• Journal of Korean Tunnelling and Underground Space Association
• /
• v.12 no.4
• /
• pp.321-328
• /
• 2010

The study performed an actual fire experiment in order to propose the heat release rate of automobile that is the most basic architectural element for the fire safety design in a tunnel, whose importance has been recognized as the underground traffic tunnels are planned in Korean metropolitan cities. The heat release rate of a van is measured by the large scale calorimeter, in which the law of oxygen consumption is applied, and the fire expansion characteristics in a tunnel by placing two passenger cars nearby one another in the tunnel. As the results, the heat release rate of the van was revealed to be 5.9 MW, and carbon monoxide was emitted 482 ppm at a maximum. In case of two passenger car experiment for the fire expansion characteristics, the adjacent car was ignited about 3 minutes 30 seconds after the fire occurrence, and the complete fire was developed after 15 minutes. The maximum heat release was 9 MW. The results from the actual fire experiment can be an important input data for future quantitative analysis as well as an element applicable to a tunnel disaster preventive equipment design.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.6 no.2
• /
• pp.141-149
• /
• 2004

In this study, smoke movement in tunnel fire with natural and longitudinal ventilation systems has been investigated. Reduced-scale experiments were carried out under the Froude scaling using 14.55kW fire source with a wick and experimental data is obtained with 1/18 model tunnel test. Temperature profiles were measured under the ceiling and vertical direction along the center of the tunnel and poisonous gas was measured at emergency exit point. The results show that refuge time for 225m intervals of emergency exit in case of natural ventilation systems is 256 seconds and critical velocity for sufficient back-layer prevention is 2.8m/s for fire strength of 20MW.

• Tunnel and Underground Space
• /
• v.22 no.5
• /
• pp.365-372
• /
• 2012

This paper aims to evaluate the effects that presence, installation number and capacity of ventilation vent and presence of multiple fire sources have on the behaviour of smoke temperature induced by vehicle fire in road tunnel. Six types of scenarios were assumed and FDS was ran to simulate them. As the number of ventilation vents increases, the smoke temperature are calculated to be reduced, but it is shown that effects exerted by two ventilation vents are almost similar to ones by three ventilation vents. Capacity of ventilation vent has a greater impact on the reduction of smoke temperature than installation number of ventilation vents. Smoke temperatures computed for all scenarios except for scenario No. 1 (without ventilation vent) and scenario No. 6 (with multiple fire sources) above fire source are analyzed to be under $400^{\circ}C$ and it means that the radiation of smoke layer above fire source doesn't induce the ignition of materials around fire source.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 2008.11a
• /
• pp.416-421
• /
• 2008

A growing number of larger and bigger tunnels are being constructed, along with the continuing enhancement of road design speed, thereby increasing the frequency of vehicles using tunnels. For such reasons, a fire in tunnels may lead to such situations. Gases and heat caused by fires are to be blamed for such disasters, as well as the development of vehicles leads to the construction of large tunnels. Therefore this study is to provide for the safety of public and rescue personnel in the event of a fire within the tunnel system. For these purpose, the tunnel system must be protected from collapse during a specified time period. This study introduced the role of ITA, it is to developed guidelines for techniques and materials to answer these structural requirements and make tunnels and their ancillary structures more resistant to fire damage.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.14 no.3
• /
• pp.183-195
• /
• 2012

This study conducted comparative analysis to estimate critical velocity in tunnel fire under variation of grid number and the location and size of the fire source using three-dimensional computational fluid dynamics. In the target tunnel, by one-dimensional way, the calculated critical velocity in the tunnel, 2.22 m/s was estimated, if appling hydraulic diameter, instead of the tunnel height. According to six numerical analysis, each grid number has different position, temperature, and CO concentration of back-layering. In the case of the subject, the case 1 with 0.84 million grid was found to be the most ideal. According to the location and size of the fire source, after three cases for three-dimensional numerical analysis was performed, it is resulted that the location and size of the fire source affect the critical velocity, because air velocity distribution, temperature distribution and CO concentration distribution showed different each case. This is due to the difference of heat exchange area and locations. Therefore, it is necessary to decide appropriate grid number, and the location and size of the fire source for processing techniques through comparison with actual experiment results and three-dimensional analysis.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.6 no.2
• /
• pp.129-139
• /
• 2004

