Core Standards System
Compressed air used in the food industry must meet stringent cleanliness requirements. The internationally recognized standard isISO 8573-1:2010It specifies the grading methods for the three major contaminants in compressed air: particulates, water, and oil. China has adopted this standard on an equivalent basis and issued it.GB/T 13277.1, serving as the technical basis for assessing the quality of compressed air used in food processing.
Classification of Cleanroom Grades
According to ISO 8573-1:2010, compressed air cleanliness is classified into grades based on three categories of parameters:
- Solid particles: Based on the maximum permissible particle size and count (e.g., Class 1 requires ≥0.1 μm particles ≤20 per …). m³);
- Moisture: Expressed as the pressure dew point temperature (e.g., Class 2 requires a pressure dew point ≤− 40 ℃）；
- Oil content: includes the total of oil vapor, oil mist, and liquid oil (e.g., Class 1 limit ≤ 0.01 mg/). m³）。
Microbial Control Requirements
Food-grade compressed air requires particular attention to the risk of microbial contamination. Although ISO 8573‑1 does not directly specify microbial limits, the supporting technical documents for GB/T 13277.1 and industry practice generally stipulate that:The sterile air system shall be subject to periodic validation to ensure that the microbial count remains below 1 CFU/ m³Moreover, no pathogenic bacteria shall be detected. The selection of filters, the drying process, and the materials used for piping must all support this objective.