• Fire Science and Engineering
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• v.31 no.2
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• pp.29-36
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• 2017

The design fire based on the heat release rate (HRR) of combustibles can significantly affect the assessment of fire safety in the performance-based design (PBD). In the present PBD, however, limited information in the foreign literature has been used without further verification due to the lack of fire information in domestic combustibles. The objective of this study is to provide information on the HRR and fire growth rate for various combustibles in residential and office spaces. To end this, the fire experiments were carried out with single and multiple combustibles. The peak HRR of combustibles used in the present study had a range of 36 kW~1,092 kW. The fire growth rates were also $0.003kW/s^2{\sim}0.0287kW/s^2$ and $0.003kW/s^2{\sim}0.0838kW/s^2$ for the residential and office spaces, respectively. In particular, a sofa had the highest fire risk in terms of the peak HRR and fire growth rate. Finally, a methodology for calculating the peak HRR in a space was proposed through correlation analysis between the peak HRR and exposed surface of various combustibles.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.76-83
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• 2021

This study examines the bending behavior of lap-spliced ultra-high-strength fiber-reinforced concrete members and evaluates the safety of the design codes for ultra-high-strength fiber-reinforced concrete structures. An experiment on a total of six beams was performed. The main variables were the fiber-inclusion and the lap-spliced length at the center of the beams. The steel fibers in a volume fraction of 2% were used, and the lap-splice lengths were determined to be 8db and 16db. As a result of the test, the specimens not reinforced with fiber lost abrupt load-bearing capacity at the lap region and did not experience yielding of the reinforcing bar. In the case of fiber-reinforced concrete, if a lap-splice length of 16db is secured, the yielding of the main reinforcing bar can be experienced, and appropriate flexural strength can be expressed. Based on the experimental results of this study, as a result of reviewing the lap-splice length calculation formulas of the current design standards and the ultra-high-strength concrete structural design recommendations, it was found that all of them were evaluated conservatively.

• The Journal of Engineering Geology
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• v.30 no.4
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• pp.603-615
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• 2020

The design factors of artificial recharge are determined by considering the hydrogeological characteristics of the aquifer. The optimal design factors for artificial recharge were derived after performing the injection tests step by step for each injection type (vertical well, ditch and mixed type), which were built in the test site of the study area. It was analyzed that the difference in the injection effect according to the diameter of the injection well was not large, and the 100 mm well was evaluated as appropriate in consideration of the availability and economy of land use. Since the injection effect was well maintained even in the upper rock, the depth of the injection well was proposed for the alluvial layer and the upper rock layer. On the other hand, in four cases of filter media in the ditch, it was analyzed that the penetration efficiency and the hydraulic interference effect indicated excellent injection performance when a filter medium of 10 to 30 mm diameter was filled in the ditch. In addition, the proper spacing of the injection wells was analyzed as 9~12 m considering the interference efficiency. The interference efficiency attenuation coefficient per 1 m of hole spacing was calculated to be 1.75% in this area. In the future study, the artificial recharge design factors obtained in this stage are applied and verified on site construction and operation. Also it is expected to contribute to securing water in areas where there is always a lack of water.

• Journal of Korea Water Resources Association
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• v.54 no.6
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• pp.419-431
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• 2021

In Seoul, it has been confirmed that the duration of rainfall is shortened and the frequency and intensity of heavy rains are increasing with a changing climate. In addition, due to high population density and urbanization in most areas, floods frequently occur in flood-prone areas for the increase in impermeable areas. Furthermore, the Seoul City is pursuing various projects such as structural and non-structural measures to resolve flood-prone areas. A disaster prevention performance target was set in consideration of the climate change impact of future precipitation, and this study conducted to reduce the overall flood damage in Seoul for the long-term. In this study, 29 GCMs with RCP4.5 and RCP8.5 scenarios were used for spatial and temporal disaggregation, and we also considered for 3 research periods, which is short-term (2006-2040, P1), mid-term (2041-2070, P2), and long-term (2071-2100, P3), respectively. For spatial downscaling, daily data of GCM was processed through Quantile Mapping based on the rainfall of the Seoul station managed by the Korea Meteorological Administration and for temporal downscaling, daily data were downscaled to hourly data through k-nearest neighbor resampling and nonparametric temporal detailing techniques using genetic algorithms. Through temporal downscaling, 100 detailed scenarios were calculated for each GCM scenario, and the IDF curve was calculated based on a total of 2,900 detailed scenarios, and by averaging this, the change in the future extreme rainfall was calculated. As a result, it was confirmed that the probability of rainfall for a duration of 100 years and a duration of 1 hour increased by 8 to 16% in the RCP4.5 scenario, and increased by 7 to 26% in the RCP8.5 scenario. Based on the results of this study, the amount of rainfall designed to prepare for future climate change in Seoul was estimated and if can be used to establish purpose-wise water related disaster prevention policies.

