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Breathing Air Quality Testing

At J Ll Leach, we specialise in providing comprehensive breathing air quality testing services to ensure your air systems comply with stringent safety regulations.

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Air Quality Testing

Employers have a duty of care to ensure that the compressed breathing air they supply to their employees is safe to breathe. This is a mandatory legal and safety requirement under UK regulations. Poor air quality in compressed air systems can contain contaminants at a concentration that exceeds the quality required under the current BS EN 12021:2014 standard, posing harmful effects on workers. Regular compressed air testing ensures compliance with ISO standards and safeguards workplace safety.

Mandatory Testing Frequency

HSE guidance and COSHH regulations recommend that testing must take place at least every three months. The frequency of such tests may need to be increased if:

  • The source of compressed air changes or equipment is relocated.
  • Maintenance is carried out on air dryers, pipework, or filtration systems.
  • The point of use involves paint shops, Respiratory Protective Equipment (RPE) such as respirators, or industrial gas outlets.

Common Contaminants and BS EN 12021:2014 Limits

  • Carbon Monoxide (CO): A highly toxic gas often generated by the overheating of compressor lubricating oil (oil coking) or from engine exhaust fumes drawn into the compressor intake. The legal limit under BS EN 12021:2014 is extremely low, at a maximum of 5 parts per million (ppm).
  • Carbon Dioxide (CO₂): Typically ingested from the ambient air, such as from vehicle exhaust. The maximum limit is 500 ppm.
  • Oil mist and vapours are present in standard air compressor systems, requiring multi-stage air filters. The standard sets a strict maximum limit of 0.5 mg/m⁻³.
  • Water vapour and humidity lead to corrosion, bacterial growth, and reduced efficiency of desiccant dryers. The standard requires a specific pressure dew point (PDP) to be met, typically 5°C below the lowest likely ambient temperature, or not exceeding -11°C for unknown conditions, to prevent freezing and condensation.
  • Particles and impurities can clog downstream normal pipe outlets and reduce air quality index (AQI) levels

What Does Testing Involve?

A standard compressed breathing air testing process checks for:

  • Oxygen (O₂) levels (which must be 21% ± 1%)
  • Toxic gases (CO, CO₂) against their specific ppm limits
  • Impurities and filtration efficiency
  • Moisture content (Pressure Dew Point)
  • Odour and taste, to ensure the air is clean.

Why Regular Testing is Essential

  • Employers have a duty to ensure compliance with BS EN12021 and ISO standards.
  • It prevents costly contamination issues in compressed air and is used for respirators, paint shops, and critical applications.
  • It protects employee health by maintaining an air quality index suitable for breathing.

At J Ll Leach & Co Ltd, we provide compliant compressed air testing services to ensure the safety of employees and meet your legal duty of care.

What Are the Legal Requirements for Breathing Air Testing?

BS EN12021:2014 is the current UK standard to indicate contaminant levels for breathing-air both in the UK and in the EU expressed as “in any event all contaminants shall be kept to as low a level as possible and shall be less the national exposure limit“, but the following guide may help employers to know the specific regulations as they apply to a variety of industry requirements:

  • Management of Health and Safety at Work Regulations 1999 (SI 1999/3242) – requires a safe working environment by the application of risk assessment procedures.
  • The Personal Protective Equipment Regulations 2002 (SI 2002/1144) Schedule − refers to the design and manufacturer of respiratory protective equipment.
  • The Work in Compressed Air Regulations 1996 (SI 1996/1656) − these regulations deal with those aspects where the user is operating in a pressure higher than atmospheric, e.g. tunnelling.
  • The Pressure Systems Safety Regulations 2000 (PSSR): Governs the integrity and safety of the compressor system itself. A failure in mechanical integrity (e.g., overheating) is a primary cause of air quality contamination.
  • Control of Substances Hazardous to Health (COSHH) Regulations 2002 (SI 2002/2677 − also as amended by S.I. 2004 No. 3386 in respect of the term “workplace exposure limit”) − these regulations identify the maximum exposure limits for a defined list of contaminants which may be present in a workplace atmosphere. COSHH places a direct responsibility on the employer (as the ‘Duty Holder’) to ensure the RPE is fit for purpose and that air quality is tested by a ‘Competent Person’.

The exposure limits are now identified by the single term “workplace exposure limit (WEL)” which encompasses both long- and short-term exposure. Related to COSHH is a reference listing published annually under the identity EH40 “Occupational Exposure Limits”. 

The listings are in addition to those in COSHH. Where any doubt exists as to the limits for any contaminant then this should be used as a start point.

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Industries That Require Frequent Testing

Sectors where compressed air is used for breathing apparatus must maintain strict air quality:

  • Manufacturing and Engineering – ensures clean air in production environments.
  • Healthcare and Pharmaceuticals – prevents contamination in sterile settings.
  • Construction and Tunnelling – protects workers using compressed air breathing apparatus (CABA).
  • Automotive and Spray Painting – avoids airborne pollution that affects finishes and worker health.

Ready to Ensure Your Air Quality is Safe?

Here at J Ll Leach & Co Ltd, we can offer this breathing air quality testing service for you using our team of competent staff using the latest test equipment. Our engineers act as your appointed ‘Competent Person’ to ensure you meet all your legal obligations under COSHH and BS EN 12021:2014.

Please note we cannot carry out a particulate test as required under BS EN 12021.

Why not contact [email protected] for more information on what we can do for you?

FAQ

How often should I test my breathing air supply?

To comply with BS EN 12021, breathing air quality should be tested by a competent person at least every three months. This frequency may need to increase depending on the circumstances precautions need to be taken. Factors such as changes in compressor uses needs, system modifications, or environmental conditions may require more frequent checks to ensure all gas for breathing remains safe.

Why is it important to test the correct level downstream?

Testing the correct level downstream ensures that air remains compliant throughout the system, including at the point of use. Contaminants such as oil mist, moisture, and carbon monoxide can accumulate in pipework, affecting air purity. Regular checks help maintain consistent quality throughout the system, preventing safety risks.

How can I ensure my system stays compliant?

Routine testing and preventative maintenance are key. Regularly service your compressors, replace filters and desiccant, check filtration efficiency, and monitor downstream air quality to prevent contamination. This is the most effective way to prevent system failures that lead to contamination from oil, CO, or moisture. If you are unsure whether your air supply meets BS EN 12021:2014 standards, talk to us for expert guidance and testing solutions.

What are the key limits in the BS EN 12021:2014 standard?

While the full standard is detailed, the five key contaminant limits a ‘Competent Person’ tests for are:

  • Oxygen (O₂): 21% ± 1%
  • Carbon Monoxide (CO): ≤ 5 ppm
  • Carbon Dioxide (CO₂): ≤ 500 ppm
  • Oil Mist/Vapour: ≤ 0.5 mg/m⁻³
  • Water/Dew Point: Must be low enough to prevent condensation, not exceeding -11°C if the operating temperature is unknown.