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|NDT.net Issue - 2014-12 - Articles ||NDT.net Issue: 2014-12|
Publication: 11th European Conference on Non-Destructive Testing (ECNDT 2014), Prague 2014, Oct 6-11 (ECNDT 2014)
Session: Infrared Testing, Thermography and Thermal NDT
Evaluating Building Envelope Thermal Resistance by Using Infrared ThermographyIrina Larioshina, Denis A. Nesteruk2, Vladimir P. Vavilov19
Institute of NDT; National Research Tomsk Polytechnic University (TPU)58, Tomsk, Russia
Abstract: A role of infrared (IR) thermography in the energy audit of building envelopes is undisputed. However, this technique is still qualitative being mainly limited with the detection of hidden defects, such as deficiencies of thermal insulation, air in-leaks, excessive moisture, etc. Quantitative estimates are mostly related to the determination of envelope thermal resistance, and here IR imagers often have no advantages to compare to conventional temperature-measuring devices. This comes from the fact that IR imagers can be regarded as multi-point non-contact thermometers but of a rather low accuracy. In fact, some inspection parameters, such as emissivity and background reflected temperature, can be hardly evaluated across large areas to be inspected, therefore, the measurement accuracy is about 0.5-2oC that is too bad when determining heat losses and envelope thermal resistance. Besides, IR cameras cannot measure through-the-wall heat flux density, and the use of standard flux meters makes surveys unacceptably long. In this study, we describe a step-by-step inspection procedure intended for the determination of wall thermal resistance and heat losses by combining point-like measurement of heat flux and fast evaluation of facade temperature by using IR imagers.
Keywords: Infrared Testing (IRT) (964), thermal NDT (105), infrared thermography (72), Inspection (92), thermal insulation (3), reflected temperature,