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Products and services

Humidity and moisture measurements

Calibration and standards

We provide primary humidity standards and humidity calibrations with UKAS (ISO 17025) accreditation, for numerous hygrometer types, over a very wide range of humidity and temperature conditions. Calibrations are available in terms of relative humidity, dew point, frost point or other humidity quantities expressed as fraction, ratio or volumetric units.As well as calibrations in air near atmospheric pressure, NPL provides humidity calibrations at higher pressures and in a variety of other gases and gas mixtures.

We have expertise in carrying out measurements of moisture in materials, and in related calibrations and instrumentation. Measurements can be water-specific, or can measure all moisture (which includes other volatiles and liquids) using a combination of instruments and our in-house developed techniques.

A variety of other humidity and moisture related services are available, including detailed characterisation of instruments, and calibration of humidity-generating devices such as humidity generators and humidity calibration systems based on salts or other reference materials. We also offer humidity training, design and build of humidity generators, and other problem-solving advice and consultancy.

Temperature and humidity consultancy

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Find out more about our expertise in this area, and how we are creating impact from science and engineering.

Case study

Better measurements of water vapour in fuel gas


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Still struggling to work out what you need? We pride ourselves on giving sound technical advice to guide you. By combining expert advice, standard tests and bespoke consultancy, you can be confident in our approach.

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