Air Quality Specifications

The tables below show the compressed air specifications as outlined by the BCAS and ISO 8573:2010. Many manufacturers establishing SOPs for compressed air used in the manufacturing process refer to these specifications to help establish their own guidelines.

BCAS Food and Beverage Grade Compressed Air
Best Practice Guideline 102

ISO 8573-1:2010
Purity Class
Particles (P) Water Oil
By Particle Size
(maximum number of particles per m3)
Vapor Pressure Dewpoint Aerosol & Vapor
0.1 - 0.5 micron 0.5 - 1.0 micron 1.0 - 5.0 micron °C °F mg/m3
Direct Contact
2:2:1
400,000 6,000 100 ≤ -40 ≤ -40 ≤ 0.01
Indirect Contact
2:4:2
400,000 6,000 100 ≤ +3 ≤ +37 ≤ 0.1
Microbial Contaminants Hazard analysis shall establish the risk of contamination by microbiological contaminants from compressed air. The level of control identified as being required over microbiological contaminants in the compressed air shall be detected using the test method specified in ISO 8573-7.
Footnotes (P) Particle classes 1-5 may not be employed if particles >5 micron are present according to ISO 8573-1.
Air & Gas Specifications referenced above may be viewed and/or purchased from: BCAS - British Compressed Air Society

ISO 8573-1:2010 Compressed Air Contaminants and Purity Classes

Class Particles Water Oil
By Particle Size
(maximum number of particles per m3) See Note 2
By Mass Vapor Pressure Dewpoint Liquid Liquid, Aerosol, & Vapor
See Note 1
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 -
8 - - - - - - ≤ 5 -
9 - - - - - - ≤ 10 -
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 in the range of C1 to C5

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.

Air & Gas Specifications referenced above may be viewed and/or purchased from: ANSI - American National Standards Institute
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