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Temperature measurements

Optical combustion thermometers

From 2040 K to 2260 K

World-leading, portable flame for on-site calibrations

We have a world-leading facility, which comprises of a portable, and extremely reproducible, flame for comparison calibrations at the customer’s site. The NPL standard flame provides a reproducible region of high temperature gas of known temperature and composition. It can be used for the calibration of optical thermometry techniques commonly found in combustion research.

The flame is initially calibrated using laser Rayleigh scattering and this provides traceability to the ITS-90. The complete system is portable and following delivery, providing you have a suitable fume extract, can be up and running in as little as three hours. The system is currently configured to operate with industrial grade propane and compressed air, both of which can be provided by NPL, if required.


By adjusting the equivalence ratio (φ), the flame temperature can be fixed at any temperature from 2040 K to 2260 K and for each φ, details of the gas composition can be provided.

The uncertainty in the flame temperature is 0.45 % of the temperature.

The long term reproducibility of the flame temperature is better than 0.20 %.

Don’t see what you are looking for? Our diverse skill set enables us to provide bespoke solutions. Please contact us to discuss your requirements.

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