Project Description

Urban subway systems remain among the most susceptible to a terrorist attack by biological or chemical agents (BCA) because they are heavily trafficked and have limited points of egress. The combination between efficient creation of casualties and anonymity afforded to terrorists make subways attractive targets. However, the disproportionate amount of passengers to subway employees, limits the ability of transit workers to identify suspicious activity. Terrorist attacks in Tokyo (1995), Paris (1995), Madrid (2004), and London (2005) contribute to concerns over train and subway vulnerability.

The long-term goal of this research is to improve the ability of transit authorities to respond to a release of a BCA in or outside of a subway station, by informing policy regarding:

• Placement of BCA sensors within subway stations,
• Necessary sensitivity and response time of sensors to monitor BCAs,
• Ventilation design considerations to mitigate potential exposure to BCAs, and
• Development of risk-minimizing egress strategies.

The short-term goals of this research is to acquire detailed flow field information in a series of fluid dynamics experiments intended to characterize the transport and dispersion of a surrogate BCA into, across, and out of a scale model of a New York City (NYC) subway station. The scale model will be modular, allowing for degrees of complexity in subway station design and therefore flow pattern to be characterized. The experiments will use existing in-house resources, including a wind tunnel and a particle image velocimeter (PIV). The flow field information will be used to develop and validate a Multi-Compartment Mass Balance (MCMB) model, and to evaluate the Subway Environment Simulation (SES) model. The former model will be designed to account for both transport and dispersion of the BCA in and across the station, while the latter model only accounts for transport of BCA within subway stations.

The immediate goals of the proposed work are to:

1. Identify current practices employed by the NYC MTA for ventilation in normal and ‘emergency’ conditions.
2. Develop detailed Autocad drawings of the 137th St. and 145th St. 1 line stations.
3. Identify construction materials for the scale model that will represent the texture of materials used in the actual stations.

The results of the proposed work will allow the short-term goals of the overall project to be realized. The ventilation practices will inform the placement of fans, ducts, and gratings in the station. The scale model will be constructed per the Autocad drawings.

This project was co-sponsored by the Research and Innovative Technology Administration of the U.S. Department of Transportation through the University Transportation Centers program.

This project was funded through UTRC's Emerging Scholars Initiative.