Breathing Air Quality Testing

If you are using compressed air as breathing air you have a legal requirement, as stated in EN12021, to regularly test and certificate the breathing air quality.

Our qualified engineers can carry out these tests and provide you with the relevant certificates. The required quality of breathing air is stated in EN12021 is to provide information on the safe limits of potential contaminant gases within breathing air and to ensure that the life support gas of oxygen is of an adequate level.


Compressed air for breathing normally originates from a compressor system installed or operating at the place of use and there are various factors that can affect the quality and safety of this air.


  • The air intake to the compressor can ingest airborne contamination from local processes and vehicle exhaust fumes which are not removed by standard breathing air filtration. Such air borne contamination may not be continuous but the pollution of the air supply may persist for hours or days.
  • Malfunctioning compressors, especially reciprocating type, can produce unsafe levels of both carbon monoxide and carbon dioxide.
  • Breathing air filtration has a finite life and can fail causing high levels of oil and water contamination to be present in the air.
  • The performance of desiccant filters is dramatically affected by operating temperature. Infrequent validation may result in poor quality air being supplied for an extended Period
  • Failure of the compressed air aftercooling will result in air entering the filtration at too high a temperature, this will cause the filtration to prematurely fail and pass excess levels of oil and water.
  • Malfunctioning dryers can disturb the oxygen concentration to outside safe levels within the breathing air.
  • High levels of water in breathing air can freeze within RPE demand valves causing the air supply to fail.
  • Insufficient air flow or pressure to the RPE will reduce the protection factor of the RPE and potentially expose the user to ingress of external contaminants.
  • The effects of contaminants when breathed at elevated pressure can have a much greater effect on users than it would at normal pressure.
  • Changes in the performance of compressor and filtration equipment are usually rapid in nature. Any failure affecting outlet air quality may injure users for an extended period if quality validation is infrequent.
  • Odour alone is a poor indicator of air quality, toxic as asphyxiant gasses are often odourless, the limits for oil pollution are lower than the threshold detection level that most people will notice.


Let ACL Engineering  provide you with peace of mind and certification by testing your breathing air system.


Call now on 01923 249444 to book your air quality testing.

Call 01923 249444 or email for more information