• Journal of the Korean housing association
• /
• v.17 no.2
• /
• pp.135-142
• /
• 2006

The purpose of this study is to obtain the fire safety for underground commercial space with analysing fire loads and ventilation factors. It was adopted the investigation method of field survey with commercial uses for more confidential data. The results of this study can be summarized as follows; 1) The ventilation factor shows $0.04{\sim}0.24m^{1/2}$ and it may develop ventilation-controlled fires which have much fire hazard more than fuel-controlled fires. 2) The highest value of fire load is $158.48kg/m^2$ and appeared in footwear shop which has the value $137.35kg/m^2$ for unfixed combustibles and $21.13kg/m^2$ for fixed combustibles. 3) The average value of burning rates which mean the velocity of fire development and the fire damage range is 0.143. Therefore it is desired to decrease the combustibles of compartment and is needed the method of dispersion arrangement of goods and storage to steel cabinet and so on.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 2008.11a
• /
• pp.356-362
• /
• 2008

This study is intended to evaluate the characteristics of smoke spreading and the appropriateness of evacuation time extended by operation of smoke control system during fire within the underground space of the building structured in compliance with the smoke control system performance criteria from the local fire safety standard in Korea. As a preceding review of this study, the combustibles was categorized and identified their heat release rates. For validate the estimated values, modeling a single underground shop was carried out. And a numerical analysis both in case of smoke control system in operation and the system not in operation was carried out of underground space. From the viewpoint of securing the evacuation time, the results were compared in an attempt to assess the appropriateness of the fire safety criteria.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.12
• /
• pp.320-330
• /
• 2020

Fire is difficult to achieve good performance in image detection using deep learning because of its high irregularity. In particular, there is little data on fire detection in underground utility facilities, which have poor light conditions and many objects similar to fire. These make fire detection challenging and cause low performance of deep learning models. Therefore, this study proposed a fire detection model using deep learning and estimated the performance of the model. The proposed model was designed using a combination of a basic convolutional neural network, Inception block of GoogleNet, and Skip connection of ResNet to optimize the deep learning model for fire detection under underground utility facilities. In addition, a training technique for the model was proposed. To examine the effectiveness of the method, the trained model was applied to fire images, which included fire and non-fire (which can be misunderstood as a fire) objects under the underground facilities or similar conditions, and results were analyzed. Metrics, such as precision and recall from deep learning models of other studies, were compared with those of the proposed model to estimate the model performance qualitatively. The results showed that the proposed model has high precision and recall for fire detection under low light intensity and both low erroneous and missing detection capabilities for things similar to fire.

• Journal of the Society of Disaster Information
• /
• v.18 no.4
• /
• pp.922-929
• /
• 2022

Purpose: The purpose of this paper is to develop a deep learning model to detect fire extinguishers in images taken from CCTVs in underground utility tunnels. Method: Various fire extinguisher images were collected for detection of fire extinguishers in the running-based underground utility tunnel, and a model applying the One-stage Detector method was developed based on the CNN algorithm. Result: The detection rate of fire extinguishers photographed within 10m through CCTV video in the underground common area is over 96%, showing excellent detection rate. However, it was confirmed that the fire extinguisher object detection rate drops sharply at a distance of 10m or more, in a state where it is difficult to see with the naked eye. Conclusion: This paper develops a model for detecting fire extinguisher objects in underground common areas, and the model shows high performance, and it is judged that it can be used for underground common area digital twin model synchronizing.

• Fire Science and Engineering
• /
• v.17 no.4
• /
• pp.57-63
• /
• 2003

In this study; the evaluation system models for evacuation safety assessment of underground malls were presented and related software program was developed. In addition, database was built integrating various data which were essential to evacuation safety assessment and enabling effective safety assessment with low cost and time. As a results of case study in local underground malls, the evacuation safety assessment system has examined in therms of field applicability and reliability.

• Tunnel and Underground Space
• /
• v.20 no.2
• /
• pp.92-96
• /
• 2010

In this study, experiments were conducted to evaluate the effectiveness of ventilation equipment in underground fires. Two type of Ventilators were used in experiments. Experiments were carried out using ethanol square pool fire. Maximum heat release rate was about 460kW. Visibility and temperature distribution were evaluated according to mechanical ventilation. In blower type ventilation, visibility was increased and temperature was lowered.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.1
• /
• pp.21-26
• /
• 2015

This study represents the effective fire and smoke control in the case of fire in deep underground tunnels, even if the exhaust system can be calculated, the optimal smoke capacity can be determined by establishing technical standards for the transverse ventilation system focusing on the design as a basis for deriving the parameters for utilization. Numerical analyses were performed using the FDS program as a function of the unsteady flow in a deep underground tunnel fire. The analysis results were calculated within 250 m smoke using an inside wind velocity of 0m/s when the capacity of smoke was exhausted, $80m^3/s$, whereas in case of an internal wind velocity of 3m/s, the capacity of smoke exhaust was $197.1m^3/s$, showing an approximately 2.5 fold increase.

• Fire Science and Engineering
• /
• v.16 no.2
• /
• pp.75-80
• /
• 2002

In this paper, some experiments of a heat release rate and toxicity for underground utility 22.9kv cable in fire was conducted and analysed applying plume equation and smoke chamber test separately, A 22.9 ㎸ power cable is selected for testing heat release in ISO 9705 geometry and toxicity production is measured with NES 713 (British-Naval Engineering Standard)test. In test results, Cable heat release reached about 60 ㎾ above 1.2 m from heptane pan and CO generated lethal concentration under 30 min. exposure condition.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.15 no.10
• /
• pp.821-827
• /
• 2003

Reduced-scale experimental study was carried out on the heat flow behavior which flows under the sloped ceiling in underground fire. Temperature and flow velocity were measured to characterize the ceiling jet along the sloped stairway ceiling. The methanol fuel was used as a model fire source giving 2.2 and 3.4 kW, with changing the slope angle of stairway adopting of 15, 25, 35, and 45 deg. Based on the experimental data, excess temperature and velocity along the sloped stairway ceiling were examined which are usefully applicable to estimate the activating conditions of heat detector and sprinkler head mounted on the sloped ceiling. Excess temperature in upper exit of the sloped stairway was also examined to analyze the soffit which delays the smoke diffusion. The result shows that the activating conditions of heat detector and sprinkler in the sloped stairway ceiling have to be considered differently in a point of about 30 deg.

• Fire Science and Engineering
• /
• v.16 no.2
• /
• pp.70-74
• /
• 2002

This study suggests safety assessment items and risk assessment technique for underground shopping malls by extracting dangerous elements in the management stage through examination of related accidents, documents and present conditions.