Humidity metrology

Humidity is an important factor for the quality of many processes. Too much or too little humidity can cause mould, damage or corrosion and lead to the formation of hydrates. It can also result in human discomfort. All this can be avoided by carrying out regular humidity measurements that are reliable and, above all, traceable.



Humidity is an important factor for the quality of many processes. In the production of medicines and food, for example, humidity needs continuous close monitoring to ensure quality. At worst, excess humidity can cause bacteria and mould to develop.

In the natural gas industry, humidity is a particularly important factor in preventing damage. Water vapour in pipes produces corrosion and when combined with methane, hydrates can form, leading to blockages in the flow of gas and damage to pipes.

Humidity also has an effect on human comfort. A room that is too damp is unpleasant and it can also cause mould. A room that is too dry is just as unpleasant, resulting in headaches and irritated eyes. Dry air also reduces our natural immunity, making us more susceptible to infections.

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Michel Brakel
Sales Engineer

VSL and humidity

VSL provides various traceable humidity measurement services for clients including the food, pharmaceutical and process industries, and accredited calibration laboratories.

The national primary reference standard for humidity is a primary humidity generator. It conditions a gas flow to be completely saturated with water vapour at temperature and pressure levels that are accurately determined. The gases used are air, nitrogen and methane. The reference standard is directly traceable to the SI units.


We provide support and advice on issues from manufacturers and end users, enabling them to improve measurement and inspection methods to optimize process and product quality. is directly traceable to the SI units.


Custom humidity metrology

VSL has extensive knowledge of measurements and the interpretation of humidity measurement data. We provide the following and other services:

  • Development of and advice on humidity measurement methods.
  • Validation of humidity measurement systems.
  • Preparing and reducing uncertainty budgets.
  • Guidance on setting up and accrediting quality systems.

Every situation is unique. Do you need advice or would you like to know what we can do for you? Don’t hesitate to contact us.


Humidity calibration services

Humidity is important for improving products, reducing costs and raising human comfort levels. Together with temperature, it often plays a role, whether direct or indirect, in various processes, such as in the petrochemical industry, energy production, health care and environmental issues. By measuring humidity accurately, VSL can help minimise its negative impact on many processes and products. We also provide humidity measurement services to sensor manufacturers and calibration laboratories.

Calibration of dew point meters

VSL calibrates dew point meters against the primary humidity generator and humidity sensors. We do this in a climatic chamber containing a primary-calibrated dew point meter and temperature sensors. This entire calibration process, including the analysis of results, uncertainty calculations and creating certificates, is automated. As a result, turnaround times are short.

Our areas of expertise