A CO2-controlled ventilation system.

Describes a system installed in the EKONO office building in Helsinki which allows the amount of CO2 in the exhaust air to control the ventilation rate. Uses a CO2 indicator, and adjusts the mixture of exterior and recirculated air so that the amount of CO2 during working hours is kept on ca 700 ppm. Describes use of equipment during winter 1981-82, when exterior air flow is registered. Measures the proportion of CO2 locally in order to study occasional variations that may occur. Studies the proportion of other pollutants in the room air with a gas chromatograph. Uses different types of CO2 indicators to study the efficiency of the control system. Successfulresults indicate that the system can be used in new constructions, as well as in existing buildings.