• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.485-488
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• 2008

Fire intensity in tunnel fire is very severe, which might cause the spalling on the surface of shotcrete and concrete lining exposed to the heat as well as rapidly-reducing stress due to heat transfer by steel material such as anchor embedded in tunnel which plays the critical role in securing the stability of the tunnel. In this study, a fire test to identity the heat intensity(Modifired Hydrocarbon Curve) and the fire resistance of steel materials embedded as parameters, was carried out. And the evaluation to identify the thermal damage, which was based on critical temperature range for thermal damage of steel materials determined according to the road tunnel fire resistance standard established by ITA(International Tunneling Association).

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.1244-1250
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• 2009

In this study it is intended to review the moving characteristics of smoke by performing visualization for the calculation of the optimal smoke exhaust air volume in case a fire occurs in tunnels where transverse ventilation is applied, and to obtain basic data necessary for the design of smoke exhaust systems by deriving optimal smoke exhaust operational conditions under various conditions. As a result of this study, when the critical velocity in the tunnel is 1.75 m/s and 2.5 m/s, the optimal smoke exhaust air volume has to be more than $173\;m^3/s$, $236\;m^3/s$ for the distance of the smoke moving which can limit the distance to 250m. In addition, in case of uniform exhaust the generated smoke is effectively taken away if the two exhaust holes near the fire region are opened at the same time.

• Journal of Korean Tunnelling and Underground Space Association
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• v.6 no.4
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• pp.269-278
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• 2004

Recently, critical velocity has become a topic to attract most interests from the researchers in the field of tunnel safety. As the minimum velocity to prevent smoke backlayering during a fire, many equations have been proposed so far, and the following three equations are being considered as a standard method in Korea to calculate the capacity of smoke extraction fans. Equation by Kennedy based on Froude number, Tetzner' s equation with additional variable, ${\beta}$ to modify the Kennedy's equation, and the equation with the concept of super critical velocity by Wu are studied in this paper for the comparative purpose. A contour map describing the relationship between the critical velocity and the capacity of smoke extraction fans is proposed as a tool to calculate the number of jet fans for smoke control during a fire in the local tunnels.

• Journal of Korean Tunnelling and Underground Space Association
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• v.13 no.6
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• pp.451-462
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• 2011

The smoke control system plays the most important role in securing evacuation environment when a fire occurs in road tunnels. Smoke control methods in road tunnels are classified into two categories which are longitudinal ventilation system and transverse ventilation system. In this study it is intended to review the characteristics of smoke behavior by performing numerical analysis for calculating the optimal smoke exhaust air volume with scaled-model and simulation when a fire occurs in tunnels in which transverse ventilation is applied, and for obtaining the basic data required for the design of smoke exhaust systems by deriving optimal smoke exhaust operational conditions for various conditions. As a result of this study, when the critical velocity in the tunnel is 1.75 m/s and 2.5 m/s, the optimal smoke exhaust air volume has to be more than $173m^3/s$, $236m^3/s$ for the distance of the smoke moving which can limit the distance to 250 m. In addition, in case of uniform exhaust the generated smoke is effectively taken away if the two exhaust holes near the fire region are opened at the same time.

• Tunnel and Underground Space
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• v.8 no.2
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• pp.107-117
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• 1998

