What is the water content standard for industrial compressed air?
The water content standard for industrial compressed air varies according to the use scenarios and industry requirements, mainly throughdew point temperatureandwater vapor content(ppmv, parts per million of volume). The following are specific standards and descriptions:
1. National standards (GB/T 13277.1-2023)
According to the level of moisture content in compressed air, national standards divide compressed air into 6 levels. The lower the dew point temperature, the higher the degree of dryness:
| level | dew point temperature | Water vapor content (ppmv) | applicable scenarios |
|---|---|---|---|
| Grade 1 | ≤-70℃ | ≤2.598 | Very high purity needs (e.g. electronic chip manufacturing) |
| Grade 2 | ≤-40℃ | ≤127.34 | High-precision industries (such as pharmaceutical production, laboratories) |
| Grade 3 | ≤-20℃ | ≤1024.22 | Conventional industries (such as machinery manufacturing, chemical industry) |
| Grade 4 | ≤+3℃ | ≤7537 | General industries (e.g. construction, mining) |
| Level 5 | ≤+7℃ | ≤9987 | Non-critical applications (such as general pneumatic tools) |
| level 6 | ≤+10℃ | ≤12267 | Low-requirement scenarios (such as cleaning, dust removal) |
2. Industry standards
- Highly demanding industries(Such as automotive spraying, food and beverage, semiconductors):
- moisture content: Usually required to controlBelow 10ppm(That is, no more than 10 mg of water per cubic meter of gas).
- dew point temperature: Need to achieveBelow-40℃。
- general industrial(such as construction, building materials, metallurgy):
- moisture content: Usually controlled inBelow 50ppm。
- dew point temperature: Requirements are+3℃ to +7℃。
3. International common standard (ISO 8573-1)
In the compressed air standard developed by the International Organization for Standardization (ISO), measurementWater, oil, particulate matterThree pollutants are classified into grades. For moisture content, the requirements are similar to the above-mentioned national standards, but will be further refined based on specific industries (such as medical and electronics).
4. Water content testing methods
- dew point method：
- By cooling the compressed air to condense water vapor, the dew point temperature is measured with the highest accuracy.
- capacitive sensor method：
- Water content is detected by air capacitance change, which is suitable for on-line monitoring.
- chemical method：
- It is easy to judge the moisture content by the color change of reagent reaction, but the accuracy is low.
5. Key factors affecting water content
- ambient humidity：
- Dry treatment needs to be strengthened in humid climates or seasons.
- cooling system：
- The efficiency of the cooler affects the condensate separation effect.
- drainage system：
- Blocked automatic drain valves can cause moisture to remain.
- drying equipment：
- The performance of the adsorption dryer or freeze dryer directly affects the final water content.
6. Suggestions on handling exceeding standards
If the water content in the compressed air exceeds the standard, the following measures can be taken:
- boosts efficiencydrying equipment(Such as adsorption dryers).
- regular cleaningcooleranddrainage system。
- Increase in key linksprecision filterPerform secondary drying.
- Monitor environmental humidity, and inspect the air compressor room if necessarydehumidifying process。
When selecting an air compressor and configuring drying equipment, you need to refer to the above standards according to actual needs and consult the equipment supplier to match the best solution.