This part of IEC 60761 is applicable to equipment intended for simultaneous, delayed or discrete sequential measurement of radioactive noble gas in gaseous effluents discharges into the environment.It is applicable to radioactive noble gas effluent monitors intended to fulfill the following functions: - the measurement of the volumic activity of radioactive gases in the gaseous effluents at the discharge point and its variation with time;- the determination of the gas activity discharged over a given period and/or information on the composition of a mixture of different gases in the discharge.Radon is a natural radioactive noble gas. Its measurement is not