ISO 12569:2017 establishes methods to obtain the ventilation rate or specific airflow rate in a building space (which is considered to be a single zone) using a tracer gas. The measurement methods apply for spaces where the combined conditions concerning the uniformity of tracer gas concentration, measurement of the exhaust gas concentration, effective mixed zone and/or fluctuation of ventilation are satisfied. ISO 12569:2017 provides three measurement methods using a tracer gas: concentration decay method, continuous dose method, and constant concentration method. NOTE Specific measurement conditions are given in Table 1.