• Fire Science and Engineering
• /
• v.31 no.6
• /
• pp.23-32
• /
• 2017

Foam block, popularized as the self-interior goods, is susceptible to fire since the main material is the polyethylene flammable synthetic resin. However, it is widely used in homes, offices, and multi-use facilities. In order to understand the fire characteristics of the foam block, two kinds of foam blocks sold in the market (non-fire retardant and fire retardant) were evaluated according to standard of KS F 5660-1 (Reaction to fire test). In addition, the hazard analysis of the gas generated by the combustion of the specimen was performed using the FTIR gas analyzer. The cone calorimeter test showed that the ignition and flame combustion of both two specimens were burned as soon as the radiant heat blocking device was removed, and it was confirmed that the flame could become a rapid propagation factor during the fire. The analysis of the combustion gas through the FTIR gas analyzer showed that both the carbon dioxide and carbon monoxide classified as the common combustion gases and the acrolein, ammonia, and hydrogen cyanide causing serious damage to the human body were detected substantially. This study showed that a foam block product has high ignitionability and generates toxic gases. Hence, it is urgently required to establish the standards used for properly classifying the combustion characteristics of the material on the basis of the use conditions of a foam block product and to prepare the standards on the purpose of use.

• Journal of the Korea Society of Computer and Information
• /
• v.16 no.6
• /
• pp.21-30
• /
• 2011

In the global IT market, a lot of issues for responding to various environmental regulations emerged. In case of the data centers, it is consuming huge amounts of energy to maintain. So there have been various technical attempts as Consolidation, Virtualization, Optimization to efficiently manage energy and data storage to fix the problems. In this paper, we propose a new RAID(Redundant Array of Independent Disks) mechanism which is differing the intensity of power consumption and works to provide data protection and disaster recovery(backup, mirroring etc.) to stratify multiple volumes. G-RAID minimize the power consumption and the lower of I/O performance by selecting the volume depending on the frequency of data access while classifying the power consumption between volumes in storage system. Also, it is possible that a filesystem and block map information of G-RAID is processed by basic unit which is group located in a row for the blocks to work efficiently and can minimize the performance degradation of block mapping load by the access frequency in each groups. As a result, we obtained to elevate a little bit of response time caused by block relocation work, but showed the decrease of power consumption by 38%.

• Journal of the Society of Disaster Information
• /
• v.9 no.4
• /
• pp.449-461
• /
• 2013

As the hydrofluoric acid leak in Gumi-si, Gyeongsangbuk-do or hydrochloric acid leak in Ulsan, Gyeongsangnam-do demonstrated, chemical related accidents are mostly caused by large amounts of volatile toxic substances leaking due to the damages of storage tank or pipe lines of transporter. Safety assessment is the most important concern because such toxic material accidents cause human and material damages to the environment and atmosphere of the surrounding area. Therefore, in this study, a hydrofluoric acid leaked from a storage tank was selected as the study example to simulate the leaked substance diffusing into the atmosphere and result analysis was performed through the numerical Analysis and diffusion simulation of ALOHA(Areal Location of Hazardous Atmospheres). the results of a qualitative evaluation of HAZOP (Hazard Operability)was looked at to find that the flange leak, operation delay due to leakage of the valve and the hose, and toxic gas leak were danger factors. Possibility of fire from temperature, pressure and corrosion, nitrogen supply overpressure and toxic leak from internal corrosion of tank or pipe joints were also found to be high. ALOHA resulting effects were a little different depending on the input data of Dense Gas Model, however, the wind direction and speed, rather than atmospheric stability, played bigger role. Higher wind speed affected the diffusion of contaminant. In term of the diffusion concentration, both liquid and gas leaks resulted in almost the same $LC_{50}$ and ALOHA AEGL-3(Acute Exposure Guidline Level) values. Each scenarios showed almost identical results in ALOHA model. Therefore, a buffer distance of toxic gas can be determined by comparing the numerical analysis and the diffusion concentration to the IDLH(Immediately Dangerous to Life and Health). Such study will help perform the risk assessment of toxic leak more efficiently and be utilized in establishing community emergency response system properly.

