IR non-contact thermometer

[dad911]

I have one for general-purpose use. Reads 95ish degrees at my forehead. Ryobi, not rated or sold for use 'on people'

I notice Amazon sells some labelled for 'people' or 'person' yet others 'Non-human' or 'for objects'

What's the difference? (All are IR, and non contact)

[masraum]

All are non-contact as far as I know.

I'm not sure about the "people" vs "not people" unless maybe there's some sort of algorithm that enables it to estimate temp on the inside from the outside.

Your skin is not, I don't believe, ever going to show 98.6*, otherwise you wouldn't have to hold a regular thermometer under your tongue or up the wazoo.

[nota]

the human ones have a narrow but precise range
others have a wider but less accurate range

[masraum]

I found this online and I suspect it touches on what I'm thinking.

Yes and no, the body measure thermometers use a bolometer that is selected to have a good response at around 35-45C, and is calibrated to be accurate with a black body radiator ( the human skin in the ear and mouth is a pretty good black body approximation) to within 0.05C. the industrial sensors are only going to have 0.5C resolution and up to 2C of error at that point.

Using them to measure also requires knowing ( or taking a guess) at emissivity of the surface, you only get an accurate temperature with a surface that is the same or similar emissivity as the one it was calibrated to. Some you can set the emissivity, but your accuracy is poorer then, and the fixed units can have a very large error.

Another quote from the 'Net.

Yes, you can. I am an architect, not medical, but did a lot of work on actual vs perceived temperature.

Set the emissivity to 0.85, this is good for a range of skin types. For individuals, say, your family, calibrate the IR thermometer. Get them to breathe through the nose for one minute, then take a reading on the back of the throat. While doing the nose breathing, take the temperature under the tongue with a mercury or digital thermometer. Write down the readings, this will give you an indication of how they might differ in the future for this particular person. If the readings are the same, great! no calculations next time. If they are not, do it three times to get an idea of how the temperatures typically diverge. You are only looking for a fever indication; it doesn’t have to be accurate. Next time, just shoot them down the back of their throat and add their typical difference.

If you just want a general, fast indication that somebody has a fever, say, as people line up to enter a workplace, aim it at the forehead not the back of the throat. This will not be so accurate but will give a good indication. Skin colours will not have a significant effect on emissivity, actually, we are all just shades of coffee. Pull any anomalies off line, retest them on the forehead then confirm with a thermometer under the tongue or refer them to medical. Take into account the weather, how much exertion was involved in joining the line, and anything they were wearing on their faces, such as a balaclava. Expect everybody’s foreheads to be reading slightly lower than under the tongue, all you are looking for are the anomalies that warrant further scrutiny.

Then there's this chart that says that skin is .95-.98
https://www.thermoworks.com/emissivity-table

This link seems to cover things pretty well too.
https://www.thermoworks.com/covid-19-screening

ThermoWorks other infrared thermometer products are intended for food service, food processing, industrial, scientific and general home use. They are not FDA Cleared for clinical use. However, in the current pandemic environment, there is a worldwide shortage of infrared sensors and medical infrared thermometers. With proper technique, general-purpose infrared thermometers might be used as a substitute scanning tool for detecting elevated body temperatures. We offer the following information and cautions:

Forehead temperature is several degrees lower than core body temperature of 98.6 F (37 C). Clinical forehead thermometers make a mathematical adjustment to display an equivalent oral temperature. When using general-purpose infrared thermometers to read forehead temperatures, the readings will likely be lower than 98.6 F, even if a fever is present. Normal forehead skin temperature can vary several degrees depending on your environment (indoors or out), exercise, perspiration, direct heat or air conditioning, etc. It would be normal to read an actual forehead skin surface temperature between 91F and 94F if using a general-purpose infrared thermometer.

Some infrared thermometers have an “adjustable emissivity feature”. Some are factory set for emissivity of 0.95, or in the case of our IRFS, 0.97. Human skin temperature is in this range. If using a fixed emissivity infrared thermometer, one could measure temperature in the center of the forehead, and then add 5 degrees Fahrenheit to estimate the oral equivalent.

Or, to simplify things for the operator, one could measure each subject and look for a “normal” temperature of 91F to 94F without making any adjustments or offsets. A higher reading might indicate a fever. Still, such a scan could not be regarded as a reliable absolute measurement of core body temperature, only a scanning or screening indication.

