Efficient ventilation of VOC spread in a small-scale painting process

A number of surveys have reported that large proportions of workers suffer from eye and respiratory discomfort, headaches and feelings of lethargy on account of volatile organic compounds (VOCs). In a small-scale painting process, therefore, efficient ventilation system must be provided for human health. In this study, ventilation characteristics of toluene have been analyzed in a room of a small-scale painting process with various exit locations and with different suction velocities at the exits. A commercial software FLUENT/UNS has been employed to solve the continuity, momentum equation and mass transfer equation. Steady state flow pattern and toluene concentration have been numerically calculated in cases with different positions and air velocities of the exits, and then transient ventilation characteristics of toluene have been simulated with the calculation of the room mean age and air change efficiency, which are key factors for the evaluation of indoor air quality. The result shows that a careful design of work space is needed to maintain allowable concentration, which may depend on the position of exits and local room mean air age.