• Fire Science and Engineering
• /
• v.33 no.2
• /
• pp.9-19
• /
• 2019

Experiments on the combustion characteristics of untreated wood specimens and those treated with four types of silicone compounds were carried out using a cone calorimeter according to the ISO 5660-1 standard. 3-Aminopropyltrimethoxysilane (APTMS), 3-(2-aminoethylamino) propylmethyldimethoxysilane (AEAPMDMS), and 3-(2-aminoethylamino) propyltrimethoxysilane (AEAPTMS) were used as the silane compounds. The flame retardants were synthesized with sodium silicate and amino silane compounds. The measured time to ignition after combustion at an external heat flux of $50kW/m^2$ was 9 s to 11 s. Time to ignition was marked with a delayed value in the 3 s to 5 s range. The peak heat release rate ($HRR_{peak}$) was reduced by 5 to 20% compared with the uncoated specimen, and AEAPMDMS showed the highest initial fire risk. The total heat release (THR) was decreased by 1 to 22%. Compared to the untreated specimen, the fire performance index (FPI) of the specimens coated with silicone sol compounds increased by 1.5 to 2.2 fold. The fire growth index (FGI) of the AEAPMDMS specimen was increased by 30% and the others were decreased by 93 to 94%. Therefore, the fire risk of wood coated with silicone compounds was improved in terms of the heat risk properties.

• Fire Science and Engineering
• /
• v.33 no.1
• /
• pp.121-129
• /
• 2019

In Korea, life safety assessment through simulation are mandatory in performance-based design. Generally, there are three types of methods for simulation-based life safety assessments: the non-coupling method that compares available safe egress time (ASET) and required safe egress time (RSET) at a specific point through conducting fire and assessment simulations independently; the semi-coupling method that compares fire and evacuation simulation results by overlaying the result screens; and the coupling method that compares the results of fire effect simulation to an evacuation simulation. Of these methods, all designers in South Korea have used the only non-coupling method. In the non-coupling method, it is important to determine the location of a specific point to compare ASET and RSET. However, without any defined regulation, setting the location is determined based on the designer's experience and knowledge. The number of specific locations and the locations themselves differ with each designer, which can produce contrasting results in a life safety assessment. Therefore, this study conducted a life safety assessment based on the three methods (non-coupling, semi-coupling and coupling) and compared each of the results. Furthermore this study suggests a improvement way in particular for the computer simulation.

• Fire Science and Engineering
• /
• v.33 no.1
• /
• pp.69-75
• /
• 2019

In this study, the combustibility of five types of plastic plates, fiber reinforced plastic (FRP), polystyrene (PS), polycarbonate (PC), polypropylene (PP), and polyvinyl chloride (PVC), were tested using a cone calorimeter (ISO 5660). The PVC plate showed a $44.65kW/m^2$ lower peak heat release rate (HRR) and a $30.97kW/m^2$ lower maximum average rate of heat emission than the other four types of plastics, whereas the PS plate showed a $773.44kW/m^2$ higher peak HRR and $399.14kW/m^2$ higher maximum average rate of heat emission. The PC plate and PS plate showed the highest HRR by a maximum of 3.88 times in $CO_{mean}$ yields, while the PS pate and PP plate showed the highest HRR by a maximum 4.88 times in $CO_{2mean}$ yields. In addition, the smoke performance index (SPI) of the PS plate decreased by 74.81%~95.99%; the smoke growth index (SGI) increased to 76%~300%; the smoke intensity (SI) also increased to 917.73% ~ 9607.57%, and the danger of smoke increased. The PS plate was found to have the highest risk of life damage due to smoke on the thermal and smoke sides.

