• Make sure the thermometer has a reset button. This video demonstrates two methods for calibrating a digital thermometer: first, with ice and boiling water, and second, with our Fluke dry-block calibrators. You may have the ability to undertake this adjustment in-house or you may need to send the equipment to an external calibration provider. Insert the thermometer’s stem a minimum of 2” into the water for a few minutes, taking care to not burn you while doing this. As an example, I used an IR thermometer to measure my own forehead temperature and it gave me a really low reading. Whether you can use infrared thermometers on  humans depends on the type of thermometer being used. Use a National Institute of Standards and Technology (NIST) certified thermometer for testing thermometer … People have also asked about fever scanning systems. The thermal imager thinks that the left side of the plate is much colder than the right side. Calibrating Your Thermometer. If the thermometer doesn’t have the adjusted mode, it’s designed for industrial thermometry applications with a wide temperature range. Infrared thermometers for measuring ear canal temperature have an even tighter requirement of ± 0.2 °C (±0.36 °F). That is mainly because this wavelength band is not as sensitive to humidity and it provides enough energy to be detected reliably. Measuring with an IR thermometer is an optical measurement, so just like binoculars and telescopes there is a field of view. How do you calibrate a digital thermometer? To calibrate an adjustable digital thermometer: For all thermometers: • Non-adjustable digital thermometers may be accuracy checked, even if they can’t be adjusted by the user. If it does not, you cannot recalibrate the thermometer. Add a little clean water until the glass is full and stir. ASTM requires that if you are going to use an IR thermometer for measuring skin temperature, it must be accurate to within ± 0.3 °C (±0.54 °F). The frequency of calibration depends on several factors. It may be a good idea to move the IR thermometer closer and further from the target by a few cm to verify readings do not change due to a change in distance. Wait for about three minutes before inserting the sensor on the thermometer into the ice-filled water. Thermometers must be calibrated because they tend to lose their calibration when handled constantly. Generally speaking, people consider skin to have an emissivity of 0.98 but ASTM points out that can vary from 0.94 to 0.99. For digital thermometers, you only need to click the reset button for you to calibrate it again. For digital thermometers it should be a bit of an easier process, since there is usually a reset or calibrate button with these thermometers that allows you to recalibrate. A more complicated low-uncertainty method using a reference thermometer will be described in detail in future articles and application notes along with advice for calculating measurement uncertainty. With this non-contact method measurement uncertainty is on the order of 0.5 °C (0.9 °F), but it is much simpler. We’re also working on more technical content which will be published at a later date. The infrared light, or energy, passes through the atmosphere and goes into the IR thermometer’s optics. This is a simple calibration procedure designed to calibrate your IR thermometer at the Zero Deg C range only. Although the entire plate is at the same temperature, the thermal imager is tricked because of the emissivity issue. Use ASTME 1965-98 as a platform to base your knowledge on and see what the expectations are for these instruments. 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