Calibration Services

A calibration is a procedure in which an instrument is tested to make sure it conforms to a recognised standard and is used to verify the accuracy of an instrument.

It is the process of checking, by comparison with a standard, the accuracy of a measuring instrument and provides accurate corrections which can be applied to the readings obtained in use.

• By comparing an instrument of a known value against a second instrument (unit under test), the difference can be calculated, and suitable corrections determined.
• A calibration provides the user with confidence that the instrument they are using works correctly.
• Without periodic calibration, an instrument can drift out of the manufactures specification unrecognised and lead to incorrect test results.

We are able to calibrate the vast majority of products we sell, as well as calibrating your own instrument. If you have any doubt about whether or not your instrument is suitable for calibration, please contact our sales team on 01946 816 600 or sales@brannan.co.uk.

When buying a new instrument, the point of interest should be between the centre and the ¾ mark of the scale.

If for example a pressure gauge is required to measure a line pressure of 10 bar, a 0-10 bar gauge will be able to make the measurement, but a 0-16 bar gauge will give arguably more accurate readings and will be less likely to suffer from small pressure spikes and over pressure issues.

UKAS (United Kingdom Accreditation Service) is the sole body recognised by HM Government for assessing and accrediting the competence of calibration and testing laboratories to (BS) EN ISO/IEC 17025:2017 – ‘General requirements for the competence of testing and calibration laboratories’.

We have been accredited by UKAS (0582) to perform calibrations relating to temperature instruments.

Our calibration lab has been assessed against internationally recognised standards to demonstrate our competence, quality, and performance capability.

Traceable calibrations are conducted according to similar standards, which ensure the results are correct; however an official governing body such as UKAS does not approve the results and uncertainties are not stated.

All our traceable calibrations are traceable to national standards and the process is carried out following documented procedures.

We recommend getting your instrument calibrated yearly, however the frequency for a specific instrument is up to the individual customer. It should be based on:

• The environment in which the instrument is used,
• The frequency of use,
• Any evidence of changes or trends in calibration data and the level of confidence required in the readings.

The customer must decide what is the consequence of an incorrect reading?

• If you waste a batch of wine due to an incorrect temperature reading, the consequences are probably far less than if you are performing a scientific experiment to formulate a new drug.

Has the device been subjected to any misuse or obvious damage? If the thermometer is used out on site it is perhaps more likely to become damaged or knocked than if were kept in a cupboard in the laboratory between use.

Calibration points can be drawn on a graph and joined together to form a curve. This therefore allows the user to estimate the corrections at points where a calibration value has not been measured.

• More calibration points will reduce estimation errors, but each calibration point chosen will incur a cost, so the number chosen will be a trade-off between accuracy and cost.

It is preferable for the customer to consider what points the calibration should be carried out at and specify these at the time of request. Calibration points should either be:

• Specific to your process, such as -18°C, 0°C and 4°C for fridges and freezers
• Or cover a minimum of 80% of the range of instrument if it is for general purpose use. For example a -10°C to 110°C thermometer can easily be calibrated at 0°C, 50°C and 100°C.

The number of points checked will again be determined by the intended application. If the thermometer is used to check a single point (e.g. 10°C), then only that point need be checked. However, it may be preferred to select a small range around a point (e.g. 9°, 10° & 11°C).

Our standard calibrations offer a 5 point calibration across a minimum of 80% of the instruments range.

Brannan strongly recommends that you calibrate your instrument at a minimum of 2 temperature points. This allows the calibration to be valid across the range of 2 temperatures and a calibration curve can be plotted. If the instrument is calibrated at only 1 temperature point, the calibration is only valid at this exact point. For example if the calibration is carried out at only 10°C, it will not be valid at 9.9°C or 10.1°C. If you insist on having a 1 point calibration, please confirm you are aware that this will be marked as a limited calibration. The certificate and calibration will be marked with the words LIMITED CALIBRATION.

Through the International Laboratory Accreditation Cooperation (ILAC) agreement our UKAS accredited calibrations are to the same international standard that NIST calibrations are performed. Although we cannot issue a NIST certificate our UKAS certificates are to the same standard, only using the UK alternative.

The ILAC agreement ensures our UKAS calibration (0582) certificates are recognised around the world.

Yes, all of our certificates are stored electronically and can be retrieved for a small charge should the customer need a replacement. Please contact our sales team for more information on 01946 816 600 or sales@brannan.co.uk. Please have the serial number of the instrument and/or certificate number available.

UKAS accreditation requires that estimates of the maximum errors during the calibration are displayed on the certificate.

Uncertainty of measurement is the doubt that exists from the result of the calibration. People assume that well made instruments should be trustworthy and give correct answers, but for every measurement there is always a margin of error.

The uncertainty of measurement on our UKAS calibration certificates arises from many different factors such as uncertainties with our calibration equipment, materials used, and environmental conditions.

UKAS certificates state the maximum probable uncertainty associated with all aspects of a calibration with a confidence level of 95%. These uncertainties are quoted on UKAS certificates and can be used as part of the uncertainty budget for your measuring system.

We aim to turn calibration instruments around within 7 business days from receipt, providing we have all the information we require. Exceptions to this are orders where a large number of calibrations are needed.

Please contact our sales team for more accurate turnaround times based on the current lab workload.

All items requiring calibration should be shipped to the following address along with a copy of the purchase order or similar documents allowing us to identify your instrument:

S. Brannan & Sons Ltd
Leconfield Industrial Estate
Cleator Moor
Cumbria, England
CA25 5QE

Please ensure that your instrument is adequately packed with sufficient protection to prevent damage during transit.

Please include a copy of the purchase order in the packaging or similar documents, allowing us to identify your instrument.