• Journal of the Korean Institute of Traditional Landscape Architecture
• /
• v.37 no.1
• /
• pp.33-40
• /
• 2019

The purpose of this study is to analyze historical records of what the trees had been planted like by establishment and management of the Royal Tombs of the Joseon Dynasty so that it could be utilized for historical records to manage the trees in the Royal Tombs. The research method was to analyze the related keywords for 40 trees out of 42 trees in the Royal Tombs of the Joseon Dynasty reffering to "The Annals of the Joseon Dynasty(朝鮮王朝實錄)," and "Neungji(陵誌)". There are two types of planting called Jeongsik(定植) Bosik(補植) in the Royal Tombs. Jeongsik(定植) is a planting method by Salleungdogam(山陵都監), the office in charge of construction of the royal tomb when they were building the royal tomb. Every tree additionally planted after building up the royal tomb was called Bosik(補植). The types of tree planting the composition and management of the royal tombs of Joseon are as follows. First, the first planting for landscaping was carried out during the process of building the province. Second, after the formation of Shanung, all the plants were planted by Wangmyung as additional plants. Third, due to the deforestation in the late Joseon period, additional plants were planted in the fertile plains. Fourth, trees were damaged due to natural disasters, and trees were planted together with the construction of the botanical gardens. Fifth, in the 22nd year of King Jeongjo, all the royal families' graves were regularly planted. This study aims to investigate the history of forest landscape management for the restoration of the royal tombs of Joseon.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.31 no.5
• /
• pp.241-252
• /
• 2019

To choose appropriate countermeasures against potential coastal disaster damages caused by a storm surge, it is necessary to estimate the frequency of storm surge heights estimation. As the coastal populations size in the past was small, the tropical cyclone risk model (TCRM) was used to generate 176,689 synthetic typhoons. In simulation, historical paths and central pressures were incorporated as a probability density function. Moreover, to consider the typhoon characteristics that resurfaced or decayed after landfall on the southeast coast of China, incorporated the shift angle of the historical typhoon as a function of the probability density function and applied it as a damping parameter. Thus, the passing rate of typhoons moving from the southeast coast of China to the south coast has improved. The characteristics of the typhoon were analyzed from the historical typhoon information using correlations between the central pressure, maximum wind speed ($V_{max}$) and the maximum wind speed radius ($R_{max}$); it was then applied to synthetic typhoons. The storm surges were calculated using the ADCIRC model, considering both tidal and synthetic typhoons using automated Perl script. The storm surges caused by the probabilistic synthetic typhoons appear similar to the recorded storm surges, therefore this proposed scheme can be applied to the storm surge simulations. Based on these results, extreme values were calculated using the Generalized Extreme Value (GEV) method, and as a result, the 100-year return period storm surge was found to be satisfactory compared with the calculated empirical simulation value. The method proposed in this study can be applied to estimate the frequency of storm surges in coastal areas.

• Journal of Korean Society of Forest Science
• /
• v.109 no.4
• /
• pp.446-453
• /
• 2020

By applying the Analytic Hierarchy Process(AHP) method, we calculated the weight of factors related to the selection of check dam sites and generated basic data related to the selection of the target site. As a result of the AHP classification, three evaluation items(Susceptibility, Vulnerability, and Constructability), 12 evaluation factors (Susceptibility 10, Vulnerability, and Constructability 1), and two-six evaluation criteria in each evaluation factor were selected. After calculating the relative importance by using the selected evaluation items, evaluation factors, and criteria, the vulnerability items such as medical facilities, facilities for the aged, educational facilities, and private homes were found to be higher than the other items. When the relative weight for deciding qualified sites was applied to the forest watersheds in the Gangwon region, 8,601 forest watersheds(35.2 % of the total forest watersheds) were found to be suitable for the installation of check dams.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.23 no.4
• /
• pp.234-252
• /
• 2020

This paper is to verify the effectiveness of 'Hybrid Disaster Management Strategy' that integrates 'RTM(Real-time Monitoring) based On-line' and 'UAV based Off-line' system. For landslide prone area where sensors were installed, the conventional way of risk management so far has entirely relied on RTM data collected from the field through the instrumentation devices. But it's not enough due to the limitation of'Pin-point sensor'which tend to provide with only the localized information where sensors have stayed fixed. It lacks, therefore, the whole picture to be grasped. In this paper, utilizing 'Digital Photogrammetry Software Pix4D', the possibility of inference for the deformation of ungauged area has been reviewed. For this purpose, actual measurement data from RTM were compared with the estimated value from 3D point cloud outcome by UAV, and the consequent results has shown very accurate in terms of RMSE.

