A quantitative estimate of the accuracy of tracer gas methods for the determination of the ventilation flow rate in buildings.

This paper presents a quantitative estimate of the error of the decay and constant concentration method. A number of tests were carried out in an indoor test house located in the laboratory hall at the National Swedish Institute for Building Research. The relevant meaning of the concept of air-exchange rate is discussed and an appropriate terminology is suggested. The theoretical background, based on a multi-cell model, of the two tracer gas methods is given. Results of the studies of the accuracy of the tracer gas methods are presented, with some results of the studies of the effect on the infiltration rate due to different operation modes of mechanical ventilation systems.