ÖNORM EN ISO 12569

This International Standard describes the use of tracer gas dilution for determining the air change in a single zone as induced by weather conditions or mechanical ventilation. The procedures for tracer gas dilution include concentration decay, constant injection and constant concentration. Tracer gas concentration is determined by a gas analyser. Air change rate is directly calculated from the rate of change of tracer gas concentration by the tracer gas decay method. Air flow rate is calculated directly from the tracer gas flow rate by the constant injection or constant concentration method. These test methods are restricted to any single tracer gas. The associated data analysis assumes that the tracer gas concentration can be characterized within the zone with a single value. NOTE The constant concentration test method given in 5.6 is usually used for multiple zones and allows the measurement of the air flow rate from the outside to each zone, if the residential zones are kept at the same concentration.