IES Consulting were commissioned to perform an external CFD analysis of buildings at Aston University in order to analyse environmental pollutant dispersion. The focus of the analysis was the spread of contaminants emitted from fume exhaust systems installed on the roof of the university’s SEAS building whilst fume cabinets are in operation.
The project involved an extremely detailed model, with many inputs required to complete the analysis. Steady state CFD simulations were performed for five wind directions with average wind speed, using local weather data. The contaminant concentrations were calculated based on the assumption of a worst case scenario of Band D chemicals being released over a two minute period from a single fume cupboard.
The recommended work place exposure limit for Band D chemicals is 0.5ppm. The concentrations on the building face and ground were observed to be below this limit for all scenarios simulated.
Although the concentration levels were noted to exceed the workplace exposure limit slightly for a few of the scenarios tested, it is important to note that, in all of these cases, the highest concentration levels were local to the roof of the building and in immediate vicinity of the stacks. Since any activity on the roof is expected to be occasional, and a spill even more occasional, it was determined that there would be a low probability of the concentration affecting work force on the roof of the building.