EN12021:1999

The quality of compressed air used in breathing apparatus is specified in the European Standard EN12021:1999 'Respiratory protective devices - Compressed Air for breathing apparatus.'

It is vital that the quality of compressed air used in respiratory applications is in accordance with the required standards to prevent risk to human health and corporate reputation.

The standard specifies that in all circumstances all contaminants shall be kept to levels below the national occupational exposure limits as defined by the Health and Safety Executive (EH40)

The standard applies to self contained compressed air breathing apparatus used above and under water (SCUBA). It also applies to systems supplying breathing air via an air line, escape devices and systems supplying synthetic air.

Requirements are specified in the standard for permissable levels of oxygen, lubricants, odour, taste, carbon dioxide, carbon monoxide and water content in compressed breathing air. The levels are summarised in the following table.

The requirements stipulate that there should be no free liquid water visible in the breathing air supply.

Air used in breathing air supplies is also required to have a dewpoint low enough to prevent condensation and freezing. When the breathing air is used or stored in an area where the ambient temperature is known the pressure dewpoint has to be at least 5 Deg C below the envisaged lowest temperature. Generally in cases where the lowest temperature cannot be predicted the pressure dewpoint is specified not to exceed -11 Deg C.

The maximum permissable water content of air at atmospheric pressure is also specified and summarised as follows

Air @ nominal pressure 40-200 bar, maximum water content is 50 mg / m3

Air @ nominal pressure > 200 bar, maximum water content is 35 mg / m3

The standard also states that the maximum water content of compressed air used to fill 200 or 300 bar g cylinders should not exceed 25 mg/m 3.

Safewell provides a complete process for evaluation and implementation of solutions to purify compressed air in accordance with the prescribed quality standards. We specify a full range of compressed air purification equipment and integrate these cost effectively to provide a complete solution taking into account factors such as energy efficiency, lifecycle maintenance and cost of ownership.