PSI - Issue 11

J.H.A. Rocha et al. / Procedia Structural Integrity 11 (2018) 99–106 Author name / Structural Integrity Procedia 00 (2018) 000 – 000

104

6

PM (Fig. 8). Early and late in the afternoon, periods with a value less than "d", do not show a sharp contrast between purple color (cold) and yellow color (hot). While at noon this difference is more intense.

Fig. 8. Thermograms captured at: (a) 8:00 AM, (b) noon, and (c) 5:00 PM.

Spots "SP1" and "SP2" adopted to portray dry areas and those affected by humidity respectively, are presented in Fig. 9.

Fig. 9. Location of points "SP1" and "SP2" on the subject wall.

Graphic illustrated in Fig. 10 collects ambient temperature and relative humidity of the air, in addition to temperatures referring to spots "SP1" and "SP2" for rainy season. Both at the beginning and at the end of the test there is a sign of a possible typical thermal balance at night. Due to the fact that test took place on a sunny day, at 8:00 AM the environment temperature was lower than area temperature without humidity because the wall had already been heated. At the end of the test, temperatures are greater than in the beginning, because during the day the wall received radiation from the sun. Growth rate of temperatures (environment, "SP1" and "SP2") is not uniform, since temperature changes are slower in the humid mass meaning they take longer to warm up (Barreira 2004; Balaras and Argiriou 2002; Lerma et al. 2011). Another factor that may have influenced "SP2" temperature is wind entering the opening caused by defective window placement, since the presence of air current lowers surface temperature (Melrinho 2014). Fig. 11 shows ΔT values reached during test day. It is possible to notice that the best period for thermographic reading is during morning shift, when the highest ΔT values occur. This is because material is heated, thus confirming the sun is a significant natural source of thermal gradient stimulus for the test. Maximum value (3.9 ° C) took place at 10:00 AM, while the lowest value (1.0 ° C) took place at 5:00 PM. The thermographic image taken at 10:00 AM, time of the highest ΔT value, evidences a sharp contrast between dry and moist areas, where in the latter there is water leakage caused by an opening between the window and the wall (Fig. 12). This graph also shows that in some wall sections moisture was present, but that during all day long, they warmed up due to sunny weather.