• Title/Summary/Keyword: fire effects

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The Effects of Firefighters' Experience of Trauma and Forest Walks on Burnout (소방공무원의 외상사건 경험 및 산림산책이 소진에 미치는 영향)

  • Shin, Sun-Hee;Kong, Ha-Sung
    • Journal of the Korea Safety Management & Science
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    • v.22 no.2
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    • pp.57-71
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    • 2020
  • The purpose of this study is to explore the effects of fire officers' experience of traumatic events and subsequent forest healing on their occupational burnout. The results are as follows: First, the experience of traumatic events, social and psychological healing, and relieving stress by strolling had a significant effect on burnout. The more fire officers are exposed to traumatic events, the more they lose self-control in social and psychological aspects, and the lower the level of stress relieved through strolling, the higher the level of burnout. Thi sresult suggests that the more fire office rsare called out for fire fighting, the more they see their colleagues with severein juries, and the higher the level of mental and physical an xiety, the more they areex hausted. Moreover, for es thealing help store duce the irmental and physi calfatig uecaused by traumatic events, thu spreven ting them from suffering from burn out. Second, the experience of traumatic events, social and psychological healing, and relieving stress by strolling had a significant impact on occupational stress. The more fire officers are exposed to traumatic events, the more they lose self-control in social and psychological aspects, and the lower the level of stress relieved through strolling, the higher the level of occupational stress. This result indicates that to relieve job stress caused by fire fighting, increased forest healing activities, including various programs such as psychotherapy, developing interpersonal relationships and self-control, and creating a positive mind-set, can reducejobstress and help fire officers recover from it. Lastly, job stress had a mediation effect on the effects of the experience of traumatic events and forest healing on burnout. This implies that burnout can be prevented when fire officers gain high emotional stability through social and psychological healing and stress-relief strolling over a traumatic experience, and stronger support from the organization and family can keep them from being emotionally drained, thus contributing to the prevention of burnout.

Normalized Difference Vegetation Index based on Landsat Images Variations between Artificial and Natural Restoration Areas after Forest Fire (산불 지역 인공·자연복원에 따른 Landsat영상 기반 식생지수 비교)

  • Noh, Jiseon;Choi, Jaeyong
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.25 no.5
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    • pp.43-57
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    • 2022
  • This study aims to classify forest fire-affected areas, identify forest types by the intensity of forest fire damage using multi-time Landsat-satellite images before and after forest fires and to analyze the effects of artificial restoration sites and natural restoration sites. The difference in the values of the Normalized Burned Ratio(NBR) before and after forest fire damage not only maximized the identification of forest fire affected and unaffected areas, but also quantified the intensity of forest fire damage. The index was also used to confirm that the higher the intensity of forest fire damage in all forest fire-affected areas, the higher the proportion of coniferous forests, relatively. Monitoring was conducted after forest fires through Normalized Difference Vegetation Index(NDVI), an index suitable for the analysis of effects by restoration type and the NDVI values for artificial restoration sites were found to no longer be higher after recovering the average NDVI prior to the forest fire. On the other hand, the natural restoration site witnessed that the average NDVI value gradually became higher than before the forest fires. The study result confirms the natural resilience of forests and these results can serve as a basis for decision-making for future restoration plans for the forest fire affected areas. Further analysis with various conditions is required to improve accuracy and utilization for the policies, in particular, spatial analysis through forest maps as well as review through site checks before and immediately after forest fires. More precise analysis on the effects of restoration will be available based on a long term monitoring.

Numerical Study on the Effects of Spray Properties of Water Mist on the Fire Suppression Mechanism (미분무수 특성이 화재억제 메커니즘에 미치는 영향에 대한 수치해석적 연구)

  • Bae, Kang-Youl;Chung, Hee-Taeg;Kim, Hyoung-Bum
    • Journal of ILASS-Korea
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    • v.22 no.4
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    • pp.175-184
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    • 2017
  • The numerical investigation on the effects of water-mist characteristics has been carried out for the fire suppression mechanism. The FDS are used to simulate the interaction of fire plume and water mists, and program describes the fire-driven flows using LES turbulence model, the mixture fraction combustion model, the finite volume method of radiation transport for a non-scattering gray gas, and conjugate heat transfer between wall and gas flow. The numerical model is consisted of a rectangular enclosure of $L{\times}W{\times}H=1.5{\times}1.5{\times}2.0m^3$ and a water mist nozzle that be installed 1.8 m from fire pool. In the present study, the parameters of nozzle for simulation are the droplet size and the spray velocity. The droplet size influences to fire flume on fire suppression more than the spray velocity because of the effect of the terminal velocity. The optimal condition for fire suppression is that the droplet size and the spray velocity are $100{\mu}m$ and 20 m/s respectively.

