Effects of walking and tapping feet on the level of air velocities in the space and particle fluxes close to the floor: Full-scale experimental results

The objectives of this study were to characterize human-activity-induced resuspension from samples of carpet and other flooring materials used in commercial buildings, and determine the effect of different types of ventilation systems (mixing and displacement ventilation) on the concentration of resuspended particles in the personal microenvironment (PME). The experiments were conducted in a full-scale (16 ft by 12 ft by 10 ft high) Indoor Environment Quality (IEQ) chamber at Syracuse University. The air velocities were measured at two levels (H=lm and 1.5m) when the participants performed a series of activities in the IEQ chamber. For tapping feet, the resuspended particle concentrations close to the floor were measured by using Laser Doppler Anemometer (LDA) and Optical Particle Counter (OPC). The particle fluxes were calculated by analyzing the test data from an LDA and an OPC using a newly developed procedure. This paper discusses the feasibility of using the measurements from a LDA and an OPC to estimate the fluxes of particles in different size ranges. The correlation between the increase of air velocity level and the increase of close-to-floor particle flux due to human activities were also discussed. The study shows that the human activities can have significant influence on the level of air velocities and particle fluxes in the PME.