• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.8
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• pp.1470-1477
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• 2008

In this paper, a new detection method of series arc-fault signals occurring at the wiring of home appliances is proposed. The discrete wavelet transform was used for the numerical analysis of the variation rate in peak, RMS, noise energy, shoulder of the arc-fault current wave. As a results, the arc distinction threshold value of these variation rates was about 0.1 in most cases. The arc-fault current of the loads with the active PFC circuit showed a high rate of variation in noise energy and shoulder, but arc-fault current of the loads without the active PFC circuit showed a high rate of variation in peak and RMS. The arc fault current in resistive loads showed a high rate of variation in shoulder.

• Steel and Composite Structures
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• v.8 no.6
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• pp.491-510
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• 2008

This paper presents a plan and guidelines that were drawn for Korean based research carried out on the fire-resistance of CFT columns. This research was carried out by reviewing the Korean regulations related to the fire-resistance of CFT columns and examining studies which had been made in Korea as well as overseas. The first phase of the study plan was to compare the fire-resistance of square CFT columns without fire protection (obtained through fire-resistance tests and numerical analyses) with estimated values (obtained through fire-resistance design formulas proposed in Korea and overseas). This comparison provided conclusions as outlined below. Fire-resistance tests conducted in this study proved that, when the actual design load is taken into consideration, square CFT columns without fire protection are able to resist a fire for more than one hour. A comparison was made of test and analysis results with the fire-resistance time based on the AIJ code, the AISC design formula and the estimation formula suggested for Korea. The results of this comparison showed that the test and analysis results for specimens SAH1, SAH2-1, SAH2-2 and SAH3 were almost identical with the AIJ code, the AISC design formula and estimation formula. For specimens SAH4 and SAH5, the estimation formula was more conservative than the AIJ code and the AISC design formula. It was necessary to identify the factors that have an influence on the fire-resistance of CFT columns without fire protection and to draw fire-resistance design formulas for these columns. To achieve this, it is proposed that numerical analyses and tests be conducted in order to evaluate the fire-resistance of circular CFT columns, the influence of eccentricity existing as an additional factor and the influence of the slenderness ratio of the columns. It is also suggested that the overall behavior of CFT structures without fire protection within a fire be evaluated through analysis simulation.

• Fire Science and Engineering
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• v.29 no.4
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• pp.7-14
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• 2015

This study suggests basic data for fire-resistant compartments to prevent fires from spreading in a traditional markets. As representative combustible goods handled in traditional markets, bedding and bags were chosen. The fire loads could be calculated using the porosity of the materials based on a standard normal distribution. The bedding and bag porosity were 98.7%, and 94.39%, respectively. The the fire load of bedding is $29.9kg/m^2$, and that of bags is $65.61kg/m^2$.

• Structural Engineering and Mechanics
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• v.74 no.4
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• pp.481-494
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• 2020

In this paper, a probability-based procedure to evaluate the performance of existing RC structures exposed to seismic and fire actions is presented. The procedure is demonstrated with reference to an existing old school building, located in Italy. The vulnerability assessment of the building highlights deficiencies under both static and seismic loads. Retrofit operations are designed to achieve the seismic safety. The idea of the work consists in assessing the performance of the existing and retrofitted building in terms of both the seismic and fire resistance. The seismic retrofit and fire resistance upgrading follow different paths, depending on the specific configuration of the building. A good seismic retrofit does not entail an improving of the fire resistance and vice versa. The goal of the current work is to study the variation of response due to the uncertainties considered in records/fire curves selection and to carry out the assessment of the studied RC structure by obtaining fragility curves under the effect of different records/temperature. The results show the fragility curves before and after retrofit operations and both in terms of seismic performance and fire resistance performance, measuring the percent improving for the different limit states.

• Computers and Concrete
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• v.19 no.5
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• pp.545-553
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• 2017

In the authors' previous study, an axial force-flexural moment (P-M) interaction curve model was proposed to evaluate fire-resisting performances of reinforced concrete (RC) column members. The proposed method appeared to properly consider the axial and flexural strength degradations including the secondary moment effects in RC columns due to fire damage. However, the detailed P-M interaction curve model proposed in the authors' previous study requires somewhat complex computational procedures and iterative calculations, which makes it difficult to be used for practical design in its current form. Thus, the aim of this study was to develop a simplified P-M interaction curve model of RC columns exposed to fire considering the effects of fire damage on the material performances and magnitudes of secondary moments. The simplified P-M interaction model proposed in this study was verified using 66 column fire test results collected from literature, and the verification results showed that the proposed simplified method can provide an adequate analysis accuracy of the failure loads and fire-resisting times of the RC column specimens.

