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Why do we carry out breathing air quality tests?

Breathing air quality tests are typically carried out where breathing apparatus is connected to a compressed airline, where there are a number of factors that could contaminate this air and potentially compromise the safety of the spray booth painter.

In accordance with HSE and COSHH regulations, spraying of paint containing isocyanates must be carried out under controlled circumstances. The appropriate PPE (Personal Protective Equipment) to protect painters requires them to connect a full face breathing mask to a compressed airline. The national standard BS:EN12021 advises these tests should be carried out and analysed at least every 3 months, or more frequently if there has been a change in process, for example a new compressor installed.

Compressed air breathing quality – what we test

In compliance with the BS EN12021 legislation, all environments where air is supplied through a compressor must be absolutely free from harmful contaminants/substances.

Here are some of the guidelines set out by the BS EN12021 with regard to compressed air:


In order to maintain a healthy breathing environment, oxygen levels must be set at 21% +/- 1%.

Odour and taste of compressed air

To best simulate natural air, the odour/taste of compressed air must be ‘without significant odour or taste’.

Carbon monoxide

A highly dangerous gas, carbon monoxide levels must be under 5ppm (parts per million).

Carbon dioxide

Carbon dioxide levels must be under 500ppm.

Oil mist/vapour

Any oil mist/vapour levels must be under 0.5mg/m³.

Water airline

Furthermore, our compressed air quality tests must show a dew point that is low enough to prevent condensation and freezing. With this in mind, the dew point of the air must be at least 5oC below the lowest temperature. Lastly, the pressure dew point cannot exceed -11oC.

Where do contaminants come from?

Contaminants can enter compressed air by a number of means. For example, when a failed air compressor creates oil in the air line, toxic and volatile substances can then foster. More commonly, contaminants come from the air intake of the compressor. If it draws in carbon monoxide or carbon dioxide from an outside source, this can pose a huge threat to workers.

Reduce costs and ensure compliance with AGM Services

With our annual service program, you can start reducing costs and improving productivity in your work premises. Compliance not only poses risks to the health of your staff, but it can cost you a fortune in the long-run.

Take a look at our Breathing Air Quality test services, as well as our wider legislative testing. We provide a comprehensive service to ensure that all of your processes are healthy and compliant to the HSE, COSHH, and other governing bodies. Get in touch for more information regarding spray booth maintenance and servicing.

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