• Journal of the Korean Institute of Gas
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• v.27 no.4
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• pp.19-26
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• 2023

Earthquakes are one of the most important disasters affecting underground structures. Urban gas underground pipes may cause safety problems of structures in the event of an earthquake. Since Korea began digital observation, the number of earthquakes has been steadily increasing. The seismic design standard for urban gas pipes was established in 2008, but it is difficult to estimate the impact of pipes in the event of an earthquake based on the installation of pipes. In this study, structural analysis was performed on PE (polyethylene pipe) pipes and PLP (polyethylene coated steel pipe) pipes, which are mainly used as buried pipes in Korea, according to environmental and pipe variables in the event of an earthquake. This study sought to find the variables of the most vulnerable buried pipe by modeling pipes through Computer Aided Engineering (CAE) and generating displacement on the ground. Through this study, it was confirmed that the larger the elastic modulus of the soil, the deeper the buried depth, the smaller the tube diameter, and the higher the pressure, the more PLP pipes are affected by earthquakes than PE. Based on these results, the vulnerable points of buried urban gas pipes are inferred and used for special inspections of buried pipes in the event of an earthquake.

• Journal of Bio-Environment Control
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• v.16 no.4
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• pp.297-302
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• 2007

Discharge variations of perforated hose and drip irrigation systems were examined to evaluate irrigation uniformity at different pressures and length of branch line. Evaluation using statistical uniformity indicated that button drippers performed at excellent level but drip tapes and drip hoses were a little lower level. Nominal discharge of drip irrigation systems showed at the high side within the range of regulating pressure provided by the manufacturer. It is desirable that the length of branch line for drip hose, drip tape, and button dripper should be limited to 50 m, 70 m, and 100 m, respectively. Irrigation uniformity of perforated hoses showed very low level. So it is recommended that the length of branch line for perforated hoses should be limited to $30{\sim}35m$.

• Journal of the Korean Society for Nondestructive Testing
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• v.36 no.6
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• pp.496-503
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• 2016

Leakages at plant structures of power and petrochemistry plants have led to casualties and economic losses. These leakages are caused by fatigue failure of pipelines and their wall thickness. Vibration measurement methods for plant pipelines mainly use acceleration and laser sensors. These sensors are difficult to install and operate and thus lead to an increase in operational cost especially for wide area surveillance. Recently, measurements of leak and vibration displacements using cameras have attracted the interest of many researchers. This method has advantages such as simple installation, long distance monitoring, and wide area surveillance. Therefore, in this paper, we have developed a system that can measure the leakage and vibrational displacement by using a camera. Furthermore, the developed system was verified with experimental data.

• Special Issue of the Society of Naval Architects of Korea
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• 2005.06a
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• pp.127-133
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• 2005

DSME has successfully developed the unified CAD system (DACOS) for the commercial ship based on its design know-how accumulated for several years. Currently, DSME is expanding the unified CAD system to plant and special ship design. In this paper, the development of pipe design, especially, isometric drawing and BOM(Bill of Material) generation will be introduced isometric drawing and BOM generation are major activities of pipe design in shipbuilding. The drawing is used for pipe construction and installation while the BOM is used for purchasing and manufacturing pipe line. These activities are time-consuming and tedious jobs done by designers because the drawing should be generated as a non-scaled symbolized drawing that can be easily understood and the BOM information should be extracted without mistake. Therefore, we implemented automatic isometric drawing and 80M generation system for pipe design. In this paper, the developed system and the used technology will as well be introduced and a design output in a plant project as an applied example will be illustrated.

• Journal of the Korean Institute of Gas
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• v.14 no.4
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• pp.18-23
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• 2010

After conducting QRA(quantitative risk assessment) for the high pressure urban gas pipelines planned to be installed, RMMs(risk mitigation measures) when the societal risk is outside the acceptable region have been derived in this paper. Also risk reduction rates are calculated for each RMM. As a result of QRA, we find out that damaged distance caused by radiational heat is largely dependent upon the wind velocity and the atmospheric stability. The measure that has the highest risk reduction effect is No. 10 which includes pipeline corrosion monitoring, MOV(motor operated valve) installation and the method to protect pipeline damage caused by third-party mechanical interference, and which shows 75 % of risk reduction effect.

