Use of infrared thermography for detection of moisture sources in internal walls of buildings

Abstract The use of infrared thermography has become the theme of studies in several areas of the construction industry. However, research studies on detecting the presence of moisture in buildings are still under development. The main objective of this article was to study the feasibility of the use of thermography in the detection of infiltrations due to accidental causes in internal walls. The methodology consisted of the construction of masonry walls made of ceramic bricks with different coating configurations: uncoated, with plaster, plaster with latex paint, plaster with acrylic base paint and plaster with ceramic set with plaster glue. In each prototype, a drilled pipe was inserted to simulate water leaks. The infiltration progress was verified by means of thermograms, for a period of 2 hours with constant flow, and at 48 hours and one week after the beginning of the simulation. The results confirm that thermography may be effective in detecting the region containing the focus of hidden infiltration, provided the coating is not impermeable. This fact can be observed in the thermal gradients produced in the porous coatings, where ΔT ranged from 2.6 to 3.8 º C, whereas coatings with waterproof characteristics had a maximum ΔT of 2.2 ºC. In addition, the type of coating directly influences the time required for the appearance of the moisture spot to become apparent.

摘要：红外热成像（infrared thermography）技术的应用已成为建筑业多个分支领域的核心研究方向。然而，针对建筑内部潮气检测的相关研究仍处于发展阶段。本文的核心研究目标为探究热成像技术用于检测内墙意外渗水的可行性。本次研究的试验方法为砌筑采用不同涂层配置的陶瓷砖砌体内墙：分别为无涂层墙体、纯抹灰墙体、抹灰层涂刷乳胶漆墙体、抹灰层涂刷丙烯酸底漆墙体，以及抹灰层搭配石膏胶黏结陶瓷涂层的墙体。在每个试验原型墙体中，均预埋钻孔管道以模拟漏水场景。研究通过热像图（thermograms）分别在恒流供水2小时、模拟开始后48小时以及1周时，对渗水进程进行监测验证。试验结果证实，当涂层不具备防渗性能时，热成像技术可有效定位隐蔽渗水的焦点区域。这一结论可在多孔涂层产生的温度梯度中得到验证：多孔涂层的温差ΔT范围为2.6~3.8℃，而具备防水特性的涂层最大温差仅为2.2℃。此外，涂层类型会直接影响潮气斑点显现所需的时长。