Why is calibration of a thermometer important

The distilled mercury condenses in the upper limits of the thermometer — and accordingly the temperature indicated by the instrument is somewhat lower than the actual temperature. This problem may be undetected by the casual observer — but will be noticed and rectified by a competent calibrator.

It is not unusual for a thermometer to be damaged from accidental or unintentional overheating, or from sudden, unintentional rapid cooling. We have had, on rare occasions, thermometers submitted for a periodic re-calibration which at first examination appeared in excellent condition, but did not function properly; an examination under the microscope revealed a nearly invisible stress crack in the bulb through which a quantity of mercury had escaped — changing the reading of the thermometer in excess of 10 degrees C!

We have caught many hydrometers actually, in most cases these were thermo-hydrometers, with a thermometer incorporated in the lower portion of the hydrometer , submitted for routine re-calibration, which had suffered stress cracks from rough handling, allowing a quantity of the test liquid to infiltrate into the instrument, changing the weight mass and thus the readings of the instrument. By how much?

These are a few of the problems which many laboratory people will miss in the press of day-to-day activities. We, on the other hand, earn our living working with these instruments, and you pay us to spot easily overlooked problems which may affect the correct function of your thermometer or hydrometer, and in turn, the integrity of your data.

Re-calibration at regular intervals permits the user to see the magnitude of the changes taking place, and whether or not those changes affect the level of precision desired. Evaluation of the changes observed throughout a series of recalibrations permits the user to set forecasts based on historical data and thereby determine appropriate calibration intervals for the future.

Why is it necessary to have my calibrated thermometer or hydrometer re-calibrated? Save my name, email, and website in this browser for the next time I comment. Kasy Allen is the owner and lead marketing strategist of Annapurna Digital , a digital marketing agency. In addition to working with Tundra Restaurant Supply with their online marketing strategies, Kasy has helped many online brands find their online voice and an online marketing strategy that brings in the right users and increased revenue.

When not in the office, Kasy can be found exploring the great outdoors of the Colorado Rocky Mountains. From their requirements and the environmental conditions, the verification of the measuring instruments is also derived. The calibration of temperature measuring instruments makes sense and is necessary for a variety of reasons.

Firstly, the calibration of thermometers, such as thermocouples, is gaining in importance in the context of scarcity of resources and increasing the efficiency of manufacturing processes. An increase in measurement accuracy can result, for example, not only in raw material savings, but also in fewer pollutant emissions. Secondly, the calibration of thermometers can be relevant to safety. If measuring instruments in the chemical industry, for example, do not supply the correct values and if they result in faulty control of chemical processes, a risk of explosion may arise.

The importance of calibration is also evident in everyday examples if one thinks, for example, of meters for gas and water consumption in the home or the fuel meters on service station fuel pumps.

It is therefore obvious that a regular calibration of thermocouples or resistance thermometers is necessary in order to re-confirm the confidence in the measured value or to determine any change over time.

If in doubt, the thermometer can be readjusted or replaced before the process is damaged. Calibrating temperature measuring instruments is an expense that many companies cannot or will not afford on their own.

This is especially true for processes that are certified in accordance with ISO and comparable quality assurance systems. QA systems require a regular check of the measuring instruments, which must be traceable at the same time.

To this standard, the display of a measuring instrument used or a material measure is compared. This can be done in one or more stages. At each of these stages, a calibration is performed on a standard previously calibrated with a higher-ranking standard. The standards are subject to a defined ranking. These range from working or factory standards to reference standards and national standards.