage. They are however heavy and subject to internal rust if not filled with dry breathing air.

Safety Air can provide hydrostatic testing of cylinders, cylinder refilling and supply new breathing air cylinders.

Contact our service technicians for further advice.

Please note! Cylinders filled for use in Australia must have a registered Australian test station mark and have Australian design approval / notification. While equipment is advertised on overseas web sites, it is recommended that you do not purchase equipment direct from overseas as the cylinder is unlikely to be design approved hence cannot be filled, nor will equipment meet Australian requirements.

Safety Air Pty.Ltd. provides quality and cost-effective
service for all makes and models of respiratory
protection equipment.


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