• Korean Chemical Engineering Research
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• v.57 no.2
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• pp.225-231
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• 2019

In Korea, the minimum separation distance between aboveground high-pressure natural gas pipeline and buildings is regulated by Korea gas safety (KGS) code. In this paper, The technical backgrounds for the revision of the KGS code related to the minimum separation distance was presented. A consequence-based approach was adopted to determine the minimum separation distance by a reasonable accident scenario, which was a jet fire caused by the rupture of one inch branch line attached the gas pipeline. Where, the higher thermal radiation flux threshold was selected for workers in industrial area than for people in non-industrial area, because the workers in industrial area were able to escape in a shorter time than the people in public. As result of consequence analysis for the accident scenario, we suggested the KGS code revision that the minimum separation distances between high-pressure natural gas pipeline installed above ground and buildings should be 30 meter in non-industrial area and 15 meter in industrial area. The revised code was accepted by the committee of the KGS code and now in effect.

• Journal of the Korean Institute of Gas
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• v.23 no.3
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• pp.20-26
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• 2019

Selective catalytic reduction(SCR) method is widely used among various methods for reducing nitrogen oxides in combustion devices of coal power plant. In the present study, the computational fluid dynamic analysis was accomplished to derive the optimal shape of ammonia-dilution air mixing device in a ammonia injection grid. The distribution characteristics of flow and $NH_3$ concentration had been elucidated for the reference shape of ammonia mixing device(Case 1). In the mixing device of Case 1, it could be seen that $NH_3$ distribution was shifted to the wall opposite to the inlet of the ammonia injection pipe. For the improvement of $NH_3$ distribution, the case(Case 2) with closing one upper injection hole and 4 side injection holes, the case(Case 3) with installing horizontal plate at the upper of ammonia injection pipe, the case(Case 4) with installing horizontal plate and horizontal arc plate at he upper of ammonia injection pipe were investigated by analyzing flow and $NH_3$ concentration distributions. From the present study, it was found that the % RMS of $NH_3$ for Case 4 was 4.92%, which was the smallest value among four cases, and the range of $R_{NH3}$ also has the optimally uniform distribution, -10.82~8.34%.

• 월간 기계설비
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• no.1 s.186
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• pp.54-55
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• 2006

한국건설기술연구원은 지난 해 12월 30일 2006년 1월 1일부터 적용되는 46개 항목의 건설공사 표준품셈을 관계기관 실무자로 구성된‘품셈 위원회’의 심의를 거쳐 최종 확정, 공표했다. 건기연은 신기술의 적용성을 높이기 위해 실제 사용되는 공법을 중심으로 기계설비부문에서는 발열선등 5개의 품셈이 신설되었고, 기존 품셈의 조문정리 등 체계보완이나 적정성 조정을 위해 재료 할증률등 4개 항목을 보완했다. 기계설비부문의 발열선 품은 배관 동파방지를 이해 가구내 급수 급탕 계량기 주위, 가스보일러 하부배관 및 옥외지하주차장 배관 등에 발열선을 설치하고 있으나 적정품이 없어 전기표준품셈의 Heat Tracing System을 준용하고 있어 가구내와 공용부위로 구분해 신설한 품이다. 건기연은 품셈개정을 위해 지난해 3월 각 발주기관과 관련단체의 의견을 수렴해 대상항목을 선정한 데 이어 지난해 10월까지 건설현장에 대한 실사를 통해 수집한 자료를 토대로 품셈을 신설∙보완했다고 밝혔다.

• Fire Science and Engineering
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• v.29 no.3
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• pp.21-30
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• 2015

In this study, we try to suggest measures to reduce leakage at a joint between CPVC piping for a sprinkler system and a pipe expansion through reviews of domestic and foreign standards and related tests. The quality of the waterproof rubber packing material between a valve socket and pipe expansion nut was examined. In the leak test, the valve socket material over the expansion part of the metal pipe nut was found to use a metal part or a schlorinated polyvinyl chloride pipe nut part. In addition, the KS B 0221 standard for parallel pipe threads with threaded and thread inspection criteria and inspection standards in order to ensure an acceptable quality of valve socket, there is a need to amend the regulations to comply with the KS B 5223 (screw thread limit gauges parallel pipe threads). We do not have detailed standards for expansion piping nuts for waterproof rubber ring material, so we need to amend the relevant criteria for EPDM material to be used with excellent waterproofing, for which both NBR and EPDM are currently used.

• Journal of Industrial Convergence
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• v.18 no.4
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• pp.15-21
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• 2020

Because there are no isolation valves in condensate system of nuclear power plants, circulating water pump was shutdown for the condenser repair. When circulating water pump was shutdown, power plant output decreased about 45%. These output decreasing can minimize by establishing isolation valves. In this paper, evaluated effect to flow conditions change of condensate system, structural integrity of system, condenser pressure of in case of establish isolation valves to condensate system. Results of the evaluation, the flow rate due to the installation of the isolation valve decreased 0.3% when the valve was fully opened and 4.5% when fully closed. In addition, it was found that the vacuum degree of the condenser decreased with decreasing flow rate, but the integrity of the system was maintained.