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www.sname.org/sname/mt July 2012 vent from the vehicle into an in nite vol- ume. Figure 3 provides a comparison of the total heat release rate of the passenger vehi- cle given the two types of lining materials being considered. GRP A results in a peak heat release rate of approximately 9.2 MW and exhib- its a de ned decay phase shortly after the peak heat release rate is experienced. GRP B results in a maximum heat release rate of approximately 12.0 MW with a sustained heat release rate of approximately 11.0 MW subsequent to the peak for the remaining simulated duration. Because the maxi- mum heat release rate was the focus of this analysis, the simulations were not run until complete burnout. e example analysis provided here illustrates that the installa- tion of GRP A will result in a maximum heat release rate of less than the stated criterion of 11.0 MW. e other material considered, GRP B, results in a maximum heat release rate of approximately 12.0 MW, which exceeds the stated limit. Limitations is approach uses a combination of small- scale test data and simpli ed analysis tools (b-parameter calculation and simple ame spread model). Each component has associ- ated uncertainty. At the small-scale test level, di erences in materials (from one sample to another), variations in data collection from di erent test apparatus, and potential errors in reporting may exist. Development of common protocols for testing, apparatus calibration, and data reporting would help reduce uncertainty in the data. Because the simpli ed analysis techniques (b-parame- ter and ame spread model) are intended to provide a simple screening approach, some of the complexity associated with fac- tors such as vehicle geometries was ignored (for example, it was assumed that walls and ceilings were flat with no obstructions). Geometric details were later incorporated with the integration to CFD. MTNicholas A. Dembsey is a professor of re protection engineering at Worcester Polytechnic Institute (WPI). Brian J. Meacham is an associate professor in the De- partment of Fire Protection Engineering at WPI. Kurt Schebel is a re engineer with Arup?s New York o ce. Matthew Johann is a senior re protection engineer with Arup?s Boston o ce. Je rey Tubbs is a principal with Arup. Jarrod Alston is an associate re engineer with Arup?s Boston o ce. This material is based upon work supported by the Science & Technology Directorate, U.S. Department of Homeland Security, under Award Number 2009-ST- 108-000013. The views and conclusions contained in this docu- ment are those of the authors and should not be interpreted as necessarily representing the o cial policies, either expressed or implied, of the U.S. De- partment of Homeland Security. FIRE SPREAD Because the maximum heat release rate was the focus of this analysis, the simulations were not run until complete burnout. Further Reading To learn more about modeling re spread, check out the following resources. Meacham, B.J., Dembsey, N.A., Schebel, K., Johann, M., and Tubbs, J., Rail Vehicle Fire Hazard Guidance, Final Report , developed under DHS Grant 2009-ST-108-000013, U.S. Department of Homeland Security, Science and Technology Directorate, International Cooperative Programs O ce (2010). Meacham, B.J., Dembsey, N.A., Johann, M.A., Tubbs, J.S., and Schebel, K., ?A Simpli ed Approach for Assessing Initial Fire Development and Spread in Passenger Rail Vehicles,? Transportation Research Record: Journal of the Transportation Research Board, 226 1 (2011). Meacham, B.J., Dembsey, N.A., Johann, M., Schebel, K. and Tubbs, J., ?Use of Small-Scale Test Data to Enhance Fire-Related Threat, Vulnerability, Consequence and Risk Assessment for Passenger Rail Vehicles,? Journal of Homeland Security and Emergency Management , 9:1 (2012).