Products & Services
NPL can accurately generate and measure humidity through a very wide range. We provide calibrations of most types of hygrometers and humidity generators. Air temperature measurement and calibration is also covered.
A mobile service is available for calibrations and measurements at customers' sites, for example characterising climatic chambers.
We give free technical advice on humidity measurement, and can offer more detailed consultancy. We can design or supply facilities for humidity calibration.
The following measurement and consultancy services can be found at Humidity measurement services:
- Dew point
- Relative humidity and temperature sensors in air
- Mixing ratio
- Mobile calibration service
- Humidity consultancy
Other resources
For further information, please contact Stephanie Bell or Mark Stevens.
Products & Services
- NPL calibrates air temperature sensors - both those incorporated within relative humidity instruments, and thermometers used purely for air temperature measurement.
- NPL can calibrate dew-point measuring hygrometers against an NPL primary standard or a transfer standard in the range -90 °C to +90 °C.
- NPL provides dew-point calibrations at a range of pressures up to 1 MPa (10 bar), and facilities are in further development for humidity calibrations at higher pressures and in a range of gases.
- NPL offers a mobile service to calibrate or characterise the temperature and humidity performance of climatic chambers.
- Calibrations can be provided for capsules, ampoules or other suitable artefacts that use salt solutions or other chemical substances to generate stable values of humidity.
- NPL calibrates humidity generators by comparison against transfer standards, or directly against NPL's own primary standard generators.
- A two day course on humidity measurement and calibration covering dew point, relative humidity and many other humidity quantities, it will concentrate on methods of measurement which are of greatest technological relevance to attendees.
- NPL can calibrate humidity instrumentation of practically all types, including relative humidity sensors, dew-point hygrometers, psychrometers, spectrometers, humidity generators, climatic chambers and others.
- NPL has established a facility for studying the moisture content of materials, now available for measurement services, consultancies and instrument assessments.
- Relative humidity is derived from dew point and air temperature. NPL's standards and calibration service span a range from 2 %rh to 98 %rh at air temperatures from –40 °C to +100 °C.
- NPL frost-point standards and services extend well into the trace moisture range below 1 mmol/mol (i.e. below 1 ppm corresponding nominally to frost points below –75 °C).