Knowledge Centre


Compressed Air Quality for Breathing Apparatus


Compressed air for breathing apparatus such as air fed masks or air tanks normally originates from a compressor system. These systems themselves can generate and concentrate a wide range of contaminants that can have an impact on the air quality being supplied.

The air quality can be effected in the following ways:

  1. Carbon Dioxide exhaust fumes can contaminate the compressor

  1. Carbon Monoxide can be drawn into the air intake from the compressor motor

  1. Oil Mist lubricants leaking from within the compressor can cause oil mist in the airline.

  1. Oxygen levels can be affected with a dryer malfunction.

  1. Water Vapour levels are important to prevent condensation or freezing of water in the airline.

As the users life and health depends on the air supplied by the compressor, you should ensure that the air supplied meets the quality requirements shown below and outlined within BS EN 12021:

The COSHH ACoP and HSG53 recommends that periodic air quality tests should be carried out at least every three months, and more often when the quality of air cannot be assured to these levels. These test records should be kept for a minimum of 5 years.

Compressors are available which include purifiers with automatic self-monitoring systems. These may be used as a substitute for periodic testing of the air quality if they can remove and effectively monitor for contaminants. If the system can monitor for all the contaminants then some additional procedures will need to be put in place as follows:

  • The monitoring system has been shown to be reliable for the substances being monitored

  • The air quality monitoring takes place at a suitable point in the supply line

  • Safety systems are in place to cope with possible malfunctions of the self-monitoring system.

If such a system is fitted and used, the need for quarterly periodic testing of air quality may not be necessary, however, it will not be possible to dispense with periodic testing of air quality altogether as the system is an engineering control. 

COSHH regulations require that thorough examination and testing is still required for engineering control systems on an annual basis.

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