How to Use an IR Gun

Measuring the temperature of something from a distance? Why yes, there is a tool for that. It's called an infrared gun — or an IR gun for short. An IR gun has a lot of potential applications. With an essential role in industries like firefighting, electrical engineering, and healthcare, IR guns have become an important tool in our society.


What is an IR gun, and how does it work?


Infrared thermometers read infrared radiation to provide the temperature of an object’s surface. Any object with a temperature higher than absolute zero has infrared radiation, a type of energy emitted by moving molecules. The higher the temperature of an object, the faster the atoms and molecules are moving. Thus, the temperature of an object is directly related to the amount of infrared radiation it's emitting.


We can't see infrared radiation, but we can feel it. It is the heat that we feel from the sun, or the warmth that we feel from a fire. This is the heat that IR guns read when they are measuring an object's temperature.


Just as you can focus or reflect light, you can focus and reflect infrared radiation. This is key to how the IR Gun Works. It focuses the infrared radiation onto a thermopile, which turns thermal energy into electric energy. The thermopile absorbs the radiation and converts it into heat, which provides the temperature measurement.


Applications of an IR gun


There are a lot of cases when a normal thermometer just won't cut it. Infrared thermometers offer measuring capabilities from a distance. In many situations, that distance is essential either for safety or convenience purposes.


Take, for instance, a building fire. To conduct emergency rescue services safely, firefighters may need to check for hotspots when they enter a building. The temperatures of a fire are obviously too high for direct contact. By using an IR gun, firefighters can check temperatures from a distance. These accurate reads help them to proceed safely.


Firefighting isn't the only dangerous context where IR guns play a potentially life-saving role. They can also be used to take the temperature of an area that may be hazardous or include toxic materials. Or, when workers need an accurate read on industrial equipment like furnaces, IR thermometers can provide it without making dangerous contact.


Sometimes it's not the high temperatures that make the IR gun convenient, but the high distance. Think about how much more convenient it is to be able to point an IR gun at an air conditioning unit several stories up, rather than going to the trouble to reach it.


IR thermometer guns are also great for reading the temperature of a moving object. They are responsive enough to register temperature right away. Because of this, they can quickly grab the temperature of active machinery, or objects moving quickly on a conveyor belt.


How to use an IR gun


Even though the mechanisms of an IR gun sound complicated, you might still think the tool itself is straightforward to use. But before you dive in there are some guidelines to consider. It's true that you simply point the thermometer at the object you want to measure, but there's more to it than that.


One of the most important things to keep in mind is that an IR gun does not just measure a dot. Most IR guns come equipped with a laser pointer to help guide your measurement. But the laser shows the general area of measurement, not the exact spot. The thermometer reads an area that is larger than the laser pointer alone. And the farther away you are, the larger the area that it's measuring.


This is the “distance-to-spot” ratio, and it varies from one IR gun to another. Each infrared thermometer will tell you what its distance to spot ratio is, so that you can calculate how close you need to be to get an accurate result. Generally, the more expensive a thermometer, the larger its distance to spot ratio will be. So, the more you're willing to spend, the more accurate of a read you can get from farther away.


How you intend to use your IRA gun will help you decide which model you should buy. Being able to understand the distance to spot ratio is a big part of using an IR gun accurately.


Things to watch for


At Alliance Calibration, we prioritize accuracy in everything we do. That's why we're going to give you even more tips for how to get the most accurate readings with an IR gun.


Another term you should familiarize yourself with when using an IR gun is “emissivity.” Emissivity measures how effective an object is at releasing thermal radiation. We use a number between 0 and 1 to describe an object's emissivity. The number 0 Indicates an item that is non-emissive, and the number 1 means that an item is as emissive as it gets.

 Emissivity is defined as the ratio of the energy radiated from a materials surface to that radiated from a perfect emitter, known as a blackbody, at the same temperature and wavelength and under the same viewing con

Since an IR gun works by reading an object's thermal radiation, emissivity influences the reading's accuracy. As such, it's important to know what types of objects have low emissivity, because those will give off inaccurate reads.


Shiny surfaces like reflective metal are less emissive. They are not creating the same amount of infrared radiation that a dull item would create at the same temperature. Some IR guns can adjust to work with various levels of emissivity. If you expect to measure the temperature of low-emissivity objects, look for one of these. They will allow you to set the emissivity levels too low, medium, or high.


When you're taking a temperature with an IR gun, you should also be aware of the area’s conditions. Things like dust or smoke can obscure an accurate read by deflecting infrared radiation. Similarly, if the lens is dirty on an IR gun, it might prevent the tool from getting an accurate read.


Speed, accuracy, and convenience are built into the IR gun’s functionality — if you use it correctly. Make sure that you follow the guidelines and use an IR gun with the distance-to-spot ratio you need.

Phil Wiseman

Phil Wiseman

Phil Wiseman is Chief Marketing Officer at Alliance Calibration. He earned a B.S. in Chemical Physics from Centre College. Phil is an ASQ Certified Quality Auditor and ASQ Certified Manager of Quality/Organizational Excellence.

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