A Simple Method Using Tracer Gas to Identify the Main Airflow and Contaminant Paths within a Room

The main airflow and contaminant paths or the spatial distribution of the age of air (or contaminant) in a room are of great interest in estimating venrilation efficiency. A simple meusurement method is presented which consists of injecting one or more tracer gases at locations of interest and analysing the concentration at several other locations, carefully chosen for best accuracy.Response functions can be fitted to these measurements, which are the age of the tracers or of the air or the concentration of the tracers as a function of the location. The salient paths, such as the dead zones, are also determined from these functions.The paper presents the method, its application and validation in a well controlled test room.