• Journal of the Korea Institute of Building Construction
• /
• v.9 no.4
• /
• pp.63-73
• /
• 2009

Recently, the use of lightweight panels in building structures has been increasing. Of the various lightweight panel types, styrofoam sandwich panels are inexpensive and are excellent in terms of their insulation capacity and their constructability. However, sandwich panels that include organic material are quite vulnerable to fire, and thus can numerous casualties in the event of a fire due to the lack of time to vacate and their emission of poisonous gas. On the other hand, lightweight foamed concrete is excellent, both in terms of its insulation ability and its fire resistance, due to its Inner pores. The properties of lightweight concrete is influenced by foaming agent type. Accordingly, this study investigates the insulation properties by foaming agent type, to evaluate the possibility of using light-weight foamed concrete instead of styrene foam. Our research found thatnon-heating zone temperature of lightweight foamed concrete using AP (Aluminum Powder) and FP (animal protein foaming agent) are lower than that of light-weight foamed concrete using AES (alkyl ether lactic acid ester). Lightweight foamed concrete using AES and FP satisfied fire performance requirements of two hours at a foam ratio 50, 100. Lightweight foamed concrete using AP satisfied fire performance requirements of two hours at AP ratio 0.1, 0.15. The insulation properties were better in closed pore foamed concrete by made AP, FP than with open pore foamed concrete made using AES.

• The Journal of the Acoustical Society of Korea
• /
• v.41 no.3
• /
• pp.302-311
• /
• 2022

Sound barrier walls are one of the most effective alternatives for reducing environmental noise on roads and railways in the city center. The insertion loss of the sound barrier against road traffic noise is the sum of the sound transmission loss, sound absorption loss, and sound energy reduction due to the diffraction attenuation of the sound barrier. The sound transmission loss of the sound barrier is one of the important factors that determine the insertion loss of the sound barrier and is a basic indicator that determines the performance of the sound barrier. Nevertheless, there is not a separate standard in Korea for measuring the acoustic transmission loss of sound barrier panels. There are only a few conditions in KS F 4770 series that stipulates on the general material of sound barrier panels. This thesis examines the necessity of the acoustic transmission loss measurement and evaluation standards of sound barrier walls, and seeks a measurement method in a free sound field (anechoic chamber) sound receiving room considering the characteristics of sound barrier walls installed in external spaces, unlike indoor building materials. In addition, a single number evaluation method using a reference spectrum was proposed so that the sound insulation effect according to various installation places such as roadside or railroad side can be easily displayed.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.3
• /
• pp.1585-1593
• /
• 2015

3D-structured (embossed) aluminum sheets have been used in the heat insulation purpose for automative exhaust parts because of increasing their surface areas and stiffness reinforcement imposed in making the embossing pattern. However, there are many restrictions in press forming of the embossed sheet compared with the flat sheet (non-embossed one) because of its difference in the mechanical properties and the geometrical 3-dimensional shape. In this paper we investigated the deformation characteristic of embossed aluminum sheet in the incremental sheet forming process which has frequently used in the design verification and the trial manufacturing of sheet products. The single point incremental forming (SPIF) experiments for the rectangular cone forming using the CNC machine with a chemical wood-machined die and a circular tool shape showed that the formability of the embossed sheet are better than that of the flat sheet in view of the maximum angle of cone forming. This comes from the fact that the embossed sheet between the tool and the elastic die wall is plastically compressed and the flatted area contributes to increase the plastic deformation. Also the tool path along the outward movement from the center showed a better formability than that of the inward movement from the edge. However the surface quality for the tool path along the outward movement evaluated from the surface deflection is inferior than that of the tool path along the inward movement.

• Fire Science and Engineering
• /
• v.24 no.6
• /
• pp.7-12
• /
• 2010

This paper is aimed the measurement and estimation the thermal interrelation based on leakage current. The leakage models are analyzed by parameters in open and closed (Panel) states and with wood dust and rainwater, charcoal powder in leakage current occurred point. The thermal characteristic of open state that leakage current is inputted in 90 mA is higher in charcoal powder ($105^{\circ}C$) than in wood dust and rainwater ($88.8^{\circ}C$). Charcoal powder that is inputted in 110 mA shows high thermal characteristic ($238.6^{\circ}C$) and the thermal ($238.6^{\circ}C$) is caused by material strain of electrical wire insulation and Panel. The closed state in 90 mA is higher in charcoal powder ($250.6^{\circ}C$) than in wood dust and rainwater ($90.8^{\circ}C$). The open and closed state appear thermal characteristics of two times in charcoal powder than in wood dust and rainwater. The thermal data that are open and close states are used electrical fire investigation and thermal characteristic for Leakage current.

