• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.5
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• pp.128-134
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• 2014

Recently, design and construction of street tunnels tend to focus on cost reduction and preservation of nature. Accordingly, research is actively being carried out to quickly detect fires when they occur in tunnels, which have partially closed structures. Among such research, fire detection methods using optical fiber sensors have a wide bandwidth and fast transmission speed, while using light as a medium. Therefore, it does not receive electrical interference and there is almost no loss of information during transmission, while also having little noise as well. In relation to this, a fire monitoring system that can accurately detect the location of fires in real time using shape memory alloy and optical cables was developed in this study. In order to verify the developed method, light loss measurement test was conducted according to indoor temperature changes, while also conducting fire simulation tests by installing test beds in common underground zones with different external environments of temperature and distance. Upon carrying out experiments, the fire monitoring system developed in this study was found to be able to detect fires in long distance sections in real time.

• Journal of the Korean Institute of Gas
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• v.26 no.4
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• pp.18-26
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• 2022

The Korean government is conducting heat-using equipment(industrial boiler) inspection in accordance with the Energy Use Rationalization Act because of the heat-using equipment(industrial boiler)'s risks such as explosion and fire, and safe use and management. This paper aimed to setup the safe and performance vulnerabilities from database based on the inspection results for heat-using equipment(industrial boiler). This study surveyed the inspection results of 1,249 heat-using equipment(industrial boiler) which were failed inspection of heat-using equipment(industrial boiler) from january 2016 to december 2020. And the analysis method is to inform safety and performance vulnerability categories of heat-using equipment(industrial boiler) by statistically analyzing the failure reasons of boiler type and inspection type which are high variance in failure rate. The safety and performance vulnerability categories was abbreviated into 18 cases. And each catagory's main reason for failure was suggested by additional analyzing the opinions of inspectors. This paper would be the basic source and the comprehensive information dealing with the safety and performance vulnerability of heat-using equipment(industrial boiler).

• Fire Science and Engineering
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• v.33 no.3
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• pp.128-137
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• 2019

The aim of this study was to suggest ways to improve the operation of the Incident Command System for an effective disaster response in the event of a major disaster. As a result of the study, at the 5% significance level, which affects the perception of the operation, the significant variables that influence the operation of the Incidence Command System were found to be securing the operating budget, cooperation of the related agencies, disaster resource support, and expert training. The relative influence of the variables on the operation of the Incident Command System was found to be in the order of expert training, cooperation of related organizations, disaster resource support, and securing of the operating budget.

• Fire Science and Engineering
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• v.20 no.3 s.63
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• pp.21-28
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• 2006

Since hot toxic gas included in the fire is the most principal reason of the death and has the fluid mechanical characteristics unlike air, smoke control method appropriate for the figure and structure of a fire room is needed and each unit of the smoke control system requests high performance according to this characteristics, for which performance test procedures and evaluation criteria must be established. Domestic criteria involved with the smoke control consist of the pre-investigation by documents and the part inspection, which has lots of problems because they are far from the performance based evaluation method compared with the references of developed countries. Consequently, domestic and international references were compared and analyzed, problems being emerged and standardization scheme of the test procedure was presented.

• Fire Science and Engineering
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• v.34 no.3
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• pp.8-17
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• 2020

In this study, the characteristics of HFIX insulated wire sheaths contaminated by pollutants were examined. KS C IEC 60811-1-3 standard was followed in performing the water-resistance wire tests. Pollutants were selected, and the specimens were exposed to the pollutants for a maximum duration of four weeks. The maximum tensile load and the elongation rate were measured each week. As the period of pollution exposure increased, the maximum tensile load of the specimens decreased by 6.22% and 6.52% at room temperature and high temperature, respectively, and 19.94% for specimens coated with a rust-proof lubricant. The elongation rate also decreased rapidly, such that the reductions in the properties of the sheath were significant. From the analysis of the surfaces using a scanning microscope, as the contamination period increased, structural changes such as perforation, split, and melting occurred, and the mechanical properties of the specimens decreased. Therefore, it is necessary to develop and follow an inspection cycle and periodically carry out repairs to prevent the deterioration of insulated wires.

• Fire Science and Engineering
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• v.27 no.6
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• pp.8-14
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• 2013

This research is to evaluate the fire extinguishing performance at a mixing ratio of pressurized air in the fire extinguishing system of compressed air foam (CAF) which injects compressed air into foam liquid and then discharging. The experimental device is made use of exclusive foam extinguishing facility for compressed air foam that is produces based on Canada National Laboratory and UL 162 standard, apply model of oil fire (B Class) 20 unit in accordance with "Standard of Model Approval and Product Inspection for Fire Extinguishing Agent" to the fire Extinguishing model. Compressed air is injected through the air mixture and study the tendency depending on increasing air foam ratio 1 : 4, 1 : 7, 1 : 10. In addition, the comparison experiments between synthetic surfactants foam and AFFF carry out with it at the air foam ratio 1 : 4. As a result, in the condition of same discharging flow, fire extinguishing effect of AFFF is the fastest at the air foam ratio 1 : 7 and the slowest at 1 : 10. Moreover, the fire extinguishing effect of AFFF in the comparison expeiments between AFFF and synthetic surfactants foam is faster than the other.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.2
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• pp.94-100
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• 2013

