Understanding ISO 8573-1:2010 and the Importance of Compressed Air Quality

Air quality plays a vital role in workplace productivity, equipment performance, and product quality. To ensure consistency across industries, the International Organization for Standardization (ISO) has defined six classes of compressed air purity under the ISO 8573-1:2010 standard.

When air is compressed to 7 bar(g), the concentration of contaminants can increase by up to 800%. These contaminants—such as oil, water, and solid particles—can damage tools, cause product defects, and reduce the lifespan of pneumatic systems.

Contaminated compressed air can lead to:

• Erosion and scoring of system surfaces

• Rust and corrosion in piping, tools, and equipment

• Malfunctioning or damaged instrumentation

• Defective or blemished paint finishes

• Increased product rejection rates

• A less safe and uncomfortable work environment

What Is ISO 8573-1:2010?

ISO 8573-1:2010 is the most widely used air quality standard for compressed air systems. It defines air purity classes based on three types of contamination:

1. Particulate (solid particles)

2. Water (vapour and liquid)

3. Oil (aerosols and vapour)

Each is assigned a class number to indicate its acceptable concentration in a given application.

General-Purpose Oil-Free Air: Class 2.4.2

For many industrial applications, Class 2.4.2 air quality is sufficient. This corresponds to:

• Particulate (Class 2):

  • ≤ 400,000 particles (0.1 to 0.5 µm)

  • ≤ 6,000 particles (0.5 to 1 µm)

  • ≤ 100 particles (1 to 5 µm)

• Water (Class 4):

  • Pressure dewpoint ≤ +3°C

  • No liquid water allowed

• Oil (Class 2):

  • Total oil content ≤ 0.1 mg/m³

Meeting these standards ensures your compressed air is clean enough for general-purpose industrial use—preventing equipment failure, improving product consistency, and maintaining a safe and efficient working environment.