• Journal of the Korean housing association
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• v.17 no.2
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• pp.135-142
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• 2006

The purpose of this study is to obtain the fire safety for underground commercial space with analysing fire loads and ventilation factors. It was adopted the investigation method of field survey with commercial uses for more confidential data. The results of this study can be summarized as follows; 1) The ventilation factor shows $0.04{\sim}0.24m^{1/2}$ and it may develop ventilation-controlled fires which have much fire hazard more than fuel-controlled fires. 2) The highest value of fire load is $158.48kg/m^2$ and appeared in footwear shop which has the value $137.35kg/m^2$ for unfixed combustibles and $21.13kg/m^2$ for fixed combustibles. 3) The average value of burning rates which mean the velocity of fire development and the fire damage range is 0.143. Therefore it is desired to decrease the combustibles of compartment and is needed the method of dispersion arrangement of goods and storage to steel cabinet and so on.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.45-46
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• 2018

The fire at the pilotis parking lot shows the fire propagation paths that are propagated to the ceiling materials and insulation materials and propagated through the external walls. In addition, there is a high risk of fire caused by vehicles with high combustion loads spreading throughout the parking lot. In particular, the omission of the ceiling materials at the parking lot in recent fire cases has contributed to the spread of the fire. In this study, the combustion performance of the ceiling materials between the insulation material and the vehicle is considered to prevent fire from spreading. Based on field research, the type of ceiling material used in the piloti structure showed that SMC ceiling materials have the highest percentage. Combustion performance test (KS F ISO 5660-1) was carried out on the SMC ceiling materials and the AL ceiling materials to review the fire safety of the ceiling finish based on the field investigation. The results of the test showed that the SMC ceiling materials has a THR 28.973[MJ/㎡] and peek HRR 273.93 [kW/㎡], while the AL ceiling material has a THR 0.584[MJ/㎡] and peek HRR 15.215[kW/㎡].

• Journal of the Society of Disaster Information
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• v.19 no.4
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• pp.958-967
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• 2023

Purpose: This study aims to analyze the fire resistance performance applied to plant facilities with high fire risk in Korea, secure suitable fire resistance performance, and ensure the fire safety of plant facilities. Method: Using the finite element analysis program Ansys, thermal transfer analysis and structural analysis were performed with fire load and fireproof coating as variables, and the fire resistance performance of plant facilities was analyzed based on the analysis results. Result: The fireproof coating applied to domestic plant facilities failed to secure fire resistance performance when the fire load of hydrocarbon fire presented in UL 1709 was applied, and it was confirmed that the deformation of steel after the fire was also significant. Conclusion: The current fire resistance performance applied to plant facilities in Korea cannot secure fire resistance performance in sudden fire growth and large fire loads like petrochemical plants, and it is necessary to secure fire safety by evaluating suitable fire resistance performance through performance evaluation of plant facilities.

• Steel and Composite Structures
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• v.15 no.1
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• pp.103-130
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• 2013

Fire performance and fire safety of high-rise buildings have become major concerns after the disasters of World Trade Center in the U.S. in 2001 and Windsor tower in Spain in 2005. Performance based design (PBD) approaches have been considered as a better method for fire resistance design of structures because it is capable of incorporating test results of most recent fire resistance technologies. However, there is a difficulty to evaluate fireproof performance of large structures, which have multiple structural members such as columns, slabs, and walls. The difficulty is mainly due to the limitation in the testing equipment, such as size of furnace that can be used to carry out fire tests with existing criteria like ISO 834, BS 476, and KS F 2257. In the present research, a large scale calorie meter (10 MW) was used to conduct three full scale fire tests on medical modular blocks. Average fire load of 13.99 $kg/m^2$ was used in the first test. In the second test, the weighting coefficient of 3.5 (the fire load of 50 $kg/m^2$) was used to simulate the worst fire scenario. The flashover of the medical modular block occurred at 62 minutes in the first test and 12 minutes in the second test. The heat resistance capacity of the external wall, the temperatures and deformations of the structural members satisfied the requirements of fire resistance performance of 90 minutes burning period. The total heat loads and the heat values for each test are calculated by theoretical equations. The duration of burning was predicted. The predicted results were compared with the test results, and they agree quite well.

• Advances in concrete construction
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• v.6 no.5
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• pp.485-507
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• 2018

Concrete-Filled Steel Tube (CFST) columns are an increasingly popular means to support great compressive loads in buildings. The residual strength capacity of CFST stub columns may be utilized to assess the potential damage caused by fire and calculate the structural fire protection for least post-fire repair. Ten specimens under room conditions and 10 specimens under fire exposure to the Eurocode smouldering slow-growth fire were tested to examine the effects of diameter to thickness D/t ratio and reinforcing bars on residual strength capacity, ductility and stiffness of CFST stub columns. On the other hand, in sixteen among the twenty specimens, three or six reinforcing bars were welded inside the steel tube. The longitudinal strains in the steel tube and load-displacement relationships were recorded throughout the subsequent compressive tests. Corresponding values of residual strength capacity calculated using AISC 360-10 and EC4 standards are presented for comparison purposes with the experimental results of this study. The test results showed that after exposure to $750^{\circ}C$, the residual strength capacity increased for all specimens, while the ductility and stiffness were slightly decreased. The comparison results showed that the predicted residual strength using EC4 were close to those obtained experimentally in this research.