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Thread: Temperature screening

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    Temperature screening

    Trial run using the thermal imager ...reading from 33C - 40 C... those kind of temperatures ...there should be dead people (thank goodness it was just a test run).

    It seems many companies have gone out and "invested" in a spot meter to screen staff and/or visitors.

    A few tips:

    Human body core temperature should be around 36.1-37.1 C.

    About 3 C can be added to the surface skin measurement to get an average core temperature.

    Measuring the centre of the forehead ("surface skin temperature" ...not core temperature) reading should be around 33 C - 33.5 C.

    Measuring the e tear duct or inner ear should read around 35 - 36 degrees C

    37.3 C "core temp" (not the same as surface temperature) is regarded as a low level grade fever and the person should stay home...this measurement should be done using the correct procedure.
    Last edited by ians; 05-May-20 at 09:29 AM.
    Comments are based on opinion...not always facts....that's why people use an alias.

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    If the spot meter has an emissivity setting... it should be set to 0.97 - 0.98 (for surface skin testing)

    Core temperature is about 3 C higher than surface skin temperature... you could set the emissivity to round 0.78 to offset the 3 C difference.

    There is no test available for a person during the incubation period... which is why it is recommended that if you travel from a high risk area or come into contact with people who are infected with the virus ...you should self isolate for at least 14 days.

    IF THE UNIT HAS A LASER...DO NOT POINT THE LASER AT PEOPLE...RATHER COVER IT OR SWITCH IT OFF.
    Last edited by ians; 05-May-20 at 09:36 AM.
    Comments are based on opinion...not always facts....that's why people use an alias.

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    One of the tricks when using these "forehead ir thermometers" is to make sure you are measuring over the temporal artery rather than in the centre of the forehead.

    Click image for larger version. 

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    Even with the fairly cheap and simple one I have managed to lay my hands on, there is a setting that sets the device was designed for (body temperature measurement over the temporal artery), and one for measuring objects. According to the paperwork, what this does is adjust the emissivity setting - 0.97 for the human forehead and 0.95 otherwise.

    When it comes to compensating for ambient temperature, apparently the fancier forehead thermometers measure the ambient temperature at the same time they're taking the ir reading and adjust the result accordingly for greater accuracy. The other factor that can throw an accurate reading off is very recent physical exertion.

    I liked the advice in the paperwork - the most reliable results are obtained when the individual has been at rest in a room at a reasonable ambient temperature for 30 minutes. The paperwork also claims an accuracy of +/- 0.3 degrees C, which I find pretty impressive for the money.

    I gently suggest if you are getting a wild reading, either under or over - have the person quietly seated in a room for 10 minutes or so and check again.

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    From the research i did ... a quality thermal imager requires a 0.78 emissivity to "offset" the 3 degrees difference between core and surface temperature of the human body.

    The measurements i took (thermal imager) ...33.2C-33.8C at 0.98 centre of the forehead were about right if you add 3 C ...when taken using one of those cheapie testers most people are using 36.2 C ... I havent tried changing the emissivity to 0.78 yet .
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    Quote Originally Posted by ians View Post
    The measurements i took (thermal imager) ...33.2C-33.8C at 0.98 centre of the forehead were about right if you add 3 C ...when taken using one of those cheapie testers most people are using 36.2 C ...
    The question is why is that happening? 36.2 C is what should be expected so it is your thermal imager that is producing the unexpected result.

    I have just gone over this morning's results. The range is 36.1 to 36.4 with one outlier of 35.3 C.
    Unfortunately the IR camera is not at the office for me to cross-check vs a classic imager.

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