Computer Modeling in Commissioning Emergency Ventilation Systems

This paper gives an overview of the state-of-the-art computer modeling techniques in the design and commissioning of emergency ventilation systems in transit stations. A number of examples are presented. The first example is on tunnel smoke control and discusses the implications of using computational fluid dynamics modeling to account for the uncertainty in tunnel airflow measurements. The results suggest a 5-10% over-estimate as the systematic error due to the measurement grid. In the second example, subway environment simulation is used to assess the performance of parallel-fan fan plant without fan isolation dampers. A 20% flow leakage or decrease in ventilation performance was predicted. Both the advantages and limitations of applying computer modeling to evaluate the performance of emergency ventilation are discussed in the paper.