What is Compressor Air Quality Testing, and Why Does it Matter?
Testing checks compressed air systems for contaminants, including moisture, particles, and oil. Regular testing ensures system performance and compliance with industry standards. This protects equipment, products, and end users while optimising operational efficiency.
Atlas Copco’s air quality testing solutions include advanced equipment and methodologies, ensuring ISO 8573-1 compliance for even the most demanding industrial applications.
Below, Control Gear UK answers the question: what is compressed air quality testing? And explain the key elements and how they are done.
What is the ISO 8573-1 Compressed Air Quality Standard?
ISO 8573-1 sets the international standard for quality wherever compressed air is used. The British Compressed Air Society (BCAS) also offers advice, guidelines, and best practices for industrial compressed air applications.
According to ISO 8573-1, three main contaminants are classified:
- Particulate matter concentration determines the amount of solid contamination in the system.
- Moisture levels measure the amount of water vapour that can damage equipment or affect products.
- Oil content measures the amount of hydrocarbons that can compromise air purity.
Class 0 air quality exceeds Class 1 requirements, ensuring the purest air for critical applications such as food, pharmaceutical, and medical industries.
What is Compressed Air Testing?
Compressed air testing checks the level of contamination within a compressed air system by identifying major contaminants such as particles, moisture, oil vapour, and gases. It ensures air purity in line with ISO 8573 compressed air quality standards or BS EN 12021 when testing breathing air quality.
Specialist air quality testing equipment, such as laser particle counters and dew point sensors, is used to detect contaminants and ensure systems meet the quality requirements for specific applications. Whether testing process air for production lines or compressed breathing air for healthcare or diving, the goal is to maintain safe and high-quality air at all times.
Testing may be conducted in line or via sample extraction, and regular air quality monitoring is often recommended, especially in industries such as food, pharmaceuticals, and healthcare, where air purity is critical.
Control Gear works with accredited laboratories and leading tools to deliver a comprehensive system for evaluating air purity. This helps identify risks and optimise your source of compressed air to avoid costly issues and uphold compliance.
Why is Compressed Air Purity Needed?
Manufacturing and other equipment need clean air to perform optimally and prevent premature wear. Product quality depends on the air compressor supplying contamination-free air to ensure consistency throughout the production process. Consumer safety relies on pure compressed air use, especially in food, beverage, and pharmaceutical applications. Regulatory requirements demand specific air quality standards across industries. System failures happen when contaminants build up, costing you time and money to repair and downtime.
Atlas Copco’s oil-free compressors meet ISO Class 0 standards, delivering pure air with zero risk of contamination for sensitive industries.
Why Test Compressed Air?
Here are just a few reasons testing compressed air is a cost-effective preventative measure:
- Companies test compressed air in industrial processes to stay certified and meet industry standards.
- System problems show up through testing before they become major issues.
- Maintenance costs are lower when compressed air supply issues are found and fixed early.
- Product contamination risk decreases when you monitor the quality of compressed air.
- Industrial air equipment performance remains optimal when compressor systems are checked regularly.
- Unexpected shutdowns happen less often when air quality is maintained properly and compressors and air dryers are checked periodically.
Advanced testing techniques from Atlas Copco allow continuous monitoring to ensure consistent air quality.
How Air Quality Testing Works
Various procedures for testing can be used to measure the quality of compressed air, depending on the contaminant type:
Moisture Testing
Capacitive sensors monitor the dew point continuously to prevent condensation. Colour-changing indicators provide simple visual alerts when moisture levels are out of range. Chilled mirror devices are laboratory-grade for critical applications that require precise moisture measurement.
Humidity and Liquid Water
| Class | Pressure Dew Point °C | Pressure Dew Point °F | Water Concentration |
| 0 | As specified by equipment user/supplier, stricter than Class 1 | ||
| 1 | ≤ -70°C | ≤ -94°F | ≤ 0.003 g/m³ |
| 2 | ≤ -40°C | ≤ -40°F | ≤ 0.12 g/m³ |
| 3 | ≤ -20°C | ≤ -4°F | ≤ 0.88 g/m³ |
| 4 | ≤ +3°C | ≤ +37.4°F | ≤ 6 g/m³ |
| 5 | ≤ +7°C | ≤ +44.6°F | ≤ 7.8 g/m³ |
| 6 | ≤ +10°C | ≤ +50°F | ≤ 9.4 g/m³ |
Oil Content Analysis
Sampling boxes test compressed air quality by capturing oil aerosols and providing quick contamination level indicators. Glass tube indicators change colour based on oil vapour concentration for periodic testing. Photoionisation detection systems monitor volatile organic compounds (VOCs) in the air stream. Gas chromatography testing is done for the most demanding applications.
Oil Content (Liquid, Aerosol & Vapour)
| Class | Total Oil Content |
| 0 | As specified by equipment user/supplier, stricter than Class 1 |
| 1 | ≤ 0.01 mg/m³ |
| 2 | ≤ 0.1 mg/m³ |
| 3 | ≤ 1.0 mg/m³ |
| 4 | ≤ 5.0 mg/m³ |
Particle Measurement
Laser counting systems count and size particles in real time. Optical particle detection equipment measures contamination levels across multiple size ranges.
Atlas Copco’s particle counters deliver precise results, ensuring compliance with ISO 8573-1 standards for particulate matter.
