An improved extraction method to determine the initial emittable concentration and the partition coefficient of VOCs in dry building materials

摘要

Based on the extraction method presented by Smith et al. (2008), this paper proposes an improved method, the multi-emission/flush regression method, to simultaneously determine the initial emittable concentration and the partition coefficient. Compared to the extraction method, the proposed method has the following advantages: (1) it is unnecessary for the target volatile organic compounds (VOCs) to emit completely from the material, thus greatly reducing experimental time; (2) it provides a simpler way to obtain the partition coefficients of VOCs for tested materials and can avoid the measurement uncertainties at low VOC concentrations which often occur during the last few cycles of the extraction method; (3) it does not require grinding the building material into powders thus making this method more convenient to use. Comparisons were made between the initial emittable VOC concentrations determined by the original extraction method and the proposed method. Results show good agreements between these two methods. To further validate the proposed method, the type of static chamber developed by Wang et al. (2006) was used to conduct the experiment for a type of medium density board, and formaldehyde was selected as the target compound. Based on the initial emittable concentration and partition coefficient obtained using the proposed method, and the diffusion coefficient obtained by the mercury intruding porosimetry, the chamber formaldehyde concentration was predicted and compared with the experimental measurements. Results show that the predicted chamber VOC concentration using the measured parameters agree well with the experimental data.