• Journal of the Korean Institute of Gas
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• v.22 no.3
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• pp.74-83
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• 2018

Anyone who wants to install local ventilation system must obtain a permission from the Ministry of Employment and Labor even if he has permission from the Ministry of Environment. This is because not only the Atmospheric Environmental Protection Act, but also the manufacturing industry's hazardous risk prevention plan under Article 48 Clause 2 of the Industrial Safety and Health Act is to be submitted by 15 days before the construction. Under the current Environmental Protection Act, the Ministry of Environment regulates only the emission of pollutants from local exhaust ventilation systems into the atmosphere and the contents of workers' safety and health within industrial sites are managed by the Ministry of Employment and Labor. Even with the approval of the Ministry of Environment, the number of unsuccessful cases by the Ministry of Employment and Labor has increased, causing a growing discontent among the sites due to production delays and additional costs of improvement. In addition, local exhaust systems that are at greater risk of fire explosion have increased the risk of severe industrial accidents due to fire explosion. This is due to insufficient design of air volume, control speed, return speed, duct size, and risk of fire explosion. This is because the criteria and procedures for approval of local exhaust ventilation systems are similar, but the Industrial Safety and Health Act adds additional screening items for safety and safety of workers and fire and explosion. In this study, the Environment Ministry and the Employment and Labor Ministry seek to find a reasonable way to operate the system by comparing local exhaust ventilation system installation approval standards.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.7
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• pp.4626-4633
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• 2014

The research is being conducted on a SFT (Submerged Floating Tunnel), because of increased exchange among nations and abnormal weather-disasters and new transportation infrastructure has attracted interest. However, studies in this are almost in the early stages around the world and various researches will be needed to promote the safety form the disaster. In this paper, heat transfer analysis was applied among the structural performance evaluation of a SFT if afire occurs in the tunnel. The analysis model of the SFT was performed as steel composite RC hollow. The impact of heat by fire under a range of fire scenarios was analyzed and prevention techniques were examined.

• Fire Science and Engineering
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• v.26 no.6
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• pp.38-44
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• 2012

The purpose of fire protection for the nuclear power plants (NPPs) is to ensure safe shutdown state of the reactor, to minimize the release of radioactive materials to the environment, to provide physical safety of the on-site personnel, and to limit the property damage. Fire protection and extinguishing equipments are one of the important protection measures based on the defense-in-depth concept, which can promptly detect and control and extinguish those fires that do occur, thereby limiting fire damage. However, a separate evaluation process might be additionally necessary for the construction permit and operating license because the fire protection laws of the NEMA for installation standards of the fire protection systems is not fully characterized for the NPPs. It is also not easy to implement the regulations such as the performance based design concept for fire protection system of the NPPs which are characterized for a relatively low density of employee. This study suggests a guideline for the improvement of the technical standards for fire protection systems of the NPPs by evaluating the fundamental problems drawn by reviewing laws and regulatory guides relevant to fire protection and by evaluating the applicability of the KEPIC FPN in domestic nuclear power plants.

• Fire Science and Engineering
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• v.26 no.6
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• pp.85-91
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• 2012

To reduce human life and property damage at the fire in a building, it is most critical to control flame spread in the early stage. Fire spread prevention measure generally includes fire resistance performance securing of structure member in the arson zone and use limitation based on combustion performance of finishing material. The latter is most fundamental fire safety design to determine flame spread, but domestic combustion test determines combustion performance by specimen sized fire test method. Thus, there are many restrictions in the determination of combustion performance by composite material such as sandwich panel. Especially, outer finishing material uses a variety of composite material such as dry bit, aluminum composite panel, and metal panel compared to inner finishing material. Therefore, this study would determine vertical fire spread features by a full scaled fire experiment through the test method of ISO 13785-2, an international test standard.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.5 s.347
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• pp.51-58
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• 2006

A variety of systems have been attempted for effective urban management. In this paper we introduce the Integrated Urban Management System (IUMS), which consists mainly of an optical line terminal (OLT), optical network terminals (ONTs) and wireless access points (APs), by combining passive optical network (PON) and radio over fiber (RoF) technologies so as to take advantage of both systems. Further, several IUMS services such as a disaster detection and prevention system (DDPS), a bus information system (BIS) and a real time location system (RTLS) we demonstrated in order to verify the employment of IUMS for the realization of a future ubiquitous city (U-city).

• Journal of the Korean Geosynthetics Society
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• v.18 no.4
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• pp.287-297
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• 2019

In this study, a series of finite element numerical analyzes were performed considering the pavement thickness and traffic load for the purpose of stability analysis on the cavity ground. In order to verify the validity of this numerical method, the previous numerical analysis was used to simulate the mechanical behavior of cavity ground, and the results were compared and analyzed. Also, from the numerical results, it was possible to confirm the dynamic behavior of the ground by confirming the change of ground void ratio, surface settlement, and shear stress, and using the relationship between stress ratio, non-destructive depth and surface settlement, the safety of the was analyzed. As a result, as the pavement thickness decreased and the traffic load increased, the non-destructive depth and the overall stability of the ground decreased with the increase of surface settlement.