Abstract

After the energy crisis in 1973, efforts were made to design constructions more airtight to be energy efficient. Since then, sick building syndrome (SBS) has been reported more often as a result of poor indoor air quality (IAQ). Among the proposed strategies to improve IAQ, source control is determined to be the most effective approach. Because of their large surface areas permanently exposed to the indoor environment, building materials are suspected of playing an important role in determining IAQ. Source-specific control, however, requires adequate knowledge about the extent of volatile organic compounds (VOC) emissions of materials so that in decision-making stages, only products with lower emission rates will be chosen and installed. Hence, knowing the characteristics of building materials (diffusion and partition coefficients) is necessary. Moreover, these data are needed as input parameters for VOC emission simulations, which presently suffer from the lack of a database of emission characteristics of materials. Therefore, this study has characterize building materials by measuring their diffusion coefficients ( D ) in different environmental conditions. Based on the twin-chamber method, an experimental set-up was developed to determine the D of five VOCs (octane, isopropanol, cyclo hexane, ethyl acetate, and hexane) for ceiling tile as the building material. By using Fick's law, D was calculated and linked to physicochemical properties of VOCs. The method used also allowed us to investigate the influence of temperature, humidity, and the mixture of VOCs on D. Based on obtained results, a systematic parametric study was conducted to quantify the importance of investigated factors. It was found that among different physicochemical properties, the D is positively related to vapor pressure. Additionally, no significant difference was observed between the D of a single VOC and that of a mixture of VOCs. Also, it was observed that temperature and humidity (in the range of a typical indoor environment) had a minor effect on the measured D