Users should be aware of the “spot size” of the infrared thermometer’s measurement area. They should also consider the distance-to-target recommendations of the instrument. The angle of the sensor to the subject is also important.

If the general-purpose IR thermometer has a laser-pointing feature, it is best to turn the laser off if possible (or cover it with tape) and always use great care to avoid pointing it at someone’s eyes. The laser is not part of the measurement technology and is only used to assist in aiming.

Some industrial IR thermometers allow the adjustment of the emissivity setting. In medical literature human skin is noted to have an emissivity between 0.95 and 0.99 regardless of color. By setting an adjustable emissivity to 0.78, the instrument will give a forehead temperature reading that approximates the normal oral temperature. This approximates an “offset” to the reading that will render a measurement near 98.6 F on the forehead of a healthy individual.

[Eric Coffey]

There are dual-mode ones that are pretty accurate. If you want one for "human" use, I'd look for one that is FDA approved.

[RWebb]

should be ~~ 0.95 no matter what your skin 'color'

these work off of longwave radiation (hence the IR in the name) and all humans are black in the "IR"

indeed all non-metallic objects

[sammyg2]

I have two IR thermos, one is from harbor freight ($20) and one is a fluke intrinsically safe unit ($1000).

Surprisingly they read about the same on most things. One big difference is the fluke is adjustable for emissivity.

My guess that a specialized thermo for humans is calibrated for emissivity of skin, and may have a narrow and more accurate range. Not sure about that.
Bu I'd bet if my fluke was calibrated and checked with a standard, then it would be accurate enough for the girls I run with.

[sammyg2]

BTW my harbor freight IR gun gets used most keeping the cat occupied

[RWebb]

pics of the the girls you run with

forget the cats

[sammyg2]

Didn't happen

[masraum]

Originally Posted by sammyg2

I have two IR thermos, one is from harbor freight ($20) and one is a fluke intrinsically safe unit ($1000).

Surprisingly they read about the same on most things. One big difference is the fluke is adjustable for emissivity.

My guess that a specialized thermo for humans is calibrated for emissivity of skin, and may have a narrow and more accurate range. Not sure about that.
Bu I'd bet if my fluke was calibrated and checked with a standard, then it would be accurate enough for the girls I run with.

What I read is that the accuracy is usually higher for the human rated models, and they are usually considered accurate through the range of ~32-45 or 35-45*C.

Skin emissivity may be around .95, but I don't think .95 and a forehead reading are going to give you a reading that correlates to 98.6.

[RWebb]

it would correlate at rest and in the thermal neutral zone, or comfort zone

if hot, the naked apes will dump heat to the face, one of the "thermal windows"

and BTW boys... following up on a comment of sammys... if you heat up a Swedish ski bunny she will glow a lovely pink in some other thermal windows

Enjoy your experiments!

[Tobra]

The one they use at the hospital reads me hot. They hit me with the laser and it reads 101, oral is 98.5. I guess maybe because I am sitting in the sun on the way there.

[sammyg2]

So yer telling us you're a hot head.....

[billybek]

https://www.thermoworks.com/wand

Have thought about getting one of these for my lab/shop.

[dad911]

Originally Posted by billybek

https://www.thermoworks.com/wand

Have thought about getting one of these for my lab/shop.

Looking at specs, it’s range is only 50-108 degrees???

I started this thread because my wife has been using my IR for cooking, I was hoping a forehead one could do double duty in the kitchen. I think not.

[billybek]

Originally Posted by dad911

Looking at specs, it’s range is only 50-108 degrees???

I started this thread because my wife has been using my IR for cooking, I was hoping a forehead one could do double duty in the kitchen. I think not.

I was using my mini IR to check temps on my new to me stick burner the other day.

The forehead IR is calibrated only for that job.

My Raytek Mini Temp is way off when shooting forehead temp. 93 deg F.

[vash]

my dentist took my temp monday with one of those. laser dot to the forehead. it read 98.2. i was impressed. my garage IR indicates i am dead. way cold.

my wife and i each have our own ear read units. i think that is super accurate.

[RWebb]

[David]

I gathered up all the IR thermometers at the shop when this all started months ago. I couldn’t get consistent readings on humans even after playing around with the emissivity setting.

I bought several non-contact human thermometers on Amazon til I got one that was good from at least a foot away. That’s what our security guard uses to check everyone before they can enter the shop.