What is the pressure dew point?
The pressure dew point is the temperature at which water vapor in compressed air begins to condense into liquid water under a specified operating pressure. The lower this value, the less moisture the air contains, and the higher its degree of dryness.
ISO Standard 8573-1 and Grade Classification
ISO ISO 8573‑1 is the internationally recognized standard for classifying compressed air quality, defining grades based on three parameters: solid particulates, oil content, and pressure dew point. Pressure dew‑point classes are designated by numerical grades (e.g., Grade 1, Grade 2, Grade 3), with lower numbers indicating more stringent requirements.
Pressure dew point requirements for Class 2 standards
- The corresponding maximum allowable pressure dew point is +3 °C
- Suitable for industrial applications that are sensitive to humidity but do not involve extremely harsh conditions.
- Commonly found in pneumatic control systems, pre-coating treatment, and certain packaging and food-contact processes.
Commonly used equipment for achieving Level 2 standards
Refrigerated air dryers are one of the mainstream solutions for meeting Class 2 pressure dew‑point requirements. They use a refrigeration cycle to cool compressed air to near its dew‑point temperature, causing moisture to condense and separate; the condensed water is then discharged via a gas–liquid separator. Proper equipment selection and standardized maintenance are essential to ensuring consistent compliance with specifications.