This paper presents a process permitting to design exhaust-air cleaning systems for rubber outlets. The procedure is based on determining the concentration of gaseous organic compounds (total carbon = TC) in relation to the exhaust-air flow which is directed in this case, through a cooling section where it is cooled down in predetermined stages so as to reach the saturation concentration values. Dew point curves can be derived from the pairs of values of concentration/exhaust-gas temperature. When the dew point curves are known, the maximum exhaust-gas temperature necessary can then be specified, depending on the limit concentration required.