• Applied Chemistry for Engineering
• /
• v.32 no.4
• /
• pp.417-422
• /
• 2021

In this study, poly isocyanurate foam (PIR), poly urethane foam (PUR), and phenol foam (PF) of organic insulation materials were selected, and investigated using a cone calorimeter, as per ISO 5660-1. Standard materials (PMMA) were used to standardize the fire hazard assessment, and the fire risk was classified and evaluated by Chung's equations-III and IV. The fire performance index-II value of Chung's equations-II was the highest value with PF of 14.77 s²/kW. And the PUR was 0.08 s²/kW, the lowest value of fire performance index-II value. The fire growth index-II value was the lowest value with PF of 0.01 kW/s². And the PUR was 1.14 kW/s², the highest value of fire growth index-II value. The fire performance index-III (FPI-III) of Chung's equations-III had the lowest value for PUR (0.11) and the highest for PF (20.23). The PUR showed the highest value of the fire growth index-III (FGI-III) as 14.25, while the PF exhibited 0.13 regarded as the safest materials. The fire risk index-IV (FRI-IV) value of Chung's equation-IV was in the following order: PUR (130.03) >> PIR (19.13) > PMMA (1.00) > PF (0.01). Therefore, it was concluded that the fire risk associated with PF is the lowest, whereas that associated with PUR is the highest.

• Journal of Korea Water Resources Association
• /
• v.54 no.6
• /
• pp.443-452
• /
• 2021

The authors obtained the discrete hedging rule for a reservoir's water supply operation by applying mixed-integer programming to save more water by earlier rationing of water supply for a drought period. The 'water supply adjustment guide' is the current operational method applied to the multipurpose reservoirs, and it was derived by a simulation method. Applying the two rules to the Hapcheon multipurpose dam's reservoir simulations with the inflow record from 2003 to 2018, the water supply deficit occurred for the long drought from 2015 to 2018. Especially, the no water supply or intermittent water supply persisted for the second half of 2017. The water supply adjustment guide had the 'normal water supply recovery threshold on storage,' which resulted in the water supply being unavailable in July 2017; then, the water supply suspension occurred until January 2018, when the reservoir storage was greater than the normal water supply recovery threshold. Despite the storage increasing due to the inflow of water into the reservoir, the suspension occurrence needs to be improved in practice. The current water supply adjustment guide and the discrete hedging rule for a reservoir's water supply operation are useful and realistic as the reservoir operation guide, which shows the concept of reducing water supply during the drought phase as scientific figures. However, to improve the reservoir simulation results, which do not provide any or intermittent water for several months, it is necessary to increase the current water supply reduction for drought phases.

• Applied Chemistry for Engineering
• /
• v.32 no.4
• /
• pp.423-430
• /
• 2021

In order to evaluate the fire risk and fire risk rating of wood for construction materials, this study focused on fire performance index-III (FPI-III), fire growth index-III (FGI-III), and fire risk index-IV (FRI-IV) according to Chung's equations-III and -IV. Western red cedar, needle fir, ash, and maple were used as the specimens. The fire characteristics were investigated using a cone calorimeter (ISO 5660-1) equipment on the specimen. The FPI-III measured after the combustion reaction was 0.86 to 12.77 based on polymethylmethacrylate (PMMA). The FGI-III was found to be 0.63 to 5.26 based on PMMA. The fire rating according to the FRI-IV, which is the fire rating index, was 0.05 to 6.12, and the western red cedar was 122.4 times higher than that of the maple. The fire risk rating according to the FRI-IV increased in the order of maple, ash, needle fir, PMMA and western red cedar. The CO peak concentration of all specimens was measured as 103 to 162 ppm, and it was 2.1 to 3.2 times higher than 50 ppm, the permissible exposure limits of the US occupational safety and health administration. Materials such as western red cedar, which have a low bulk density and contain a large amount of volatile organic substances, have a low FPI-III and a high FGI-III, so they have a high fire risk rating.