Solid Particles
| Class | Maximum number of particles per m³ by particle size | ||
0.1 – 0.5 micron | 1.0 – 5.0 microns | 0.5 – 1.0 microns | |
| 0 | As specified by equipment user/supplier, stricter than Class 1 | ||
| 1 | ≤ 20,000 | ≤ 400 | ≤ 10 |
| 2 | ≤ 400,000 | ≤ 6,000 | ≤ 100 |
| 3 | Not specified | ≤ 90,000 | ≤ 1,000 |
| 4 | Not specified | ≤ 10,000 | |
| 5 | Not specified | ≤ 100,000 | |
Gas Detection Methods
The highest air purity testing employs gas chromatography, gas analysers, and electrochemical and sensor methods. The testing process is based on different sampling points, measurement parameters, and testing methods such as direct inline monitoring, sample extraction to analyser, bypass flow systems, and periodic spot checks.
Gas testing methods ensure that air quality meets specific industry requirements, such as medical-grade air standards for hospitals and laboratories.
Common Standards
| Gas | Typical Industrial Limit |
| Carbon Dioxide (CO2) | < 500 ppm |
| Carbon Monoxide (CO) | < 5 ppm |
| Nitric Oxide (NO) | < 2.5 ppm |
| Nitrogen Dioxide (NO2) | < 2.5 ppm |
| Sulphur Dioxide (SO2) | < 1 ppm |
| Hydrocarbons (HC) | < 5 ppm |
Microbiological Testing
Microbiological testing equipment examines the presence of bacteria, yeasts, and moulds in the compressed air sample. Testing methods include impact samplers, membrane filtration, Adenosine Triphosphate (ATP) testing, and particle counters calibrated for bio-detection.
Common applications for microbiological testing include the use of compressed air in clean rooms, medical air systems, food packaging areas, pharmaceutical manufacturing, and biotechnology facilities.
Industries that Need Compressed Air Quality Testing
- Food and beverage companies need clean air to prevent product contamination.
- Pharmaceutical companies need ultra-clean air to meet health and safety regulations and product safety.
- Medical facilities and first responders need pure air for patient care and equipment operation.
- Whether leisure scuba diving or offshore diving (oil industry), the diving industry relies on high-quality compressed breathing air.
- Electronics assembly plants need clean air to prevent microscopic damage to components.
- Automotive companies need contaminant-free air for painting and assembly processes.
- Chemical processing needs specific air quality for safety and product integrity.
- Food packaging needs clean air to keep products fresh and safe.
Atlas Copco’s compressed air solutions are tailored to meet the stringent demands of these industries, ensuring reliable and clean air supply.
Benefits of Air Quality Testing
Compressed air quality testing helps identify major contaminants in compressed air, including moisture, particulates, and the amount of oil present, before they impact your operations. It is a proactive step that supports both performance and compliance.
For industries that use gas for breathing or compressed air in direct contact with products such as food, pharmaceuticals, and healthcare, the need for safe breathing air is critical. Testing ensures compliance with breathing air standards, such as BS EN 12021 and ISO 8573-1, safeguarding both product quality and personnel.
Benefits include:
- Better efficiency: Clean air systems use less energy and reduce strain on components
- Extended equipment life: Prevents moisture and oil from damaging the air line and tools
- Product integrity: Essential in sectors where saturated air or air contaminants can lead to spoilage or rejection
- Audit-ready compliance: Documentation supports standards from ISO to the British Retail Consortium
- Smarter maintenance: Testing reveals issues within the compressed air system so they can be fixed before failure
Air quality testing also demonstrates your duty of care, showing that your facility takes appropriate steps to ensure that the breathing air or process air it delivers is clean, compliant, and efficient.
At Control Gear, we provide tailored testing solutions backed by Atlas Copco, helping you maintain the system for air purity designations outlined in ISO 8573 compressed air quality.
Control Gear – Your Air Quality Testing Partner
Our full evaluation service gives you detailed information about your compressed air system. Using advanced diagnostic tools, we carry out a full assessment to maximise efficiency. We measure multiple contaminant levels and identify opportunities to improve the quality of the air being used.
Clients benefit from industry-leading tools, including SMARTLINK monitoring from Atlas Copco, to maintain optimal air system performance.
Upon completion of the test, clients receive a professionally prepared report containing:
- Performance metrics
- Specific recommendations
- Technical guidance for maintenance
- Solutions for the issues found
- Compliance with industry standards
Discover the difference air quality testing can make to your operations with Control Gear’s expert services. Contact us today.
We turn complex data into practical advice so your facility runs at its best. Our experienced technicians will implement the recommendations and keep your system running optimally.
Discover the difference compressed air quality testing makes to your operations with Control Gear.
FAQ
What standards does compressed air quality testing need to meet?
Compressed air testing typically follows ISO 8573 compressed air quality standards, which define the major contaminants in compressed air, including particulates, water, and oil. For breathing air applications, BS EN 12021 is often required to ensure the air is safe to breathe and suitable for medical or food-grade use.
Why is regular air quality testing important in industrial settings?
Regular air quality testing helps identify air contaminants such as oil vapour and moisture before they cause damage within the compressed air system. It also supports compliance with sector-specific requirements, such as those outlined by the British Retail Consortium, and helps maintain consistent product quality.
What types of contaminants are checked during compressed air purity testing?
Compressed air purity testing checks for a range of contaminants including the amount of oil, dew point, solid particles, and in some cases, microbial content. These can originate from the source of contamination or ambient air, and if left unchecked, may compromise the safety, efficiency, and reliability of the air line or breathing air supply.