When investigating an issue, it's important to look for key indicators that are difficult for the naked eye to see. This is true in many contexts, including police work and firefighting. Another scenario where it's important to uncover details that are difficult to see is home inspections.

In all of these cases, professionals can use thermal imaging. The human eye cannot see changes in temperature on its own, but with the right technology, experts can spot problematic areas based on temperature distribution.

So what exactly is a thermal imaging camera, and how can technicians use them to their advantage?

How thermal imaging cameras work

Thermal imaging cameras can see something the human eye cannot — infrared radiation.

What is infrared radiation?

In the 1800s, Austrian physicists Josef Stefan and Lugwig Boltzmann discovered that there is a correlation between the absolute temperature of an object and the amount of radiation it emits. The Stefan-Boltzmann law states that the thermal radiation from an object is proportional to that object's absolute temperature to the fourth power.

Put simply, these two scientists discovered that heat impacts infrared radiation, and data on one of those qualities can be used to discern data on the other.

However, while infrared radiation can be felt in the form of heat, it cannot be calculated using human senses alone. That's where thermal imaging cameras come into play — they are capable of detecting radiation, which is then depicted as visible light on a display screen so users can make sense of it.

But what determines the amount of radiation a certain object can emit? To answer that, we have to look at emissivity.

What is emissivity?

The emissivity of an object refers to its ability to emit infrared radiation. Different materials have unique capabilities. There is a theoretical concept called a "blackbody," which has an emissivity of 100% and does not exist in real life. It's used as a reference point from which to compare the emissivity of real bodies, which is influenced by the object's material and properties of the surface as well as its temperature and specifications of the thermal imager being used.

Real bodies always have emissivity of less than 100% because they reflect radiation. Whereas a theoretical blackbody absorbs all radiation, real bodies absorb some and then reflect the rest. It's a similar concept to how an object that is black in colour absorbs all visible light, whereas something that is red reflects red light, or something that is green reflects green light.

The emissivity of an object is helpful to know because it puts the amount of infrared radiation it is emitting into context. Objects that are smooth or shiny reflect more radiation than ones that are rough, even if they are made out of the same material.

What is a thermal imaging camera made of?

Despite its name, a thermal camera is quite different from a camera used for photography. Cameras photograph what the human eye is already capable of seeing — although those with a high resolution might be able to uncover minute details that are difficult to discern.

A thermal imaging camera, on the other hand, has components that give it temperature measurement capabilities. While it has a display and optic system, like a regular camera, it also has a detector with thermal sensitivity. Additionally, thermal imaging cameras contain amplifiers to make the temperature distribution more defined, and a signal processor to detect temperature changes.

A photographic camera typically has a glass lens, but glass is incapable of transmitting infrared wavelengths. That is why thermal imaging camera lenses are usually made out of germanium or zinc selenide.

Detecting infrared radiation levels in homes and buildings is a great way to find problems and analyse energy consumption.

Infrared radiation data can discover problems in a building or home.Infrared radiation data can discover problems in a building or home.

What temperature distribution data is used for

So now we know how thermal imaging cameras work. Why are they useful for technicians?

What does a temperature hot or cold spot reveal?

Thermography can help fight far more than crime and fires — it can also detect major issues in a building.

Temperature data will show unusually cold or warm areas, which almost always indicates some sort of a problem that needs to be investigated.

Important uses for infrared thermography are:

  • Monitoring air quality.
  • Detecting gas leaks.
  • Locating mould.
  • Discovering termites or rodent infestations.
  • Assessing foundational problems like cracks
  • Discovering ventilation and insulation inconsistencies.
  • Finding electrical problems.
  • Analysing power usage.
  • Checking for defects in solar panels.

These are just some of the issues that thermal detectors can spot. Well-executed thermography can be the difference between a safe building and a dangerous one.

Quantitative vs qualitative thermography

There are times when qualitative temperature data is sufficient, and times when quantitative data is needed for an investigation.

Qualitative thermography shows a thermograph, which is a thermal image depicting the temperature distribution in high resolution. Quantitative thermography, on the other hand, contains more details. It detects the exact temperature of every pixel in the thermal image, giving a much more number-focused and data-driven result.

Finding the best thermal imaging camera

Deciding what type of thermal imaging camera you need will depend on your intended use. Do you need quantitative data, or will qualitative data suffice? And how many additional features do you want the camera to have?

Either way, Testo's thermal imaging cameras are the best on the market.

Testo's products

The testo 883 is designed for both maintenance purposes and building energy consulting. Our high-end thermal imaging camera has a resolution of 320 x 240 pixels, producing a detailed thermal image. The cameras are highly sensitive and intuitive, so they ensure no important temperature data goes unnoticed.

Download the testo 883 brochure to learn more.

Testo's thermal imaging courses

Not only do we offer high-quality cameras, but we also take it upon ourselves to teach you how to use them.

We offer thermal imaging courses for technicians, including an Introduction to Thermal Imaging, Practical Hands-On Training for your testo Camera, and Certificate I and II in Thermal Imaging, offered by our training partner and TIC Distributor IPI.

Contact us today to learn more about our thermal imaging cameras and services.

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