Analysis of building facade defects using infrared thermography: Laboratory studies

Facades inspection with infrared thermography: cracks evaluation

“…4b), all three spots are very clear, with values of 9.4, 8.7, and 6.6°C, for A1, A2, and A3, respectively. Regarding thermographic analysis, these values are representative of anomalies [6,4]. Delta-T is maximum at 9:00 a.m. and 10:00 a.m., dropping heavily until 2:00 p.m., and stabilizing close to 1.0°C.…”

“…The defects or anomalies cause disturbances to the heat flux, leading to a distribution of different temperatures on the surface of the facade or element, which is captured by the thermogram. The main difficulty, in thermographic inspection, is to identify at which heat flux condition the defects are visualized, and how they manifest themselves [3,4]. Different types of inspection may be used when applying the thermography.…”

“…Comparatively, for the same exposure conditions, a greater Delta-T may indicate a more severe condition for the anomalies [12]. Bauer et al [4] correlated the depth of cracks with the Delta-T values measured in laboratory heating cycles and reported that higher Delta-T values are associated with deeper cracks. Thus, the thermogram obtained from the quantitative thermography study can indicate the severity degree of the anomaly.…”

“…The studies have shown a strong dependence on the variations of surface temperature and sun incidence, with no agreement about the criteria regarding the best time to make the thermographic inspection (day or night) [15,16]. It can be said, obviously, that the weather conditions in the country where the studies are being performed are an important variable in the processes and results since they involve differentiations of heat flux for each study [4,14].…”

“…Most often, thermography has been used to observe the location of cracks [4], and not as quantitative thermography, i.e., without evaluating the severity of the anomaly.…”