What is compressed air cleanliness?
Compressed air cleanliness refers to the levels of solid particles, moisture, oil, and other contaminants present in compressed air. Cleanliness directly affects the service life of pneumatic equipment, product yield, and process safety, particularly in industries such as food, pharmaceuticals, electronics, and precision manufacturing, where air quality requirements are extremely stringent.
International standard: ISO ISO 8573
ISO ISO 8573 is a globally recognized standard for classifying compressed air quality, divided into three core parts:
- ISO ISO 8573‑1: specifies the cleanliness classes for compressed air, grading based on three primary contaminants—particulates, water, and oil (e.g., Class 1.1.1);
- ISO ISO 8573‑2 through ‑9: cover specific test methods, including particle counting, dew point measurement, and oil vapor detection;
- For each contaminant, clear limits are set based on concentration or content; the lower the class number, the higher the cleanliness.
Key Contaminants and Control Measures
•Solid Particles: affect valve response and sensor accuracy and must be controlled through multi-stage filtration (pre-filtration, main filtration, and fine filtration);
•Moisture: expressed in terms of pressure dew point (PDP), achieved using refrigerated or desiccant dryers;
•Oil: includes oil mist, oil vapor, and liquid oil, requiring combined treatment with oil removal filters and oil-free compression technology.
How can compliance with cleanliness standards be achieved?
Achieving compliance requires a systematic approach: select the appropriate compressor type (oil-lubricated or oil-free), configure matching downstream air‑processing equipment, regularly verify filter performance, conduct periodic air‑quality monitoring, and maintain comprehensive operation and maintenance records. Relying on a single piece of equipment alone cannot meet the stringent requirements of higher cleanliness classes.