• Journal of Korean Society of Disaster and Security
• /
• v.10 no.2
• /
• pp.7-19
• /
• 2017

Recently, the incidence of disasters and safety incidents is increasing rapidly, and the interest and demands of the people are increasing. In particular, traffic accidents in Korea are decreasing due to the continuous efforts of the government and the local governments, but still higher than the OECD average. In response to such demands of the times, the 'Regional Safety Index', a numerical value that quantifies the level of safety of each local government, is being publicized every year to awaken public awareness. The Regional Safety Index covers seven categories of accidents (traffic accidents, crimes, suicide, infectious diseases, fire, safety accidents, and natural disasters) in local governments. But, this study focuses on the traffic accident area and analyzed. The target local government is Ulju county of Ulsan Metropolitan City. Based on the traffic accident statistical data of Ulju county, the analysis of the traffic accidents and vulnerable points were analyzed. Among them, 3 key improvement districts were selected and 15 vulnerable branches were selected for each key improvement district. Next, we prepared measures for improvement of each accident vulnerable site through analysis of geographic information through traffic data related to traffic accidents and interview with related organizations. In addition, the improvement measures are divided into the structural infrastructure improvement, the institutional improvement, and the traffic safety culture movement from the viewpoint of traffic accident prevention. Finally, the implications of this study are to clarify the duties and roles of the relevant departments in the municipality, based on the implementation schedule of the improvement projects for the prevention of traffic accidents and the budget plan. In addition, it is very important that the participating agencies involved in traffic accidents and the private sector participate in the project.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.5
• /
• pp.716-722
• /
• 2017

The present study numerically investigates the effect of obstacles located in the trajectory of fire plume flow on heat flow characteristics by using Fire Dynamics Simulation (FDS) software in an underground combined cycle power plant (CCPP). Fire size is taken as 10 MW and two different locations of fire source are selected depending on the presence of an obstacle. As the results, when the obstacle is in the trajectory of fire plume, hot plume arrives at the ceiling about 5 times slower in the upper of the fire in comparison to the results without obstacle. In addition, the average propagation time of ceiling jet increases by about 70 % with the distance from the ceiling in the upper of the fire, and it increases mainly about 4 times at the distance of 10 m. Consequently, it is noted that the analysis of heat flow characteristics in the underground CCPP considering fire scenarios is essential to develop the fire detection system for initial response on evacuation and disaster management.

• Health Policy and Management
• /
• v.16 no.4
• /
• pp.48-67
• /
• 2006

The aim of the study was to examine levels of satisfaction with health care in North Korea and to identify factors associated with it using a convenience sample of North Korean refugees in China. Data from the 2004 Survey of Health Seeking Behavior of North Korean Households conducted by the Center for Refugee and Disaster Response, Johns Hopkins Bloomberg School of Public Health were used. The study subjects were 273 North Korean refugees whose length of stay in China was less than 3 months. Factor analysis was used to extract factor dimensions from the 12 satisfaction items. Bivariate (t test and ANOVA) and multiple regression analyses were used in examining factors associated with satisfaction with health care use in North Korea Overall, satisfaction level was low ($2.36{\pm}0.36$, score range: 1-5). Of the three-factor dimensions, physician skills scored the highest $(2.93{\pm}0.36)$, followed by drug availability $(2.51{\pm}0.07)$ and general cleanliness $(1.66{\pm}0.55)$. In the multiple regression analysis, having a usual source of care was significantly associated with patient satisfaction. Respondents who identified primary care (section) doctors as their usual source of care tended to be less satisfied than those with the city or county hospital as their usual source of care. County residents tended to report a lower degree of satisfaction with general cleanliness than city residents. Among socioeconomic characteristics, the number of household assets positively predicted satisfaction with drug availability. North Korean residents appear to be dissatisfied with their medical care. It may reflect some inadequacies in the North's universal health care system to meet the healthcare needs of its people.

• International Journal of High-Rise Buildings
• /
• v.9 no.2
• /
• pp.127-154
• /
• 2020

