Temperature is a critical measurement for ensuring the safety and quality of many products. Whether monitoring temperature at the point of goods in, throughout production, final product storage or during distribution, thermometer calibration is essential.

The food industry, in particular, is very aware of the critical nature of processing temperatures as part of their HACCP procedures. The importance of thermometer calibration is not just a food safety issue, but also an economic consideration, as thermometer accuracy can affect both quality and productivity.

It is recommended that thermometers and temperature monitoring equipment be calibrated regularly. New equipment should be checked for accuracy upon receipt and before being put into service. Thermometers that are in constant use and used in critical areas should be calibrated more regularly. The definition of a regular calibration check is very much at the discretion of the user, for example, a food processing company may well decide to check thermometers daily before use, whereas a restaurant may decide that once a week is adequate.

calibration checks
Depending on the instrument and its intended temperature and use, an iced water and boiling water method can be used for checking the accuracy of a thermometer and probe. When used properly and in conjunction with a Reference thermometer, this offers a cost-effective method of calibrationand verification.

Other techniques can be employed utilising dry-well and calibration baths in conjunction with a Reference thermometer. These techniques are particularly relevant and often more convenient when several thermometers and temperature
probes are to be calibrated at any one time. Dry-wells and calibration baths provide variable and stable heat sources.

A Reference thermometer is a particularly important instrument for checking the calibration of other thermometers and probes. However, it is of paramount importance

that this instrument is kept for the sole purpose of verifying the accuracy of thermometers and temperature probes and has a current UKAS Certificate of Calibration.

Temperature simulators are an alternative to real-world temperature checking and are particularly useful for checking thermometers on-site or in-situ. It should be remembered, when using temperature simulators, that you are only checking the calibration of the instrument and not the system.

UKAS Certificates of Calibration
ETI's in-house UKAS calibration laboratory offers certification for both thermometers and probes either individually or as a system. Each UKAS Certificate of Calibration indicates deviations from standards at five temperature check points.