Domestic kitchen exhaust systems: Performance assessment

Abstract

A microprocessor-controlled tracer gas system was used to measure ventilation and interzone air movement in a house equipped with a wall-mounted hood and a kitchen extract fan. The air velocity profile under the wall-mounted hood was also measured using a hot-wire anemometer. The results indicated that extract rates of typical kitchen exhaust systems are significantly lower than that recommended by the British Standards Code of Practice BS5250. The airflow velocity measurements showed that the wall-mounted hood unit has a low capture efficiency at the cooking surface and that the performance of the hood in this region is mainly dependent on the effect of thermal buoyancy. The exhaust systems tested were unable to prevent airflow at high rates from the kitchen to the living space through an open doorway, even at small interzone temperature differences. Significant movement of moisture and other cooking contaminants from the kitchen to the adjacent rooms would occur under these conditions.