Air infiltration in Catalan dwellings and sealed rooms: An experimental study

In this study, we performed a series of trials to measure the infiltration air exchange rate (ACH) of several single-family dwellings throughout Catalonia, as well as the ACH of sealed rooms that could be used as indoor shelters. A shelter is an indoor room where people can take protection in case of a toxic gas release, while the toxic cloud passes through the dwelling. Experimental measurements were made using the tracer gas decay technique with CO2 as the tracer gas in 2 periods—summer and winter—with the aim of characterizing air infiltration in Catalan dwellings. The geometric means obtained for the ACH of shelters and dwellings were 0.16 and 0.23 h−1, respectively, that is, lower than those reported for North American (0.56 h−1) and Greek (0.76 h−1) dwellings. In general, the ACH was lower for shelters than for dwellings, and the average reduction obtained in shelters with respect to dwellings was 35%. The largest reductions were obtained in old dwellings with small floor areas and few stories. As for meteorological conditions, we found that the ACH of dwellings was more closely linked to wind speed than indoor–outdoor temperature difference, while the ACH of shelters was more affected by indoor–outdoor temperature and temperature differences inside the dwelling, particularly in dwellings with 3 or more stories.