Flammable Liquid Fire Consequence Modeling

The recent expansion in the production of shale petroleum crude oil, combined with the lack of new pipeline construction, has placed the railroads at the center stage for safe and efficient transport of very large volumes of this commodity. Petroleum crude oil poses fire risk in the event of train accidents. The consequence modeling based on the US DOT Emergency Response Guidebook (ERG) or ALOHA (Areal Locations of Hazardous Atmospheres), a popular atmospheric dispersion model used for evaluating releases of hazardous chemical vapors, may be overly simplistic and limited to estimate the risk of flammable liquid releases. This paper aims to address this gap and develop a simple model to estimate flammable liquid release consequences, focusing on petroleum crude oil. A flow model using the spatial geographic information system (GIS) and the digital elevation model (DEM) is developed. The methodology was illustrated with a case study comparing the results from the model to the area affected from the LacMégantic accident. Although the model does not consider advanced flow types or fire propagation, the results accurately describe the consequences of the accident, demonstrating the potential capability of this methodology to estimate the consequences of a crude oil release. INTRODUCTION Arguably the worst railroad accident in more than a century in North America took place on July 6th, 2013 in LacMégantic, Quebec, Canada. The derailment of 63 out of 72 tank cars transporting petroleum crude oil, and consequent releases of several of these cars, devastated the downtown area destroying more than 30 buildings, caused 47 fatalities (5 are still officially missing), and triggered the evacuation of about 2,000 people [1]. Despite this tragic accident, North American railroads are considered one of the safest modes of transportation for hazardous materials, “with 99.9977 percent of all shipments reaching their destination without a release caused by an accident” [2]. Given their reliability, railroads will continue transporting large volumes of crude oil and other hazardous materials. However, events like the Lac-Mégantic accident highlight the need to further improvement in railroad hazmat transportation safety, and particularly of the consequence assessment for crude oil transported by rail. The lack of a specific consequence model for flammable liquid hazmat releases is addressed in this paper. A flow model using the spatial geographic information system (GIS) and the digital elevation model (DEM) is developed. The model can be used to predict the area of potential fire exposure and prioritize emergency responses. A case study simulating the accident in Lac-Mégantic is also Proceedings of the 2014 Joint Rail Conference JRC2014 April 2-4, 2014, Colorado Springs, CO, USA