Breathing Air Quality Testing

Why breathing-air testing matters

Compressed air used for tools, controls or production machinery does not necessarily require the same quality as air supplied to breathing apparatus.

Where people use air-fed masks, visors, hoods, helmets or airline breathing apparatus, the supplied air must be suitable for breathing. Contamination can create serious health risks and leave employers unable to demonstrate that their respiratory-protection controls are effective.

Testing helps you:

• Protect employees using air-fed respiratory equipment
• Identify contamination before it becomes a safety issue
• Support COSHH risk assessments and audit requirements
• Maintain documented evidence of air quality
• Check that filtration, drying and compressor maintenance are performing as intended
• Identify issues with compressor intake location, drainage, pipework or treatment equipment

Who needs breathing-air quality testing?

Testing should be considered wherever compressed air is supplied directly to people through breathing apparatus or air-fed respiratory protective equipment.

This includes sites involved in:

Paint spraying and coating

Air-fed respiratory protection is commonly used in spray booths and paint applications, particularly where isocyanate-containing coatings are used.

Vehicle repair and bodyshops

Spray-painting environments can present a higher risk of contamination entering the breathing-air supply, particularly where compressor intake conditions and maintenance are not tightly controlled.

Blast cleaning and surface preparation

Blast operators may rely on airline-fed helmets and hoods for respiratory protection.

Manufacturing and process industries

Operations involving coatings, chemicals, dust, fumes or airborne contaminants may use supplied-air respiratory protection.

Confined-space, emergency or specialist maintenance work

Any application using compressor-supplied breathing apparatus should be assessed to confirm the air supply is suitable and appropriately tested.

What do the regulations and standards require? Breathing air testing to BS EN 12021:2014

Employers have legal duties under the Control of Substances Hazardous to Health Regulations 2002 (COSHH) to prevent or adequately control employee exposure to hazardous substances.

Where respiratory protective equipment is used as part of those controls, it must be suitable, properly maintained and capable of protecting the wearer.

For compressed breathing air, the recognised technical standard is BS EN 12021:2014 – Respiratory equipment: compressed gases for breathing apparatus.

This standard sets quality requirements for compressed breathing air, including limits and controls around contaminants such as:The standard covers core aspects of breathing-air quality including:

Oxygen content

Carbon monoxide

Carbon dioxide

Oil content

Water content / dew point

Odour and taste

Where a site risk assessment identifies further potential hazards – such as vehicle exhaust, solvent vapours or process emissions near the compressor intake – the appropriate additional testing should also be considered. The exact testing programme should reflect your risk assessment, equipment, operating environment and maintenance regime.

Why breathing air quality matters

Contamination is not always visible, audible or obvious.

It can enter the system through the compressor intake, during compression, through inadequate treatment, or further downstream in storage, pipework and point-of-use equipment.

Common risks include:

• Compressor intakes located near vehicle movements, boiler flues or process emissions
• Oil carryover or unsuitable filtration
• Excess moisture or condensate within the system
• Corrosion or particles in pipework
• Changes to production, compressor location or operating conditions
• General factory compressed-air outlets being assumed suitable for respiratory use

The critical question is not simply whether the compressor has been serviced.

It is whether the air reaching the person wearing the mask, hood or helmet is suitable to breathe.

How often should breathing air be tested?

Breathing-air quality testing should be carried out at intervals determined by risk assessment.

As a general benchmark, HSE guidance indicates that air supplied to breathing apparatus should normally be tested at least every three months.

More frequent checks may be appropriate where:

• The system is used in higher-risk environments
• The compressor or breathing-air equipment has been moved
• Intake-air conditions may have changed
• Filters, dryers or treatment equipment have been replaced or repaired
• There is a concern about contamination
• The system is used in paint-spraying or bodyshop applications

For some higher-risk vehicle spray-painting environments, monthly breathing-line checks may be required.Your testing programme should reflect the site’s risk assessment, the application and the equipment in use.

A complete breathing air supply needs more than a compressor

Breathing-air quality is affected by the entire system:

Intake air → compressor → air treatment → storage → distribution → point of use → respiratory equipment

A standard workshop compressor may be part of a suitable breathing-air arrangement, but it should never be assumed that ordinary process air or a general factory outlet is safe for respiratory use.

The system needs the right intake location, treatment, maintenance, testing and controls for the application. HSE guidance makes clear that breathing apparatus requires a supply of breathing-quality air from an independent source, such as an air cylinder or compressor.