Expresses air infiltration rate measured using tracer gas in 2 similar town houses in terms of wind speed, wind direction, indoor-outdoor temperature difference, average rate of boiler firing and fraction of time that doors are open. Method yielded reproducible rates of air infiltration within 0.1 air exchanges per hour in any single one-week run once outside temperature, wind speed and wind direction were allowed for. States results partly reveal set of physical principles determining house air exchange rates which are so far poorly understood.
Estimates of air infiltration in houses based on tracer gas measurements have usually assumed house is a single perfect mixing chamber with incoming air instantaneously and uniformly diffused to all parts of the interior. Points out that in reality some parts of the house - basement or rooms with doors closed - exchange air only very slowly with other parts so that actual mixing is far from instantaneous. Presents theory and mathematics necessary to apply tracer gas method to buildings of many chambers.
Discusses use of tracer gases for the measurement of natural ventilation rates States advantages of using radio isotopes are increased speed and sensitivity. Gives expressions for calculating air change rates using radio isotopes from thedecrease in signal. Suggests use of krypton 85 or Xenon 133 as tracers. Discusses errors in the method. Reports study of air quality in a naturally ventilated building in Yakutsk. Air change rates, temperatures and concentrations of carbon monoxide were measured in kitchens with gas stoves.
Describes experiments emitting a gaseous tracer (methane) into a ventilated test room and measuring gas concentration with rapid-response hydrocarbon analyser. Parameters were contaminant source location, sample location and ventilation rate. Measures equilibrium concentrations and rates of decrease in concentration following cessation of tracer release. Subjects data to multifactorial analyses.
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