Methodology for investigating the behavior of reinforced concrete structures subjected to post earthquake fire

  • Behnam, Behrouz;Ronagh, Hamid R.;Baji, Hassan
    • Advances in concrete construction
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    • v.1 no.1
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    • pp.29-44
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    • 2013
  • Post earthquake fire (PEF) can lead to the collapse of buildings that are partially damaged in a prior ground-motion that occurred immediately before the fire. The majority of standards and codes for the design of structures against earthquake ignore the possibility of PEF and thus buildings designed with those codes could be too weak when subjected to a fire after an earthquake. An investigation based on sequential analysis inspired by FEMA356 is performed here on the Life-Safety performance level of structures designed to the ACI 318-08 code after they are subjected to two different earthquake levels with PGA of 0.35 g and 0.25 g. This is followed by a four-hour fire analysis of the weakened structure, from which the time it takes for the weakened structure to collapse is calculated. As a benchmark, the fire analysis is also performed for undamaged structure and before occurrence of earthquake. The results show that the vulnerability of structures increases dramatically when a previously damaged structure is exposed to PEF. The results also show the damaging effects of post earthquake fire are exacerbated when initiated from second and third floor. Whilst the investigation is for a certain class of structures (regular building, intermediate reinforced structure, 3 stories), the results confirm the need for the incorporation of post earthquake fire in the process of analysis and design and provides some quantitative measures on the level of associated effects.

Numerical Investigation on Fire of Stage in Theater: Effects of Natural Smoke Vent Area and Fire Source Location (공연장 무대부 화재에 대한 전산해석 연구: 자연 배연구 면적과 화원 위치 영향)

  • Park, Min Yeong;Lee, Chi Young
    • Journal of the Korean Society of Safety
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    • v.37 no.1
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    • pp.1-11
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    • 2022
  • This numerical study investigates the effects of the size of the natural smoke vent area (10% and 1% of the floor area) and the location of the fire source (i.e., at the side and center of the stage) on the temperature distribution in the compartment and velocity distribution and mass flow rate of flow through a natural smoke vent for a reduced-scale model of a theater stage. Then, the mass flow rate of outflow through the natural smoke vent in the event of a fire for a real-scale theater stage was examined. The case with the larger natural smoke vent area and central fire source location showed lower temperature distributions and higher mass flow rates of outflow and inflow than the case with the smaller natural smoke vent area and side fire source location. The trends of the temperature distributions were closely related to those of the mass flow rates for the outflow and inflow. Additionally, the case with the larger natural smoke vent area and central fire source location exhibited the most non-uniform flow velocity distribution in all cases tested. A bidirectional flow, in which the outflow and inflow occur simultaneously, was observed through the natural smoke vent. In the event of a fire situation in a real-scale theater stage, it was predicted that the case with the larger natural smoke vent area and central fire source location would have a mass flow rate of outflow that is 43.53 times higher than that of the case with the smaller natural smoke vent area and side fire source location. The present results indicate that the natural smoke vent location should be determined by considering the location in a theater stage where a fire can occur.

Researches on Fire in Traditional Chinese Medicine (중의학(中医学) "화(火)" 더변석(的辨析))

  • Li, Hai-Yu;Pan, Gui-Juan
    • Journal of Korean Medical classics
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    • v.22 no.4
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    • pp.255-259
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    • 2009
  • The origin of "Fire" in Traditional Chinese Medicine is summed up based on observation and knowledge of natural fire, followed by abstract thinking, of which the outcomes are best symbolized in the character Fire[火]. Because it is an abstract concept, it is hard to give a single and strict definition. Naturally, it would be necessary to analyze and illustrate the origin of 'Fire' from different angles such as broad definition, multi-definition, levels, classifications and effects. The concept of 'Fire' has four meanings in the aspect of the broad definition: first, natural fire; second, the physiological conception of fire; third, the medical conception of fire; fourth, general concept related to fire. In Traditional Chinese Medicine, fire mainly indicates physiologic fire, pathological fire, the fire in the six kinds of natural climate and the fire as one of the properties and the flavors of herbs.

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Post-earthquake fire performance-based behavior of reinforced concrete structures

  • Behnama, Behrouz;Ronagh, Hamid R.
    • Earthquakes and Structures
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    • v.5 no.4
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    • pp.379-394
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    • 2013
  • Post-earthquake fire (PEF) can lead to a rapid collapse of buildings damaged partially as a result of prior earthquake. Almost all standards and codes for the design of structures against earthquake ignore the risk of PEF, and thus buildings designed using those codes could be too weak when subjected to a fire after an earthquake. An investigation based on sequential analysis inspired by FEMA356 is performed here on the Immediate Occupancy, Life Safety and Collapse Prevention performance levels of structures, designed to the ACI 318-08 code, after they are subjected to an earthquake level with PGA of 0.35g. This investigation is followed by a fire analysis of the damaged structures, examining the time taken for the damaged structures to collapse. As a point of reference, a fire analysis is also performed for undamaged structures and before the occurrence of earthquake. The results indicate that the vulnerability of structures increases dramatically when a previously damaged structure is exposed to PEF. The results also show that the damaging effects of post-earthquake fire are exacerbated when initiated from the second and third floor. Whilst the investigation is made for a certain class of structures (conventional buildings, intermediate reinforced structure, 3 stories), the results confirm the need for the incorporation of post-earthquake fire into the process of analysis and design, and provides some quantitative measures on the level of associated effects.

Study on the Ejected Plume from Opening Regarding Side-wall Effect in Fire (측벽효과를 고려한 개구부 분출화염 거동 연구)

  • Jeong, Jae-Gun;Shin, Yi-Chul
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2016.05a
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    • pp.219-220
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    • 2016
  • The behavior of fire plumes has not yet been clearly identified for cases where sidewalls are installed near an opening in an unconfined space. In this research, we aim to quantitatively identify the effects on fire spread when sidewalls are located on both sides of an opening. Specifically, we focus on the effects on the fire plume of the relation between the location of sidewalls and the opening, and carry out a scale-model experiment to devise a flame height model and to evaluate the temperature distribution along the central axis of the flame.

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