The reliability of infiltration and air movement data obtained from single tracer gas measurements in large spaces.

The methods available for the measurement of air infiltration and air movement in large industrial halls are restricted by the size of the building and the nature of the operations which take place within it. Single tracer decay measurements are the easiest to perform and this paper examines the possibility of extracting useful information from them. Using a multi-zone representation of the building volume, the properties of tracer decay curves are considered, and the ease of extraction infiltration and air flow data examined by means of simulations. The results show how the error in the derived infiltration rates grow with error in the tracer gas concentration measurements for various methods of treating the results. The simulations are compared to the results of measurements made in a typical industrial hall. Despite the shortcomings of the multi-zone model and the single tracer decay method, it appears possible to obtain reasonable results for the overall air infiltration rates.