Are air compressors with oil content less than 0.01ppm oil-free air compressors?
Professional instructions on the technical attributes of air compressors with oil content less than 0.01ppm
After systematic study of international standards and industry specifications, the relationship between oil content indicators and the technical definition of oil-free air compressors is explained as follows:
1. Technical standards for oil-free air compressors
According to the International Organization for Standardization ISO 8573-1 “Compressed Air Part 1: Pollutants and Purity Grades”, oil-free compressed air must meet Class 0 standards, and its core indicator is the total oil content (including liquid oil, mist oil, gaseous oil) is less than 0.01mg/m³. After unit conversion, the corresponding volume concentration of this indicator is about 0.008ppm, which is significantly lower than the 0.01ppm threshold mentioned by users.
2. Technology realization path
Achieving Class 0 standards requires dual technical guarantees:
- Structural design: Dry screw technology (no lubricating medium between rotors) or water lubrication technology (purified water is used instead of lubricating oil) is adopted to prevent oil from being mixed in from the source
- Purification system: Equipped with a three-stage precision filtration device (filtration accuracy reaches 1μm, 0.01μm, and 0.003μm in turn), combined with coagulation filtration technology, it can remove 99.999% of residual oil
3. Testing and certification requirements
Equipment that meets oil-free standards must pass the full flow test method (ISO 8573-1 B1 test method), which has the following characteristics:
- Detection range: Covering the entire airflow cross-section, it can simultaneously identify mist oil (0.01-1μm) and liquid oil (>1μm)
- Detection accuracy: It can detect oil concentrations as low as 0.003mg/m³
- Certification body: Test reports must be issued by TÜV, SGS and other third-party testing agencies
4. Additional requirements for special industries
In regulated fields such as medical care and food, in addition to oil content indicators, it is also necessary to meet:
- Microbial control: compressed air needs to pass the plankton test (≤10CFU/m³)
- Particulate matter control: Concentration of particulate matter above 0.1μm ≤1000 pieces/m³
- Humidity control: pressure dew point ≤-40℃ (corresponding water content ≤67mg/m³)
5. Description of technical boundaries
Air compressors with oil content <0.01ppm are close to oil-free technical requirements in terms of concentration indicators, but attention should be paid to:
- Differences in detection methods: If only partial flow detection method (B2 test method) is used, oil content attached to the pipe wall may be missed
- System integrity: It is necessary to confirm whether the equipment is equipped with terminal filtering device and automatic drainage system
- Scope of certification: Some models may only pass individual tests under certain operating conditions
It is recommended that users give priority to equipment that has passed ISO 8573-1 Class 0 certification when selecting models, and require suppliers to provide complete certification documents including testing methods, environmental conditions, and equipment configuration. For high-demand scenarios such as medical and food, it is recommended to add regular third-party testing clauses to ensure that the quality of compressed air continues to meet regulatory requirements.
