Infrared (IR) thermal imaging is the measurement of surface temperatures. However, to the trained eye it is much more than that. Thermal images, when analyzed by an expert, can provide valuable insight to many problems during a building envelope inspection that would otherwise be difficult to identify or diagnose. Three common types of deficiencies that thermal imaging can be used to assess are water infiltration, air leakage, and insulation.
Water Penetration: Over the course of a day (particularly sunny days) your roof and/or walls will absorb heat. As the temperature cools off, the surface will begin to do so as well. Parts of the substrate that have absorbed water will cool off more slowly. This presents a window of time near dusk when thermal imaging can be used to identify “hot spots” on the building envelope – areas where water has leaked through the building envelope and been absorbed by the substrate, including insulation. These areas stay warm longer than the rest of the system and are thus differently colored in an infrared view than the non-wet areas that have already cooled down. Non-destructive testing using an impedance meter, or destructive testing using a moisture meter or by taking a core of the roof and analyzing it to confirm the presence of moisture can then be performed.
With the advent of drone technology, large areas can be scanned all at once during a building envelope inspection. IEI possesses a drone capable of thermal imaging, and Trey Thomas PE, Project Manager with IEI has a sought-after FAA-issued daylight waiver in his name that allows him to fly the drone during the window of time where hot spots are most visible. Trey has used the thermal imaging capabilities of the drone to great results, saying that it has improved his on-site efficiency many times over. Additionally, the drone footage can conveniently be brought back to the office for further study/analysis.
Air Leakage: Infrared technology can also be used to detect air leakage in your building envelope. Air leakage, as the name implies, refers to interior air that exits a building and/or exterior air that enters the building in an unanticipated way (in other words, not through a properly designed HVAC system). This happens most typically through undetected openings in a building’s façade. Air leakage can be detrimental as it can lead to temperature anomalies and therefore increased heating and/or cooling costs. It can additionally lead to moisture infiltration into the building if exterior air is managing to come in, which can lead to deterioration, and even health hazards such as mold growth.
It may already be obvious how infrared scanning can be useful to assess air leakage. Thermal images can be taken, and similarly to water infiltration on a building envelope, thermal anomalies can be found on the building façade where the hotter or cooler air is entering or exiting the building. With this knowledge, the façade can be properly addressed, and sealed up to prevent further air leakage from causing any problems in your building. Drone technology can also be used for air leakage detection as well, greatly speeding up the process. Trey says that there is drone programming software, such as DroneHarmony, that can map the perimeter of a building. This map can then be used to plot a course around the building that the drone will automatically fly around. This strategy is not only time efficient, but it also ensures that footage is captured for the entire exterior of the building.
Insulation: Lastly, infrared technology can help diagnose problems due to improper insulation. If your insulation in your building is not properly installed, unwanted heat gain or loss can occur. Thermal bridges and missing or defective insulation can lead to energy losses that result in overworked HVAC systems and increased utility costs.
Infrared technology can be used to assess these issues with insulation as the aberrations in temperature due to insulation and thermal bridging will stick out like a sore thumb when viewed through an IR camera’s thermal image (see photos below).
Advancements in thermal imaging are changing the way we can assess problems with a building envelope. Mr. Thomas, who has been doing building inspections for over 15 years, has seen the evolution of thermal imaging technology and how it effects building envelope maintenance. He says that these advancements, coupled with progress and availability of drone technology, make finding building envelope problems much more manageable, and much less intimidating.
Innovative Engineering Inc. has specialized in building envelope inspection for 25 years. IEI’s engineers have extensive experience with various methods of inspection. Additionally, their Certified Remote Pilots comply with FAA Part 107, and also hold a daylight operations waiver which allows them to fly at night, maximizing the effectiveness of thermal imaging. If you feel that it is time to address any problems with your building envelope, give IEI a call today. They will be happy to show you how spending pennies on engineering can save you dollars on construction and maintenance.
Trey Thomas, PE is a Level I Certified Building Investigator by itc Infrared Training Center. Mr. Thomas is also an FAA certified drone pilot and holds a daylight waiver.
Scott L. Weiland PE possesses a sUAS Level I Thermography Certification from itc Infrared Training Center and is BESI Building Envelope Certified.
Drone Harmony is a registered trademark of Drone Harmony AG