Modeling particle penetration through cracks in building envelopes
Liu, D. L., and Nazaroff, W. W.
1999
Indoor Air 99, Proceedings of the 8th International Conference on Indoor Air Quality and Climate, BRE, Garston, Watford, UK, Vol. 4, pp. 1055-1059
Liu, D. L., and Nazaroff, W. W., (1999), "Modeling particle penetration through cracks in building envelopes", Indoor Air 99, Proceedings of the 8th International Conference on Indoor Air Quality and Climate, BRE, Garston, Watford, UK, Vol. 4, pp. 1055-1059.
| Abstract: |
| Particle inhalation is an important pathway for human exposure to toxic substances. People spend most of their time indoors, so a sound understanding of particle penetration through building envelopes would improve our knowledge of the contribution of ambient particles to total human exposure. In this paper, particle penetration through rectangular, smooth-walled cracks is modeled. Steady-state airflow is determined from crack geometry and the pressure difference across the building envelope. Three particle deposition mechanisms are considered: gravitational settling, Brownian diffusion, and impaction. Predictions are made for particle diameters over the range 0.001-100 ¦Ìm, pressure differences of 4-10 Pa, crack heights of 0.05-1.0 mm, and a crack length of 3 cm. Particle size and crack height strongly affect particle penetration. Particles with diameter in the range 0.1-1.0 ¦Ìm are predicted to have the highest penetration factors, greater than 0.85 for a crack height of 0.25 mm or larger. Gravitational settling controls the deposition of large particles and Brownian diffusion controls deposition of small particles. |
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