Confronto sperimentale tra tecniche di misura della ventilazione naturale degli edifici

The paper is focused on the comparison between two measurement methods typically adopted to characterize the building ventilation: the measurement of the air permeability (pressurization test) and the measurement of the actual air exchange rate (tracer gas decay test). In particular, the criticalities related to the correlation of air permeability and air exchange rate data are highlighted and stressed. To this aim, an experimental analysis has been carried out in a dwelling located in the Central-South Italy performing air permeability and air exchange rate measurements both in the whole dwelling and in parts of it. The results demonstrate that the pressurization test carried out on the whole dwelling does not allow to identify possible air permeability gradients within the envelope. Moreover, the measurement of the actual air exchange rate is strongly influenced by the outdoor microclimatic conditions; thus, the estimate of the air exchange rate on the basis of the air permeability data could lead to significative overestimates with respect to the actual air exchange rates. Therefore, a proper measurement of the local wind velocity and direction is mandatory.