In the case of a fire disaster in a uni-directional road tunnel, it is important to determine the critical ventilation velocity to prevent the backflow travelling toward the tunnel exit where vehicles are stopped. The critical ventilation velocity is horizontal velocity to prevent hot smoke from moving toward the tunnel exit. According to Froude modelling, the model tunnel whcih was 300mm in diameter and 21 m in length was made of acryl tubes. Inner section of acryl tubes was clothed with polycarbonate. 1/20 scaled model vehicles were installed to simulate the situation that vehicles are stopped in the tunnel exit. Methanol in a pool type burner was burned in the middle of tunnel to simulate a fire hazard. In this study, the basis of determining the critical ventilation velocity is the ventilation flow rate that is able to maintain the allowable CO concentration in the tunnel section. We assumed that the allowable CO concentration was backflow dispersion index. Futhermore, We intended to find out CO distribution and temperature distribution according as we changed ventilation velocity. The results of this study were that no backflow happened when ventilation velocity was 0.52 m/s in the case of 5.75 kW. If we adapt these results of a fire disaster releasing 10MW heat capacity in real tunnel which is 400m in length, no backflow happens when ventilation velocity is 2.31m/s. After we figured out dimensionless heat release rate and dimensionless ventilation velocity of model test and those of real test to verify experimental correctness, we tried to find out correlation between experimental results of model tunnel and those of real tunnel.

• Journal of Korean Tunnelling and Underground Space Association
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• v.11 no.3
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• pp.223-228
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• 2009

The aim of this research is to analyse the dynamic characteristics of the hot upper smoke layer in case of fire in a tunnel. In order to get the result, computer simulation technique has been used. The fire scenarios were set on the basis of standard cross section of national and express highways through NIST's FDS. As the area of a tunnel increased, the influence of the wind velocity decreased. Furthermore, the influence of the slope of a road was reduced as the wind velocity increased. On the other hand, as the wind velocity increased, the influence of the slope of a road decreased. This phenomena is believed to be caused by the cooling effect of wind which is over 1 m/s in speed, hence, reducing the influence of the effect of slope.

• Journal of Korean Tunnelling and Underground Space Association
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• v.14 no.3
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• pp.183-195
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• 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
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• v.18 no.1
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• pp.41-52
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• 2016

When the queue length of congestion vehicles in tunnel fire is extended beyond tunnel length, the capacity of smoke control system needs to be increased in line with ventilation resistance. However, the vehicle queue length is not defined, so a rational equation is necessary in current fire prevention guideline. This study is intended to propose an equation to calculate the queue length considering the number of vehicles in queue in tunnel fire and evaluate the applicability by tunnel length as well. When it comes to normal tunnel, it is necessary to compare the vehicle queue length with tunnel length up to the length of 1,200 m in a bid to avoid applying the vehicle queue length excessively in case of fire. As a result of evaluation of applicability to model a tunnel, saving the number of jet fan for smoke control appeared to be effective. Besides, quantitative approach to explain the vehicle queue length through the relationship between the percentage of large vehicles and tunnel length was presented. Consequently, when the queue length of the congestion vehicles exceeds the tunnel length in determining the capacity of smoke control system in case of fire, the number of vehicles beyond the tunnel length needs to be excluded from estimating the ventilation resistance by vehicles.

• The Journal of the Korea Contents Association
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• v.19 no.11
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• pp.111-121
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• 2019

Recently, through the services that use drones at fire sites to deliver on-site and road conditions into the situation room and life-saving activities or the deliveries of first aid outfits at the accident scenes that are inaccessible to humans, there are more and more cases of dealing with emergency situations. Therefore, by studying the service design using drones in the initial stage of response to fires in dense residential areas, this study was intended to reify the service design area of the response stage, including the dispatch of fire sites and the fire suppression. To do this, through literature researches, research directions were explored by examining the concept and process review of service design, and by analyzing the application cases using service design. In order examine the validity of this study, a one-on-one interview was conducted to identify the use and problems of drones among incumbent firefighters, and identified the applicability of drones to fire sites by targeting drone experts. Field research was conducted to identify the location and distance of road conditions, site conditions, and 119 safety centers, by making Yongsan-gu, the most vulnerable area to fire in Seoul, as a research sample. And, among the methodologies of service design, Persona and Customer Journey Map were prepared and Insight was derived, by using virtual scenarios for the experience values and behavior analyses of the interested parties. Through these processes, this researcher intended to present the fire-response service design and help establish the direction of service design in the initial stages of fire in Korea.

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