• Journal of Korean Society of Steel Construction
• /
• v.18 no.5
• /
• pp.543-551
• /
• 2006

Cold-formed steel studs that are being used as load-bearing members of wall panels for steel houses have a problem with their insulation due to the heat bridging of their web. Some additional thermal insulating materials should be used. To solve this problem, the new-concept hybrid stud, which consists of a galvanized steel sheet (t = 1.0 m - 12.0 m) and a GFRP panel (t = 4.0-6.0 mm), has recently been developed. An investigation on the structural behavior and the strength capacity of this new hybrid stud has been conducted so that it can be used in load-bearing wall panels of residential buildings. This paper describes the axial compression-torsion test results of the hybrid studs under both axial compression and torsion using ATTM. The main factors of the test were the stud length, the magnitude of the initial compressive force, and the loading method of the monotonic or cyclic loading. The torsion was applied increasingly while the initial compression was kept constant to the failure of the hybrid section. The advanced analysis results obtained form the finite element procedure that considered the material properties of the high-strength galvanized steel and the GFRP were compared with the test results for verification.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.28 no.10
• /
• pp.387-393
• /
• 2016

A ground source heat pump system maintains a constant efficiency due to its stable heat source and radiant heat temperature which provide a more effective thermal performance than that of the air source heat pump system. As an eco-friendly renewable energy source, it can reduce electric power and carbon dioxide. In this study, we analyzed one year of data from a web based remote monitoring system to estimate the thermal performance of GSHP with the capacity of 3RT, which is installed in a low energy house located in Daejeon, Korea. This GSHP system is a hybrid system connected to a solar hot water system. Cold and hot water stored in a buffer tank is supplied to six ceiling cassette type fan coil units and a floor panel heating system installed in each room. The results are as follows. First, the GSHP system was operated for ten minutes intermittently in summer in order to decrease the heat load caused by super-insulation. Second, the energy consumption in winter where the system was operated throughout the entire day was 7.5 times higher than that in summer. Moreover, the annual COP of the heating and cooling system was 4.1 in summer and 4.2 in winter, showing little difference. Third, the outlet temperature of the ground heat exchanger in winter decreased from $13^{\circ}C$ in November to $9^{\circ}C$ in February, while that in summer increased from $14^{\circ}C$ to $17^{\circ}C$ showing that the temperature change in winter is greater than that in summer.

• Solar Energy
• /
• v.10 no.2
• /
• pp.18-27
• /
• 1990

The hot water producer by the combination of the solar thermal energy and freon gas compression heat has been developed. Freon R-12 gas was circulated through the system including the solar absorption panel, which has no glassing and no insulation, and the frozen and burst problems were intrinsically eliminated. The manufacturing and running costs may go further down than the regular solar hot water systems.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.2
• /
• pp.921-926
• /
• 2015

Embossed aluminum sheets were been used in heat insulation purpose for automative exhaust parts because of increasing their surface areas and stiffness reinforcement. However, there are many restrictions because of high rate of wrinkle occurrence on press working. We have performed the tensile and bending tests for embossed sheets to clarity its mechanical properties and springback characteristics. Embossed aluminum sheets showed a different flow stress after plastic yielding due to flattening the embossed cone shape. Above all, yield stress of parallel embossed specimen decreases while its diagonal one increases and the decrease of young's modulus in the embossed sheets contributes to the increase of springback amount.

• Fire Science and Engineering
• /
• v.20 no.4 s.64
• /
• pp.33-41
• /
• 2006

Nowadays in Korea, KS F 2271(Testing method for incombustibility of internal finish material and element of buildings) has been using for the evaluation of fire safety performance of sandwich panels. The test method in Japan and in Korea was based on the same way. When the Japanese standard building code was revised in 2000, the test method in the ISO 5660-1 was adopted for the test method for combustion performance of internal finishing materials and elements of buildings. According to this, the revision version of draft substituting the test method in the KS F 2271 for one in the ISO 5660-1(Cone Calorimeter method) is informed in Korea. In this study, combustion properties of sandwich panels were tested using the cone calorimeter method. Ignition time, peak heat release rate and total heat released of four sandwich panels and four core materials (thermal insulation material), which are widely used in Korea, were tested. Test results were analyzed for each specimen. Finally, test results were classified by Japanese standard building code and Canadian NBC revised.

• Industry Promotion Research
• /
• v.4 no.2
• /
• pp.1-8
• /
• 2019

This research is a technology for cutting the insulation of the busbar (busbar) installed in the distribution panel or switchboard, the results of the study, first, the cutting unit and frame of the cutting unit including a housing attached to the upper and lower cutters, respectively Busbar coating laser cutting machine is installed on the top, characterized by consisting of a stopper for adjusting the coating cutting distance of the busbar. Second, the frame is installed with the guide bar in the longitudinal direction at the top so as to be located at the rear side end of the table, the post is installed vertically at the front and rear at the upper middle part, respectively, and cut to the table at the outer side of the front post. It is characterized by the formation of holes. Third, the supporter is fixedly installed on the upper part of the guide bar arranged in the frame, and is characterized by consisting of a cylinder and a support plate. The meaning of this study is to prevent the safety accidents of workers, to improve the efficiency of cutting work, and to prevent the occurrence of scratches on the surface of the busbar.