01
Pressure dew point is not ambient relative humidity
Compression changes the partial pressure of water vapour, and cooling compressed air can create liquid condensate even when the intake air did not appear unusually humid. A dew-point value is incomplete unless its pressure basis and measurement location are stated.
02
Match the dryer to the coldest part of the system
Indoor plant air may tolerate a refrigerated dryer target, while outdoor winter pipework, instrument air, painting, electronics, or sensitive processes can require a much lower pressure dew point. Measure or specify at a point representative of the delivered air after treatment and distribution losses.
03
Dryness is only one part of air quality
ISO 8573-1 purity notation separately addresses particles, water, and oil. A low pressure dew point does not prove low particle or oil content, and a fine filter does not dry the air. State all required purity positions and the measurement point.
Selection checklist
What to verify before selection
- 01
Lowest ambient and pipe temperature
- 02
Operating pressure at the stated dew point
- 03
Peak flow and dryer inlet condition
- 04
Required ISO 8573-1 water class
- 05
Measurement point and sensor method
- 06
Pressure loss, purge demand, and maintenance
Application caution
Common mistakes
- Comparing pressure dew point with atmospheric dew point without conversion
- Specifying dryer type without peak inlet conditions
- Treating a water-class result as a complete air-purity specification
FAQ