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Applying IR radiation measurements to the detection of energy losses in structures was one of the first commercial uses for IR sensing and imaging. Generally speaking it is a rather indirect use of the measurement tools available. Point sensors and imagers can provide excellent information concerning the radiation temperature and temperature distribution over building surfaces. The relationship between surface temperature and energy loss, however, depends on a number of physical and environmental factors as well as the insulating characteristics of the structural materials and the integrity of the structural section.
Driven by the energy crisis of the 1970s, which is still very much an issue, communities and government agencies instituted IR aerial scans by adapting military aerial thermal mappers. The purpose of these scans was to provide communities, residents, and commercial taxpayers with information concerning the heat loss characteristics of their buildings. Although only losses through the roofs were detected, unheated buildings did not register at all, and numerous environmental factors clouded the results, these early programs raised community consciousness and identified a new tool for energy conservation. They were also a major driving force in the development of commercially available IR sensing and imaging equipment.
Nationally sponsored and funded building retrofit and weatherization programs were put into effect in European countries (Sweden was the first), in Canada, and in the U.S. Infrared thermal sensing and imaging equipment, now developed specifically for the commercial market, was used extensively in these programs-first to assess the retrofit requirements, and subsequently to check the effectiveness of the work. These were, for the most part, ground-based instruments that provided more comprehensive information about the structures and also provided âground truthâ baselines for the aerial scans. Although priorities have changed, programs of this kind continue. In addition, although the initial thrust of these applications was aimed at energy conservation, it soon became apparent that very many other aspects of buildings and structures could be evaluated using IR sensing and imaging equipment.
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