A simple method using tracer gas to identify the main air and contaminant paths within a room.

The main air and contaminant flow paths or the spatial distribution of the age of air (or contaminant) in a room are of great interest to estimate the ventilation efficiency performance. A simple measurement method is presented, which consists to inject or more tracer gases at locations of interest and to analyze the concentration at several other locations, carefully chosen for best accuracy. Response functions can be fitted on these measurements, which are the age of the tracers or of the air or the concentration of the tracers in function of the location. As well the salient paths as the dead zones are determined from these functions. The contribution presents the method and its application and validation on a well known and controlled room.