In many new buildings the indoor air quality is affected by emissions of volatile materials. The emission process may be controlled either by diffusion inside the material or evaporation from the surface but it always involves mass transfer across the boundary layer at the surface-air-interface. Experiments at different velocity levels were performed in a full-scale ventilated chamber to investigate the influence of local airflow on the evaporative emission fr-0m a surface. The experiments included velocity measurements in the flow over the surface and measurements of chamber air concentrations. The results show that the emission, expressed in terms of the mass transfer coefficient, increases with velocity for fixed temperature, relative humidity and air exchange rate. This emphasises the importance of testing materials at the correct velocity and turbulence level in order to obtain the actual emission rate for a given product.
Experiments on evaporative emissions in ventilated rooms.
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Sweden, Stockholm, KTH Building Services Engineering, 1998, proceedings of Roomvent 98: 6th International Conference on Air Distribution in Rooms, held June 14-17 1998 in Stockholm, Sweden, edited by Elisabeth Mundt and Tor-Goran Malmstrom, Volume 1