Fire Size In Tunnels

TRB’s National Cooperative Highway Research Program (NCHRP) 415: Design Fires in Road Tunnels information on the state of the practice of design fires in road tunnels, focusing on tunnel fire dynamics and the means of fire management for design guidance.

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"TRB's National Cooperative Highway Research Program (NCHRP) Research Report 836: Guidelines for Emergency Ventilation Smoke Control in Roadway Tunnels presents guidelines for ventilation in roadway tunnels to facilitate human evacuation and emergency responder safety. These guidelines consider tunnel geometrics such as tunnel altitude; physical dimensions (i.e., length, cross section); type of traffic flow (i.e., single or bi-directional flow); and fan utilization and placement. They also consider cargo types and quantities as they pertain to fire heat release rates (FHRRs) and ventilation requirements. The guidelines determine the effects of ventilation on tunnel fires including fire size, and the interaction of firefighting and ventilation system operation. " -- Publisher description

In recent years, a number of high profile accidental fires have occurred in several road and rail tunnels throughout the world. Many of these fires grew rapidly to catastrophic size and claimed many lives. The processes involved in the rapid growth and extremely severe of these fires are not adequately understood as yet. The introduction to this thesis reviews a number of these accidental fires and describes much of the previous experimental research which has brought about the current understanding of tunnel fire behaviour. A detailed review of the relevant parts of elementary fire dynamics is also presented. This thesis addresses two main questions: 1. What is the influence of longitudinal ventilation on fire size in tunnels? and 2. What is the influence of tunnel geometry on fire size? The answers to both these questions are determined using a probabilistic method called Bayes Theorem. This provides a method of answering the above two questions using the handful of experimental data which are available. It is found that the heat release rate (HRR) of a heavy goods vehicle (HGV) fire may be greatly increased in magnitude by longitudinal ventilation, for example by about a factor of 5 with a longitudinal ventilation velocity of 3ms-1. It is also found that longitudinal ventilation may cause a significant increase in the HRR of large pool fires, but may cause a decrease in the HRR of small pool fires and car fires. An equation is derived to predict the influence of tunnel geometry on HRR. It is found that HRR varies principally with the width of the tunnel and the width of the fire object. The HRR of a fire in a tunnel my be increased up to four times due to the geometry of the tunnel.

This book covers a wide range of issues in fire safety engineering in tunnels, describes the phenomena related to tunnel fire dynamics, presents state-of-the-art research, and gives detailed solutions to these major issues. Examples for calculations are provided. The aim is to significantly improve the understanding of fire safety engineering in tunnels. Chapters on fuel and ventilation control, combustion products, gas temperatures, heat fluxes, smoke stratification, visibility, tenability, design fire curves, heat release, fire suppression and detection, CFD modeling, and scaling techniques all equip readers to create their own fire safety plans for tunnels. This book should be purchased by any engineer or public official with responsibility for tunnels. It would also be of interest to many fire protection engineers as an application of evolving technical principles of fire safety.

This report describes measurements of heat release rates in tunnel fires by using the oxygen consumption technique. This technique is commonly used in fire laboratories to measure heat release rates up to 10 MW. Measured heat release rates from fire tests with vehicles (a train, a bus, a subway coach and a simulated truck load) and wood cribs are presented. The total heat release rate was determined by measuring oxygen concentrations and mass flow rates over the tunnel cross section at both sides of the fire. The convective fraction of the heat release rate was determined by measuring the temperature and the mass flow rate. The technique is found to work reasonably well for tunnel fires. However, the measured convective fraction of the heat release rate need to be corrected for heat losses from the hot ceiling jet to the cold walls. The total heat release rate need to be corrected for high yields of carbon dioxide (CO2) in the exhaust gases and for vitiation of the inflowing air in the lower part of the cross section. The study is a joint project between a number of European countries with a project name EUREKA EU 499 Firetun.

The increasing complexity of technological solutions to both fire safety design issues and fire safety regulations demand higher levels of training and continuing education for fire protection engineers. Historical precedents on how to deal with fire hazards in new or unusual buildings are seldom available, and new performance-based building codes

This book features selected papers from the 11th Asia-Oceania Symposium on Fire Science and Technology (AOSFST 2018), held in Taipei, Taiwan. Covering the entire spectrum of fire safety science, it focuses on research on fires, explosions, combustion science, heat transfer, fluid dynamics, risk analysis and structural engineering, as well as other topics. Presenting advanced scientific insights, the book introduces and advances new ideas in all areas of fire safety science. As such it is a valuable resource for academic researchers, fire safety engineers, and regulators of fire, construction and safety authorities. Further it provides new ideas for more efficient fire protection.