More than 70% of production facilities use compressed air in the manufacturing process.
If the compressed air becomes contaminated, it will adversely affect the quality of the product. Proper assessment of the compressed air system, and regular testing can prevent serious contamination and promote the overall health of the system. Ensuring that compressed air is not a source of contamination is essential to producing a high-quality product.
Prevent product contamination
- Rusty Particles
- Excess Water
- Oily Piping
- Mold and Bacteria
Meet certification requirements
- SQF - Safe Quality Food
- FDA - Food and Drug Administration
- BRC - British Retail Consortium
- PrimusGFS - GFSI Scheme
Monitor the health of your system
- Compressor Fittings
- Distribution Piping
- Storage Receivers
Meet equipment requirements
- Class 0 Oil
- Clean Dry Air
ISO 8573 is an internationally recognized standard that defines major contaminants in compressed air and presents a comprehensive system for air purity designations. The implementation of this standard supports accurate testing of the major contaminants in compressed air - particles, water, oil, and microorganisms. ISO 8573 is used widely throughout the compressed air industry, acting as a common language available to the manufacturer, compressed air system supplier, and compressed air testing laboratory.
Provides analytical methods
and sampling techniques
- Laser Particle Counter
- Detector tubes
- Gas chromatography
Aligned with current compressor
and filtration capabilities
- Atlas Copco
- Parker Hannifin
Comprehensive purity designations
- Particle Classes 1–9
- Water Classes 1–6
- Oil Classes 1–4
| International Standard: ISO 8573-1:2010 Compressed Air Contaminants and Purity Classes |
When defining your purity classes for Particles, Water, and Oil, it is formatted as ISO 8573-1:2010 [P:W:O].
| Class || Particles || Water || Oil |
| By Particle Size|
(maximum number of particles per m3)
| By Mass || Vapor Pressure Dewpoint || Liquid || Liquid, Aerosol, & Vapor |
|0.10 – 0.5 microns||0.5 – 1.0 microns||1.0 – 5.0 microns||mg/m3||°C||°F||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||≤ -94||-||≤ 0.01|
| 2 || ≤ 400,000 ||≤ 6,000||≤ 100||-||≤ -40||≤ -40||-||≤ 0.1|
| 3 ||-||≤ 90,000||≤ 1,000||-||≤ -20||≤ - 4||-||≤ 1|
| 4 ||-||-||≤ 10,000||-||≤ +3||≤ +37||-||≤ 5|
| 5 ||-||-||≤ 100,000||-||≤ +7||≤ +45||-||-|
| 6 ||-||-||-||0 – ≤ 5||≤ +10||≤ +50||-||-|
|7||-||-||-||5 – ≤ 10||-||-||≤ 0.5||-|
|X||-||-||-||> 10||-||-||> 10||> 5|
| || Microbiological Contaminants || Other Gaseous Contaminants |
| ||No purity classes are identified||No purity classes are identified|
Gases mentioned are: CO, CO2, SO2, NOX, Hydrocarbons
Note 1: ISO 8573 Oil includes aerosol, vapor 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. Trace can provide a separate kit for liquid oil testing.
Note 2: For Particle Class 0, 1, & 2 (0.1 - 0.5 µ range only), a laser particle counter with a high-pressure diffuser is required. Rental of this equipment is available on a reservation basis. Contact us for details. To qualify for Particle Classes 0 through 5, there can be no particles greater than 5µ present.
In some cases, Trace uses alternative sampling techniques or analytical methods to those specified in ISO 8573, for details see Smith White Paper, 2012.
Compressed air quality monitoring and testing provides valuable data to identify trends, create a trackable quality assurance plan, and implement preventative measures.
Compressed air is susceptible to contamination in multiple ways. Select a purity class based on product or equipment requirements, risk factors, industry, corporate mandate, and QMS protocols. The particle contaminant class can be different from the other contaminants listed.
ISO 8573-4:2001 specifies sampling techniques and test methods based on counting particles by size. Classes 1–5 can have no particles greater than 5 microns present and are harmonized with current available filtration.
ISO 8573-8:2004 specifies sampling techniques and testing methods for determination by mass concentration for Classes 6, 7 and X, and is intended for industrial tools and pneumatic-fluid power-operated machines traditionally supplied with general purpose filters with particle size rating of 5 micron (class 6) and 40 micron (class 7).
Water vapor present in a compressed air systems is dependent on the type of dryers/water removal filters installed.
ISO 8573-3:1999 specifies sampling techniques and test methods for pressure dew point. Classes 1-3 are appropriate for air filtered by desiccant dryers, and Classes 4-6 are appropriate for air filtered by refrigerated dryers.
Liquid water classes 7-X (ISO 8573-9:2004) are typically not applicable to critical applications.
Oil is defined as a mixture of hydrocarbons composed of six or more carbon atoms, i.e., C6+. Even an oil-free compressor can become contaminated from oil aerosols and vapors introduced through the compressor intake.
ISO 8573-2:2007 specifies sampling techniques and testing methods for oil aerosol content, and ISO 8573-5:2001 is for oil vapor and organic solvents. Purity classes 1 & 2 require both oil aerosol and oil vapor measurements. Class 3 & 4 can be just oil aerosol. Liquid oil testing applies when heavy contamination levels of oil are suspected or wall flow is present.
Tens to hundreds of bacteria per cubic meter can be found in normal ambient air alone. Methods for testing microbiological contaminants in compressed air are specified in ISO 8573-7. No purity classes are defined for microbiological contaminants.
Test methods for gaseous contaminants are addressed in ISO 8573-6 (LINK). No purity classes are defined for "other gases".
Choose purity classes based on product requirements, installed filtration, risk factors, QMS protocols, corporate mandate, and/or regulating organization. If uncertain as to which classes to select, request a BASELINE analysis. The laboratory will evaluate test results and rate by purity class.
Particle Class 1 includes 3 size ranges for particulates. A Laser Particle Counter (LPC) with a high-pressure diffuser is required for particles 0.1–0.5 microns. Oil classes 1 & 2 require both oil aerosol and oil vapor to be determined.
Particle Class 2 includes 3 size ranges for particulates. A Laser Particle Counter (LPC) with a high-pressure diffuser is required for particles 0.1–0.5 microns. Oil classes 1 & 2 require both oil aerosol and oil vapor to be determined.
Particle class 3 only requires 2 particle size ranges.
Particle class 4 includes only one particle size range.
Particle class 5 includes only one particle size range.
ISO 8573-1 states that there can be no particles greater than 5 microns for Classes 1-5 and that Class 6 & 7 are appropriate for compressed air filtered by general-purpose filters typically used for industrial tools and pnematic-fluid power-operated machines. Liquid water and liquid oil classes are typically used when contamination is suspected.
SHADED area indicates 0.1 – 0.5 micron particle range in Class 1 must be analyzed using an onsite laser particle counter. *Trace Analytics, LLC provides rental of a calibrated Laser Particle Counter with a pressure diffuser designed for sampling compressed air/gas.
SHADED area indicates 0.1 – 0.5 micron particle range in Class 2 must be analyzed using an onsite laser particle counter. *Trace Analytics, LLC provides rental of a calibrated Laser Particle Counter with a pressure diffuser designed for sampling compressed air/gas.
Trace Analytics has several compressed air testing kits available to meet your needs.