In this paper, Machinery analysis was conducted, in order to predict highest exposure temperatures and the analyze fire damage in the case of fire on reinforced concrete structure. After analyzing differential thermal of reference materials in accordance with temperature of concrete reference core specimen, it turned out that powerful endothermic peak came resulting from evaporation of capillary water and get water untill $200^{\circ}C$, another endothermic peak came resulting from decomposition of calcium hydroxide at $520^{\circ}C$, and then mass of reference materials remarkably decreased due to endothermic reaction. Another powerful endothermic reaction came after decomposition of calcite at $720^{\circ}C$. After analyzing X-ray diffraction of reference materials in accordance with temperature of concrete reference core specimen, it turned out that calcium hydroxide existed until the temperature of $400^{\circ}C$, but CH almost disappeared and CaO appeared from $600^{\circ}C$. The production increased in proportion to the temperature. This is because that calcium hydroxide and calcite are decomposed and CaO is produced when the temperature of concrete increases with fire. It is estimated that calcium hydroxide and calcite are utterly decomposed and peak disappears, and peak of CaO is remarkably formed instead, at the temperature of $700-800^{\circ}C$.

• Journal of the Korean Society of Safety
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• v.33 no.5
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• pp.170-176
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• 2018

Laboratory inspection and diagnosis is a means of investigating and assessing various hazards or the state of research equipment in a laboratory, then taking appropriate safety measures to prevent accidents and injury. In many cases, laboratory inspection and diagnosis carried out by agencies are performed in a perfunctory manner that only barely satisfies the legal requirements. The aim of the present study is to provide clearly established pricing criteria for laboratory inspection and diagnosis, so as to prevent recurrence of laboratory accidents and to establish a safe laboratory environment. In order to clarify previously unclear matters, such as the lower limit for bids submitted by laboratory inspection and diagnosis agencies, technical manpower requirements, and number of laboratories inspected and diagnosed per day, a questionnaire survey was administered to agency personnel. First, when asked what the lower limit for bids submitted by agencies should be in order to improve reliability of inspection and diagnosis results and make up for the shortcomings of the lowest-bidder-wins system, 85.5% of respondents answered that the lower limit for bids should stand at no lower than 90% of the estimated price. The level of technical expertise among the technical personnel committed to laboratory inspection and diagnosis was shown to impact the reliability of results, and questionnaire results indicated a need to vary technical expertise levels depending on the degree of hazard, substances handled, and equipment used in a given laboratory. Level of technical expertise(67.1%) and number of personnel(52.6%) were shown to have a greater impact on reliability of diagnosis than on reliability of inspection. According to the results, it is determined that three persons(specialist, advanced and intermediate) should be committed to inspections, while four persons(professional, specialist, advanced and intermediate) should be committed to diagnoses. The respondents indicated a larger number of laboratories could be inspected than diagnosed per day. This can be attributed to differences in the amount of work each task involves, and the time each task takes. Assuming a six-hour work day not counting transportation, paperwork and rest, it is thought that inspection of up to 36 laboratories will be possible if each laboratory is assigned no more than 10 minutes(34.7%), while up to 24 laboratories could be inspected and diagnosed if each laboratory is assigned 15 to 20 minutes(35.1%).

• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.2
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• pp.177-183
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• 2004

The maturity concept is based on the fact that concrete gains strength with time as a result of the cement hydration and, thus the strength of concrete is related to the degree of hydration of the cement in concrete. The rate of hydration, as in any chemical reaction, depends primarily on the concrete temperature during hydration. Therefore, the aim of the study is to investigate of the correlation between strength of high-strength concrete and maturity that is expressed as a function of an integral of the curing period and temperature.

• Proceedings of the Korean Society of Computer Information Conference
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• 2015.01a
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• pp.171-173
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• 2015

최근 원격 탐사를 이용한 사람이 탐사하기 어려운 환경을 대신 탐사 할 수 있는 로봇의 필요성이 두각 되고 있다. 그 중에 화재현장 탐사 로봇은 일부 지형의 협소함 탓에 사람의 탐사를 대신하기 위한 목적으로 지속적인 개발이 이루어지고 있다. 이 로봇은 아두이노(Arduino) 보드를 기반으로 하여 현장에 있는 탐사로봇으로 지형에 대한 정보 및 영상을 사용자에게 전송함으로써 사람의 탐사현장 투입을 대체한다. 탐사로봇은 거리가 멀어질수록 혹은 장애물이 많은 공간일수록 통신 신호가 약해지거나 이동의 어려움 때문에 성능저하가 우려된다. 또한 센서 및 모터제어와 영상 송출이 각각의 프로그램을 통해 동작하므로 일일이 실행하여 사용에 번거롭다는 문제가 있다. 이러한 문제점들은 통신 거리가 긴 동글(dongle)을 설치하여 통신장애를 해결하고 캐터필러의 사용으로 이동성을 향상하였다. 마지막으로 여러 프로그램을 하나의 프로그램으로 새로 구현하여 편리성을 높였다.