Guidance

NMO: standards calibration

Information on mass, length and volume calibration for local authorities and businesses.

Our service

NMO provides a statutory calibration service under the Weights and Measures Act 1985 on behalf of the Secretary of State, checking the accuracy of the mass, length and volume standards held by local authorities. We perform this work in purpose-built laboratories, providing a service of unrivalled quality for a competitive price.

Our service is also available to businesses.

We are accredited for mass, length and volume calibration by the United Kingdom Accreditation Service (UKAS) to the most exacting global specifications recognised internationally.

We draw on our combination of unrivalled expertise and specialist equipment to ensure a fast turnaround, in an average of 5 working days. We also supply standards, impartial advice and measurement consultancy.

Mass calibration

We perform mass calibration to OIML R111. The accuracy of our comprehensive service is specified in the following table. We supply and calibrate mass standards of up to 1 tonne – in stainless steel or other materials such as cast iron – to your own specification if required.

Range of nominal mass Uncertainty Class
0.05 mg - 50 kg Better than E1
0.05 mg - 50 kg OIML Class E1
0.05 mg - 50 kg OIML Class E2
0.05 mg - 250 kg OIML Class F1
0.05 mg - 1000 kg OIML Class E2

Length calibration

We perform length calibration on benches equipped with laser interferometers and custom-built track and carriage systems. Flexible line standards of up to 50 metres can be calibrated with uncertainties of (10 + 0.6 L) micrometres, a level of accuracy amongst the best in the world. (Longer lengths can be measured using multiples of 50 metres.) Rigid line standards of up to 2.3 metres can be calibrated with uncertainties of (1 + 1 L) micrometres. We supply a wide range of length standards from a variety of manufacturers.

Volume calibration

We perform gravimetric volume calibration (inferring volume from the weight of liquid discharged or contained) over a range of 1 ml to 20 litres for glassware and 1 litre to 500 litres for metal measures, with a best measurement capability of 0.008% of volume. For larger vessels we offer an on-site service. We can also calibrate volumetrically (using the transfer of liquid from a delivery vessel).

Published 3 April 2014