• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.10
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• pp.665-671
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• 2010

In the present study a 1D-3D numerical simulation was performed to analyze the fire safety in a rescue station of a long railroad tunnel equipped with a mechanical ventilation. The behavior of hot air was studied for the emergency operation mode of ventilation system in case of fire in the rescue station. The 1D simulation was carried out for entire tunnel region. Detailed 3D CFD simulation was performed for the rescue station area in the central region of the tunnel by using the result of the 1D simulation as the boundary condition of the 3D simulation. Various type of cross passage installation were evaluated for the prevention of smoke diffusion to suggest the optimized interval of the cross passages in the rescue tunnel.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.4
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• pp.394-404
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• 2020

Objectives: The aims of this study are to derive the characteristics of diesel exhaust gas emissions generated during vehicle checking in the garage of fire stations and of the related improvement plans for proper air quality management. Methods: The researcher measured changes in the air quality inside garages according to the operating conditions of the exhaust facility and before and after vehicle checking at three fire stations. Results: During the checking of fire engines, a large volume of hazardous substances exceeding management standards were generated, and improvement of the discharge facilities was required for proper air quality management. Conclusions: It is necessary to study the hazard evaluation of firefighters' exposure to exhaust gas, to operate exhaust gas ventilation facilities, and to prepare technical standards for proper indoor air quality management.

• 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 computational fluids engineering
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• v.14 no.3
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• pp.115-122
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• 2009

Numerical methods are applied to simulate the smoke behavior in a ventilated tunnel using large eddy simulation (LES) which is incorporated in FDS (Fire Dynamics Simulator) with proper combustion and radiation model. In this study, present numerical results are compared with data obtained from experiments on pool fires in a ventilated tunnel. The model tunnel is $182m(L){\times}5.4m(W){\times}2.4m(H)$. Two fire scenarios with different ventilation rates are considered with two different fire strengths. The present results are analyzed with those from LES without combustion and radiation model and from RANS ($\kappa-\epsilon$) model as well. Temperature distributions caused by fire in tunnel are compared with each other. It is found that thermal stratification and smoke back-layer can be predicted by FDS and the temperature predictions by FDS show better results than LES without combustion and radiation model. The FDS solver, however, failed to predict correct flow pattern when the high ventilation rate is considered in tunnel because of the defects in the tunnel-inlet turbulence and the near-wall turbulence.

• Tunnel and Underground Space
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• v.15 no.1 s.54
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• pp.55-60
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• 2005

In this study, the 1/20 reduced-scale experiments using Froude scaling were conducted to investigate the effect of longitudinal ventilation on the variation of burning rate in tunnel fires. The methanol square pool fires with heat release rate ranging from 3.57 kW to 10.95 kW were used. The burning rate of fuel was obtained by measured mass using load cell and temperature distribution were measured by K-type theomocouples in order to investigate smoke movement. The wind tunnel was connected with one side of the tested tunnel, and logitudinal ventilation velocity in the tested tunnel was controlled by power of the wind tunnel. In methanol fire case, the increase in ventilation velocity decreased the turning rate due to the direct cooling of fire plume. For the same dimensionless velocity(V), homing rate decreased as the size of pool fire increased.

• 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.

• Fire Science and Engineering
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• v.18 no.1
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• pp.13-17
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• 2004

Purpose: The purpose of this study is to predict a reasonable direction to design a pertinent educational program in the future by evaluating an adult CPR(Cardiopulmonary Resuscitation) skill performed by EMTs engaged in fire services organization and comparing the CPR success rate of factors as like a duty place and licensed year. Methods: We studied CPR skill by the use of a CPR manikin(Skillmeter Resusci Annie, Laerdal company). The study population consisted of 320 EMTs. Every EMT performed four cycle after investigating the manikin for 2 minutes. We regarded chest compression with 100 times in a minute as the 100% success rate. We analysed the skill of chest compression, ventilation and chest compression times success rate by the records printed in the CPR paper. Results: The average success rate of chest compression was 59.42$\pm$29.26% and ventilation 49.22$\pm$29.65%. The success rate of manual CPR was different between chest compression and ventilation. Also the success rate of chest compression times was high relatively as a 87.32$\pm$9.14%(p=0.000). For the CPR skill, ventilation was lowest as 49.22%. The factors such as duty place and licensed year did not influence the CPR success rate (p>0.001). Conclusion: We could have conclusion that CPR training should be shared more time in ventilation than in chest compression. Also we could reach to a conclusion that it is important to increase the times of CPR training for improving the accuracy of CPR and that the continuing education of CPR training frequency might be more than four times in a year.

• Fire Science and Engineering
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• v.23 no.5
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• pp.117-124
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• 2009

The objective of this research is to analyze the ventilation performance of mechanical ventilation systems to enhance removal efficiency of indoor hamful gases. The ventilation performance is evaluated using a step-down method based on ASTM Standard E741-83. The ventilation performance is evaluated as a function of the ventilation rate and supply/extract locations using a tracer gas ($CO_2$) technique. As a result, the $CO_2$ concentration as a function of time is decayed exponentially and the ventilation performance is found to increase with increased the ventilation rate. The ventilation performance of the second type ventilation system is better than that of the first type or the third type. The ventilation performance without human occupancy increases up to 55% and the ventilation performance with one person increases up to 25% at the supply air of 570Lpm comparing with a natural reduction after one hour in the test chamber. The ventilation performance is better than 15% comparing with natural decay at the supply of 570Lpm in an office room.

• Fire Science and Engineering
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• v.31 no.3
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• pp.88-96
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• 2017

The subway can transport a lot of people at a certain route at once, and the railway and the platform are underground, so it is advantageous to use the ground space efficiently. But If a fire occurs in a subway that is used by an unspecified number of people, such as the Daegu Subway Fire Disaster, many casualties can occur. As a result of the previous research, it was confirmed that the performance of the ventilation system of the old subway platform was remarkably degraded. Therefore, in this study, based on the experimental results of the previous research, we confirmed the flow of the hot and CO flows according to the ventilation mode in the case of fire by three - dimensional numerical analysis. As a result, it was found that the old ventilation system could not maintain the hot air temperature below the reference value for 4 minutes based on the evacuation time of the platform, and when the ventilation performance was enhanced by adding Oversized Exhaust Ports at the upper part of the platform, And the temperature of the heat flow can be maintained.

• Journal of Korean Tunnelling and Underground Space Association
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• v.5 no.4
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• pp.389-400
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• 2003

In order to recommend the mechanical smoke exhaust operation mode, Subway Environmental Simulation (SES) is used to predict the airflow of the inlet and outlet tunnel for the subway station. Fire Dynamic Simulation (FDS) is used the SES's velocity boundary conditions to clarity the smoke exhaust effectiveness by the variations with mechnical ventilation system. We compared each 6 types of smoke exhaust systems for the result of smoke density and temperature distributions for 1.5m height from the subway station base in order to clarify the safety evaluation for the heat and smoke exhaust on subway fire.