An Overview of Thermography and its Applications
Over the years, home inspection tools have been developed to make inspectors’ jobs easier. Moisture meters, AFCI/GFCI testers, CO analyzers, PPE, and many more have all helped shorten the amount of time it takes for an inspector to complete a job. Some of these tools made the job safer, some made it faster, and some allowed inspectors to add new services with their reports. Thermography and infrared technology fits all of these categories and has become a leading service that all inspectors should be trained in.
Infrared thermography (IRT) is the science used to capture and process thermal information using non-contact measurement tools. This is done by analyzing infrared (IR) radiation emitted from an object whose temperature is above absolute zero. Because this wavelength exists outside of the visible spectrum of light, infrared measuring devices are required to capture and process this information.
Thermal imaging cameras work by detecting heat signatures and displaying them as a gradient scale, with lighter colors signifying areas that are more hot and darker colors
signifying cooler areas. Unlike visible
light, which is the reflection of wavelengths of light off an object, infrared comes
directly from the image source. This allows IR cameras to function in ways that
traditional visible light cameras cannot.
The general advantages of IRT are the following:
· IRT is a non-contact technology; the devices do not to be in contact with the sources of heat creating a safer work environment.
· IRT creates a two-dimensional thermal image that allows for comparisons with visible light cameras
· IRT works in real-time, allowing high-speed scanning of images
· IRT is safe and effective
· IRT is non-invasive and will not disturb or affect the target area
IRT had widespread use as a military technology in the 1970’s but found itself in commercial use soon after. Today the technology is employed in various fields including medicine, surveillance, engineering, and building diagnostics, which includes home inspections. For home inspectors, knowledge of training of IRT can help diagnose defects that may not have been apparent in a routine inspection, reveal further defects and underlying causes, and can make the job safer.
Infrared imaging or thermography uses specialized instruments that detect and visualize heat spectrums that allow home inspectors to follow the flow of heat through a system. Such instruments include the following:
Spot Radiometer: Also known as a point radiometer, these devices are used to measure single points in the home. The home inspector then compiles the data to determine where there are fluctuations in temperature.
Thermal line scanner: As the name suggests, this device shows a line image of thermal variations superimposed on a scanned area.
Thermal imaging camera: An infrared camera produces a thermal picture of an area that displays heat leakage in greater detail than spot radiometers and thermal line scanners.
Along with these imaging devices, a home inspector may also include a blower door in their thermographic inspections to get more accurate and detailed results. A blower door will create negative pressure in the room, causing air to be pulled in from outside the system that indicate areas of heat leakage.
Applications of IRT in Home Inspections
As a home inspector, it is your job to identify serious defects, but sometimes defects may be completely hidden in plain sight. When included in routine inspections, IR cameras can assist inspectors in identifying these hidden defects. Understanding the principles of IR and how to interpret data will help you create a more complete report.
Here is a list of some applications for IRT:
· Determine if insulation if lacking or deficient
· Determine if there are any air-leaks or abnormalities in heat flowing out of a building
· Determine if there is any moisture intrusion with insulation or other systems (when used with a moisture meter)
· Determine if electrical systems are overloaded or overheating
· Determine if there are leaks or defects with the roof
· Determine defects with the HVAC system
It is important to understand that, like all other types of inspections, infrared technology has its limitations. You should not rely on IRT over other inspection tools and procedures, but rather use all of your tools and knowledge to get the most informed results. When used properly, IRT can help reveal issues that you may never been aware of using non-infrared technologies. Though the science and data may be overwhelming to clients, with training in IRT you will be able to develop your knowledge of the home inspection business and improve your services and reports.
Consumers should always seek inspectors who are Infrared Certified by looking for the Infrared Certified logo below.
This article was sourced from InterNACHI® and the Department of Energy.
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