AIVC - Air Infiltration and Ventilation Centre

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air change rate

Predicted and measured air change rates in houses with predictions of occupant IAQ comfort.

The purpose of this study was to test an Indoor Air Quality model on a variety of Canadian homes, and use this model to determine the optimal ventilation levels necessary to provide appropriate comfort levels. The Indoor Air Quality model tested (the AQ1 program), was a single zone hour-by-hour model of air leakage, mechanical ventilation and pollutant concentration. Measured weekly air change rates were compared to the model's predicted rates, and sensitivity analysis' performed on a number of inputs.

Single-sided ventilation: a comparison of the measured air change rates with tracer gas and with the heat balance approach.

In the frame of the European PASCOOL project, several experiments regarding single sided ventilation were carried out at BBRI in the outdoor PASSYS test cel. The test room of 30 m³ has a vertical window of about 1 m². During a first measurement period, an open cold box, which allows one to control the vertical wind speed, was placed in front of this window. During a second measurement period, the window was directly exposed to "real wind". The air change rates were evaluated by using two different methods: a tracer gas technique and the heat balance approach.

Air change effectiveness measurements in two modern office buildings

Local age of air and air change effectiveness were determined in two office buildings using tracer gas techniques to study the air applicability of the associated measurement procedures in mechanically ventilated office buildings. Measurement issues examined include the establishment of a uniform tracer gas concentration at the start of the test and the relationship of ventilation system configuration and system operation to the test procedure.