The importance of dew point measurement in compressed air dryers

Compressed air is vital across industry, powering automation, pneumatic tools and countless production processes. Yet even trace moisture can undermine system integrity, damage equipment and contaminate products. The most effective control is accurate dew point measurement—giving real-time insight into air quality and dryer performance.

Compressed air dryers
Dryers remove water vapour, but performance varies with operating conditions and maintenance. Typical capability by technology:

• Refrigerated dryers: dew points around +3 °C to +10 °C.

• Desiccant dryers: down to −40 °C to −70 °C for critical duties.

• Membrane and deliquescent dryers: options for specific applications.

Whatever the technology, only continuous monitoring with dew point transmitters confirms the system is delivering the required dryness.

Why dew point measurement matters
Dew point is the temperature at which air becomes saturated and condensation begins. Monitoring it is essential to:

• Verify dryer efficiency.

• Detect faults early.

• Demonstrate compliance with standards such as ISO 8573-1 for compressed air purity.

Without this data, moisture-related failures can go unnoticed, leading to corrosion, blockages and costly downtime.

Risks of poor or absent monitoring
If dew point is not measured accurately, moisture ingress may remain undetected. In pharmaceuticals, food processing and electronics this risks contamination and product rejection. In outdoor installations, excess moisture can freeze in pipework and halt operations. Non-compliance with ISO standards also creates regulatory and quality risks.

Good practice for reliable monitoring

• Install fixed dew point sensors downstream of dryers for continuous measurement.

• Use portable instruments for periodic spot checks at key points.

• Calibrate sensors and maintain dryers regularly.

• Align with ISO 8573-1 (air purity) and ISO 7183 (dryer performance).

• Use appropriate sampling systems to ensure representative, stable readings.

Accurate dew point measurement is a critical control for compressed air systems. It confirms drying equipment is working correctly, supports compliance and minimises moisture-related failures. By prioritising precise monitoring and sound maintenance, industries can safeguard operations, protect product quality and optimise efficiency.

For more information on dew point measurement in compressed air applications, contact the Shaw team.