Disproportionate collapse triggered by local structural failure may cause huge casualties and economic losses, being one of the most critical civil engineering incidents. It is generally recognized that ensuring robustness of a structure, defined as its insensitivity to local failure, is the most acceptable and effective method to arrest disproportionate collapse. To date, the concept of robustness in its definition and quantification is still an issue of controversy. This paper presents a detailed review on about 50 quantitative measures of robustness for building structures, being classified into structural attribute-based and structural performance-based measures (deterministic and probabilistic). The definition of robustness is first described and distinguished from that of collapse resistance, vulnerability and redundancy. The review shows that deterministic measures predominate in quantifying structural robustness by comparing the structural responses of an intact and damaged structure. The attribute-based measures based on structural topology and stiffness are only applicable to elastic state of simple structural forms while the probabilistic measures receive growing interest by accounting for uncertainties in abnormal events, local failure, structural system and failure-induced consequences, which can be used for decision-making tools. There is still a lack of generalized quantifications of robustness, which should be derived based on the definition and design objectives and on the response of a structure to local damage as well as the associated consequences of collapse. Critical issues and recommendations for future design and research on quantification of robustness are provided from the views of column removal scenarios, types of structures, regularity of structural layouts, collapse modes, numerical methods, multiple hazards, degrees of robustness, partial damage of components, acceptable design criteria.

• Journal of Korean Society of Steel Construction
• /
• v.29 no.1
• /
• pp.49-60
• /
• 2017

As well as the strength check, fatigue life check is also mainly required for designing mooring lines of the floating structures. In general, forces which induce dynamic structural response significantly affect to fatigue design of the mooring lines. So, waves are mainly considered as the governing loading for fatigue design of the mooring lines. In this study, characteristics of the fatigue damage of the mooring lines for submerged floating tunnels (SFT) under irregular waves are investigated. For this study time domain hydrodynamic analysis is used to obtain motion of the tunnel and tension and stresses of the mooring lines under the specific environmental conditions. Also, the Rainflow-counting method, the Palmgren-Miner's rule, and S-N curves for floating offshore structures presented by DNV recommendation is applied to calculate the fatigue damage due to the fluctuating stresses. Referring to the design plactice of the tendon pipes for TLP (tension-leg platform), which is very similar structural system to SFT, it is assumed that a 100 year return period wave attacks the SFT systems during 48 hours and the fatigue damages due to the environmental loading are calculated. Following the analysis sequence, the effects of the tunnel draft, spacing and initial inclination angle of the mooring lines on the fatigue damage under the specific environmental loadings are investigated.

• Fire Science and Engineering
• /
• v.30 no.6
• /
• pp.48-56
• /
• 2016

A crude oil leakage from a large atmospheric storage tank occurred on 4 April 2014 at 14:50 in Ulsan City, while storing the crude oil in the tank. Emergency Rescue Control Group was deployed in the scene. The company, Fire Service Headquarters and associated agencies got together in Command Post (CP) for discussing an effective corresponding strategy. Many solution plans were drafted in the debate such as power down, stopping the facilities, checking the density of inflammable gas, suppressing oil evaporation, moving the leaked crude oil to a nearby tank and a processing plant and avoiding marine pollution. All the solutions were carried out in cooperation with several agencies and partners. The oil leakage accident was successfully settled up within the process of responding, The Fire Service Headquarters and the company thought that the most important thing was the suppression of oil evaporation and the elimination of ignition source. With Fire Service Headquarters and several agencies' every effort, an explosion and a fire didn't occurred in the scene. This study suggest the improvement of the operating system in Emergency Rescue Control Group in case of petroleum leakage, explosion and fire accidents of atmospheric storage tank, different from a ordinary disaster. Assuming that petroleum leakage in atmospheric storage tank develop the explosion and fire accidents, the spreading speed of the flame and the burning time was experimented and compared with each other. Furthermore, this study concentrates on the effective field response plan prepared for the afterward explosion and fire accidents from petroleum leak in a storage tank, with the database experimented and analyzed in accordance with the angle of radiation in the foam nozzle and the pressure of pumping in a fire engine.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.22 no.3
• /
• pp.745-753
• /
• 2021

Recently, a large fire occurred in a multi-use facility used by a large number of citizens, including the vulnerable, resulting in a lot of injuries and damages. Although several pilot studies have been conducted to reduce such incidents, the development of advanced disaster response technology using the latest spatial information and IoT technology is still insufficient. In this study, a pilot test bed is built to demonstrate detailed technologies derived through the first stage of realistic fire management technology research for the development of applied technology in the field. In detail, the building conditions and candidate sites of the test bed were first investigated and analyzed to derive satisfactory conditions and candidate target buildings. A second pilot test bed was then selected, and the necessary sensor and facility infrastructure were built to demonstrate the outcomes. Finally, a scenario was produced for technology verification, and a test bed system was developed. The pilot test bed is expected to contribute to verifying intermediate outcomes of realistic fire management research projects, enhancing the quality of the developed technologies.