Compressed air gets used across a range of industries to provide respiratory protection. It’s used in applications where the risk of breathing ambient air is too high to mitigate using half or full-face respirators.
But it is not safe to breathe the compressed air directly following compression. It needs to get filtered by a multistage breathing air filter.
In Europe, the required quality of breathing air is stated in BS EN 12021:2014, ‘Respiratory equipment. Compressed gases for breathing apparatus’. This provides information on the safe limits of potential contaminants, such as Carbon Dioxide, Water Vapour and Residual Oil and to ensure that oxygen is of an adequate level.
European breathing air standards:
| Odour | The gas must be free from unsatisfactory odour or taste |
| Oxygen | (21 ± 1)% |
| Carbon Dioxide | ≤ 500 PPM |
| Carbon Monoxide | ≤ 5 PPM |
| Oil | ≤ 0.5 mg/m3 |
There are many factors which can affect the safety and quality of the breathing air, for example:
- Malfunctioning compressors can produce unsafe levels of carbon monoxide and carbon dioxide.
- Breathing air filtration can fail causing contamination to be present in the air.
- The compressor air intake can get polluted by airborne contamination. This can come from nearby processes and vehicle exhaust fumes. This does not get removed by standard breathing air filtration.
- Insufficient air flow or pressure to the respiratory protective equipment (RPE) reduces the protection factor and can expose the user to external contaminants.
All employers have a duty of care to ensure that the breathing air they supply to their employees is safe to breathe. The only way to check that the air supply is fit breathing is by regular testing.
How often should breathing air quality get tested?
Breathing air quality needs to get tested routinely to make sure control measures get put in place to maintain the quality required.
In the HSE guideline document Respiratory Equipment at Work (HSG53) it states the frequency of such tests should be based on a risk assessment. It should happen at least every three months, and more often when the quality of air cannot be assured to these levels.
Want to find out more details about what's involved in a breathing air test? Read the full blog on our website: https://www.directair.co.uk/news/breathing-air-your-compressed-air-responsibilities/