November2017

INFRARED BUILDING

INSPECTIONS Old Science – New Tool

By Ian Martin, Level 1 Thermographer, FWH Associates, P.A.

© iStockphoto.com

T hermal radiation is emitted from every single object around you right now, you just can’t see it. No, not the radiation that causes cancer or three-eyed fish but the thermal signature an object gives off. Every object in the universe has the ability to retain and emit heat. A thermal imaging camera allows visualization and capture of this heat signature data through photography and videogra- phy. The images created by these special cameras are as beautiful and intriguing as they are informative. However, against popular belief and the movie Predator, infrared cameras (or vision) do not grant the ability to see through walls … or clothes for that matter! What is Thermography? Thermography is the ability to study heat or infrared radiation emitted from objects and structures. The science of observing thermal signatures has been around since the age of the pyramids. Doctors of the time realized that some illnesses and diseases directly correlate to the surface temperature of the human body. To determine if there was

a temperature difference, they would apply mud to the con- cerning area and establish the difference in drying rates. In the early 1900’s, scientists used photography to capture the infrared spectrum which was considered the start of modern thermography as we know it. Throughout the next few decades, the quality of imaging improved drastically, particularly as a result of military research during World War II and the Korean Conflict. The science was crucial in various areas of the battlefield, including the observation of enemy troops in low light conditions (1). The use of this technology became declassified soon after these events and several industries immediately took advantage of its capabilities, such as the medical and utility industries. In order to really understand what a thermal image is portraying, a basic understanding of Thermal Dynamics is required. While a PhD in Physics may be overkill for observ- ing a building façade, the principles must be understood to interpret the images properly. Here is a good place to start your basic understanding of thermal dynamics: object s inherently absorb, retain and emit heat. This universal prop-

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