Tracer gas techniques are becoming widely used to measure the ventilation rates in buildings.
As more detailed information is required for both energy and indoor air quality purposes,
researchers are turning to complex, multizone tracer strategies. Both single gas
and multiple gas techniques are being utilized, but only multigas are capable of uniquely
determining the entire matrix of air flows. Because of the inherent limitations in the ability
to estimate zonal concentrations, estimates of multizone air flows are highly imprecise
for real buildings. However, exogenous information concerning physical constraints can
allow a greatly improved estimate and interpretation of results if combined with measured
data. This report describes techniques for improving tracer-gas derived ventilation
data using physical knowledge about the system under study.