What dew point tells you
Pressure dew point is the temperature at which moisture starts to condense from compressed air at line pressure. It matters because liquid water in the system causes corrosion, damages tools and instruments and can spoil products and processes.
Why a display is not enough
A dryer controller reading can differ from the real condition because:
- The sensor is located inside the dryer, not at the point of use
- The sensor may be out of calibration or fouled
- Moisture can enter after the dryer through leaks or poor piping
- The dryer may be overloaded at peak flow or high inlet temperature
How we measure
Good sampling practice includes:
- Choosing the sample point to represent the air the process receives
- Using a calibrated dew-point instrument suited to the expected range
- Sampling at line pressure or correcting properly to it
- Allowing the reading to stabilise and avoiding contamination and leaks in the sample line
- Recording the pressure, temperature, flow and date with the result
Interpreting the result
The result is compared with the dew point the process needs, with margin for changes in ambient temperature and load. A good reading at one time does not prove it stays good, so trends and repeat checks matter.
What you receive
A record of each sample point, the method and instrument, the reading and conditions, and a clear statement of whether the air meets the stated requirement, with recommended actions if it does not.
Start with
To arrange the work, please share:
- A simple layout or description of the compressor room, treatment and main piping
- Compressor and dryer details and operating pressure settings
- Operating hours, shift pattern and the problem you are seeing
- Any existing readings, trends or previous audit reports
Frequently asked questions
What dew point do I need?
It depends on the application and local conditions. Instrument air, painting and food contact usually need drier air than general workshop use. We help you define the requirement.
Can I rely on my dryer display?
It is a useful indicator, but independent measurement at the point of use is the evidence.
Does dew point measure oil or particles?
No. Water vapour is one part of air quality. Particles and oil need their own measurement.