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Compressed Air Contaminants & Purity Classes (ISO 8573-1:2010)
Understanding ISO 8573-1:2010
At Basil V.R. Greatrex, we help organisations across Australia understand, achieve, and maintain the required compressed air purity levels for their operations. Whether you’re in manufacturing, food production, electronics or pharmaceuticals, proper air treatment is critical to the performance, reliability, and safety of your compressed air system and ultimately, your end products.
What Is ISO 8573-1:2010?
ISO 8573-1:2010 is the internationally recognised standard for classifying compressed air quality. It defines the maximum allowable levels of three primary types of contaminants in compressed air systems:
Solid Particulates – Dust, rust, and other particles that can damage sensitive equipment, reduce efficiency, or compromise product quality.
Water (Moisture) – Vapour and condensed water that can cause corrosion, freezing, and hygiene issues in sensitive environments.
Oil – Mists and vapours originating from compressors or external sources that can lead to system failure, contamination, and product spoilage.
The ISO 8573-1 purity classification is expressed as: ISO 8573-1:2010 [A:B:C]. Where:
- A = Particles
- B = Water
- C = Oil
Purity Class | PARTICLES | WATER | OIL | |||||
Maximum number of particles per m³ | Particle | Concentration | Vapour | Liquid | Total oil ** | |||
0.1µm < d ≤ 0.5µm | 0.5µm < d ≤ 1.0µm | 1.0µm < d ≤ 5.0µm | µm | mg/m³ | PDP °C | g/m³ | mg/m³ | |
0 | As specified by the equipment user or supplier and more stringent than class 1 | |||||||
1 | ≤ 20,000 | ≤ 400 | ≤ 10 | – | – | ≤ -70 | – | ≤ 0.01 |
2 | ≤ 400,000 | ≤ 6,000 | ≤ 100 | – | – | ≤ – 40 | – | ≤ 0.1 |
3 | – | ≤ 90,000 | ≤ 1,000 | – | – | ≤ – 20 | – | ≤ 1 |
4 | – | – | ≤ 10,000 | – | – | ≤ + 3 | – | ≤ 5 |
5 | – | – | ≤ 100,000 | – | – | ≤ + 7 | – | – |
6 | – | – | – | 5 | ≤ 5 | ≤ + 10 | – | – |
7 | – | – | – | 40 | ≤ 10 | – | ≤ 0.5 | – |
8 | – | – | – | – | – | – | ≤ 5 | – |
9 | – | – | – | – | – | – | ≤ 10 | – |
X | – | – | – | – | ≥ 10 | – | ≥ 10 | ≥ 5 |
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** ISO 8573 Oil includes aerosol, vapour in the range of C6+, and liquid oil. Liquid oil is typically sampled when wall flow is present, contamination is suspected, or results are greater than 5 mg/m³. | ||||||||
By understanding your required purity class, you can design or upgrade your compressed air system to match the demands of your industry and avoid operational risks like product failure or non-compliance.
Key components such as compressed air dryers, filters, oil/water separators, and drains each play a vital role in removing contaminants like moisture, oil, and particulates. These elements work together to protect your compressed air system, downstream equipment, and the integrity of your final products.
We partner with facilities of all sizes, from production plants to laboratories, to ensure compressed air systems are compliant, efficient and reliable.
Our Services Include:
- Supply of filtration and drying units tailored to purity class requirements
- System audits and design reviews for ISO compliance
- On-site contaminant testing and report
- Preventive maintenance to uphold air quality standards
- Operator training in system monitoring and documentation
Why Up-to-Date Standards Matter
All of our work is based on the most up to date ISO standard. Using outdated references can lead to:
- Non-compliance with auditors
- Quality issues in sensitive applications
Always reference ISO 8573-1:2010 to ensure consistency across vendors, specs, and audits.
Common Mistakes and Misinterpretations
Misunderstanding compressed air purity classes can lead to costly errors. Some of the most common include:
- Over-specifying purity levels adds unnecessary cost and complexity.
- Misreading codes (e.g., assuming [1:2:1] applies to just particles).
- Ignoring oil vapour, especially in food and pharma.
Consulting with a compressed air specialist early in the design or upgrade process helps you avoid these issues and ensures your system is built for compliance and long-term performance.
Talk to Basil VR Greatrex Today
Whether you’re upgrading an existing system or starting from scratch, choosing the right ISO class is crucial.
Get in touch with the team at Basil V.R. Greatrex for a comprehensive compressed air quality assessment.
