An infrared thermography passive approach to assess the effect of leakage points in buildings

It was possible to conclude that the window frame had a larger contribution to the air flow rate than the roller shutter handle (109.4 m3/h and 21.7 m3/h, at a pressure difference of 50 Pa). Qualitative analysis of the thermal images indicated that a colder area near the leakage point can be detected and that it grows with the increase of the pressure difference. The quantitative approach showed that a stabilization of the surface temperature close to the value of the outdoor temperature occurred and the relative differences are around 15% both for the window frame and the roller shutter handle. It also showed that, in most cases, the first pressure step (ΔP = 25 Pa) is responsible for about 60% of the differences in the superficial temperature. A good correlation was found between the proposed Pressurization Thermal Index and the temperature gradient between the exterior air temperature and the initial superficial temperature (ranging from 0.74 to 0.82).