A methodology to investigate the particulate penetration coefficient through building shell

Dust penetration coefficient was defined to quantify the ability of buildin g fabrics, door gap and window louver in reducing the amount of outdoor par ticulate matter brought into the building by infiltration. An office premis es were selected as the controlled environment in this study. In order to m inimize the impact of other factors, continuous measurements were conducted at night when the air conditioning units were turned off and when no indoo r generation term was available. Exponential decay curves of the indoor par ticulate levels were obtained from which the penetrating coefficients were determined. Indoor dust removal mechanisms were discussed in the paper and within the experimental conditions, the dust penetration coefficients varie d from 0.69 to 0.86. A cascade impactor was also used in the experiment to collect particle size distribution in the range of 0.43-10 mu m. The size d istribution was extended to the range of 0.05 mu m by extrapolation techniq ue. The modal size of the particulate matter (by mass cone.) was found at a bout 1 mu m reflecting the inability of HVAC filter in removing dust around this size range. The dust penetration coefficient and size spectrum are us eful for building researchers in quantifying influence of HVAC unit and bui lding fabrics on indoor particulate characteristics. (C) 1999 Elsevier Scie nce Ltd. All rights reserved.