The several assumptions and design parameters to determine the ventilation rate in tunnel ventilation system were examined. In longitudinal ventilating tunnel, the ventilation rate has been determined by the critical velocity above which the smoke propagation to the upstream of ventilating air is prevented. Based upon the examination of assumptions and experimental results, we suggested the improved method to determine the critical velocity. In transverse ventilating tunnel, we found that the ventilation rate has been determined in accordance with the custom rather than fire-smoke dynamics such as the critical velocity in the longitudinal ventilating tunnel. It is because the ventilation rate in the transverse ventilation system has been determined by considering only the ventilation of contaminant by vehicle. To improve the ventilation design parameters based upon the fire-smoke dynamics, we conducted model tunnel fire experiments. From the experimental results, smoke propagating distance and smoke filling were suggested as the design parameter to determine the ventilation rate in transverse ventilating tunnel. And tunnels in Europe designed by the custom is found to have the dangerous nature in view of fire safety.

• Fire Science and Engineering
• /
• v.20 no.4 s.64
• /
• pp.91-97
• /
• 2006

This study was executed to review feasibility on the calculation of critical velocity with a reduced model of an actual tunnel in order to establish the optimum fire protection system for a fire in road tunnels. In a scaled model about 1/29 of an actual tunnel based on the Froude scaling, critical velocity was calculated by visualizing smoke flow and analyzing correlation with temperature. In the experiment, critical velocities at which smoke backflow length became zero showed a small difference within about 5% compared to results calculated by the Kennedy formula, and the relation between smoke flow and temperature distribution appeared similarly without getting greatly influenced by changes in fire intensity.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 2008.11a
• /
• pp.479-483
• /
• 2008

There are no International Standards or Criteria pertaining to fires inside tunnels at the moment, but there are some fire-related regulations in some advanced countries such as Germany and the Netherlands where some fire-related studies have been expedited. Germany has established regulations related to the safety of structures by stipulating Fire Curves of RABT and EBA Tunnels. Also, the Netherlands has established the resistance capacity of structures by stipulating RWS curve so that they can prevent the adjacent area from being damaged due to a tunnel collapse. Hydrocarbon Fire Curve is the standard assessing the behaviour of a structure in a serious fire, by increasing the heating speed and the maximum temperature of ISO 834 Curve, while MHC Fire Curve, which was established in France, realizes more serious fire conditions. In this study, we aimed to develop the basis of full-sized experiments, with which you can assess the fire-resisting capacity against the fire strength of concrete PC panel lining, through the realization of various tunnel fire curves as mentioned above, by developing the heating furnace suitable for the requirements of Fire-Resisting Standards, with which you can assess the fire damage of tunnel concrete lining. We have developed various conditions of the heating furnace and the method to install a thermo couple within the furnace based on EFNARC and KS F2257-1. We have also conducted a calibrating experiment in order to secure its reliability.

• Journal of the Korean Society of Safety
• /
• v.21 no.4 s.76
• /
• pp.7-12
• /
• 2006

Recently, the application of transverse ventilation system with oversized exhaust ports has been increased in bidirectional road tunnel in order to improve smoke exhaust ability. Therefore, in this study, for decision of the optimal smoke exhaust rates in the transverse ventilation system, several standards of nations are compared and numerical simulations with variations of exhaust flow rates are carried out in terms of smoke spread distance by FDS ver. 3.1. As results, in the case of no internal longitudinal air velocity in tunnel, the smoke exhaust rate of $80m^{3}/s$ (the smoke generation rate at HRR of 20MW) is sufficient enough to limit the smoke spread within 250m in 6 minutes after the fire. However, in the case of the internal longitudinal air velocity at 2.5m/s, the smoke exhaust rate should be increased $130m^{3}/s$.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 2007.04a
• /
• pp.134-140
• /
• 2007