• Journal of Korean Society of Water and Wastewater
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• v.27 no.6
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• pp.679-687
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• 2013

Although stable and safe drinking water supply to the customers is a basic function of multi-regional water supply systems in Korea, most systems have their vulnerabilities in emergency time due to the branch-type. Application of connections from the other water supply system can provide a solutions for these tentative problems. This paper describes reduction planning of water supply accidents that can minimize a service interruption to customers in multi-regional water supply system by connecting pipe lines between local water supply systems in Mokpo city areas. The result of this study shows that Juam dam multi-regional water supply systems can cover all of the water shortage in southern parts of Jeonnam multi-regional water supply systems by transmitting water through connected pipes between local networks. This can be effective to supply water interactively in various contingencies, when a pipe line accident occurs in southern area of Jeonnam multi-regional water supply systems. On the contrary, southern area of Jeonnam multi-regional water supply systems can cover 99.5 %($62,500m^3/day$) of the water shortage of Juam dam multi-regional water supply systems when service interruptions caused by various pipe accidents occur in the system.

• The Journal of Korea Robotics Society
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• v.16 no.3
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• pp.223-231
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• 2021

In this paper describes the research and development of a pipe robot for pipe rehabilitation construction of old water pipes. After the water supply pipe construction, the pipe is leaking, damaged, and aging due to corrosion. Eventually, resistance to the flow of water in lower supply efficiency and contaminated water such as rusty water, finally in various consumer complaints. In order to solve this problem, rehabilitation construction robot technology is required to secure the construction quality of pipe rehabilitation construction and restore the function of the initial construction period. The developed pipe rehabilitation construction robot required a hydraulic actuator for high traction and was equipped with a small hydraulic supply device. In addition, we have developed a hydraulic cylinder and a link system that supports the pipe inner diameter to develop a single pipe robot corresponding to 500 to 800mm pipe diameter. The analysis and experimental verification of the driving performance and unit function of the developed pipe reconstruction robot are explained, and the result of the integrated performance test of the pipe reconstruction robot at the water supply pipe network site is explained.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.4
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• pp.228-232
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• 2015

The water supply galvanized steel pipes of apartment buildings in Bucheon city constructed with building permission before 1994 have many problems such as leaks, the water containing rust, and low water pressure due to corrosion. Therefore, this study aims to find a way to renew the water supply pipes under investigation through a survey. As a result, when replacing the galvanized steel pipe with the corrosion-resistant pipe, the water supply system should also be changed from the gravity tank system to the booster pump system and the hygienic water storage tank. It is necessary to redraft the long-term repair plan including the replacement of the water supply system. Also, it is necessary to save the allowance reserve according to the modified long-term repair plan.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.11
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• pp.782-788
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• 2007

In this paper, the freezing process of the water supply pipe in the exterior wall of an apartment house was analyzed by numerical method. The thickness of the pipe insulation and the percentage of insulation damage were considered as parameters in this paper. In the cases of the 0%, 8% and 20% damaged of the 5mm thickness insulation, the freezing was completed after 13 hours, 10 hours and 7 hours respectively. And in cases of the 10mm thickness insulation, the freezing was completed after 18 hours, 10.5 hours and 8 hours respectively. As a result, it is predicted that the water freezing would occurred when the water supply pipe with 8% or 20% damaged insulation are installed in the exterior wall. However, the water freezing would not occurred when the water supply pipe with 10mm thickness insulation of 0% damage is installed in the exterior wall.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.5 no.4
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• pp.33-40
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• 2006

The quality of the supply water which is supplied to consumer is not the thing of water after filtrating but the thing of water from faucet through pipe. As a result, heavy metals and microorganism, that is the major materials, which cause the distrust of the supply water is generated by supply process. Especially, the heavy metal is generated by the corrosion of waterworks. Besides, rupture by corrosion of pipe becomes the factor of supply water's pollution in waterworks and the factor of pollution of the soil and environment in drain pipe. Therefore, this research examined the weight reduction electric potential measure to measure the corrosion degree of piping materials after testing the corrosion of piping materials(Copper Pipe, Galvanized Steel Pipe, Stainless Steel Pipe) which is generally used at the moment in various corrosion environments(subterranean water, supply water, 3.5% NaCl, 3.5% $HNO_3$). And let me show basic design data about problem occurrence such as leakage water, rust water, inside and outside corrosion from this.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.30 no.1
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• pp.44-49
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• 2018

High-strength plastic water supply pipe evaluation method was evaluated in this study. Up to date, high strength water supply pipes that we install are mostly ductile cast iron pipes. Sometimes, a few PVC pipes are installed. Metal pipes have rust problem on the surface, causing serious damage to metal pipes and reducing the expected life span of water piping system. Nowadays, depending on technology development, some companies have improved properties of general PVC pipe performance with remarkable properties that exceed KS and ASTM standard. Here, we suggest a new method of performance evaluation for high-strength water plastic pipes.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.2
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• pp.249-256
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• 2012

The paper describes a design methodology that can select a proper reliability factor and apply the selected reliability factor into the real water distribution system. Reliability factors which are used for the assesment of water supply networks, can be categorized by a connectivity, a reachability, an expected shortage and an availability. Among these factors, an expected shortage is the most proper reliability factor in the aspect of economic evaluation. Therefore, the expected shortage is applied to draw a water supply reliability into Changwon water supply systems. And the economic pipe diameter can be determined as 600mm for a connection pipe in the pipe network from the estimation of the expected shortage. Also, a quantitative effect of the connection pipe can be expressed in terms of the reduction, which is estimated by the expected shortage of 30,269$m^{3}$ from 68,705$m^{3}$ at initial condition to 38,436$m^{3}$ under the connected condition with the diameter 600mm pipe.

• Journal of Korean Society of Water and Wastewater
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• v.16 no.6
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• pp.686-699
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• 2002

The purpose of this study is to estimate deterioration factors and weighting factors in pipe network which each local self-governments takes rehabilitation and replacement work present time. Deterioration factors in pipe network are able to effected of specific province or location related with water supply. Most of water supply pipes are laid under the ground, it is hard to quantify deterioration degree of water system. Moreover, the timing and economic limitation and insufficient information on the spot survey gives a difficulty to look over how old water supply system is. Accordingly, this study collects and analyses five data as the laying environment, visual analysis, analysis of soil contents, analysis of pipe material, and questionary survey data in water pipe of A city. The deterioration factor estimates 14 factors with excavation and experimental analysis and 9 factors without excavation and experimental analysis. Also, the weighting factors are estimated by using the multiple linear regressions and the linear programming. The estimated deterioration factor and weighting results are compared the analysis result of visual, pipe material, and soil contents with the Probabilistic Neural Network Model. Consequently, the model results of estimated 9 factors in this study and 14 factors show the 1-2% difference. The result show that the proposed model could be used to decide the deterioration condition of pipe line with real excavation and experimental analysis.

• Journal of Korea Water Resources Association
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• v.43 no.7
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• pp.609-623
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• 2010

In this paper the feedback loop mechanisms that are inherent in the management of water supply systems were identified based on the system dynamics modeling methodology. As a result, a system dynamics (SD) computer simulation model that can be used to aid efficient management of water supply systems was developed. The developed SD model can be used to predict operating conditions of water supply systems including the effects of pipe maintenance on the entire system. The developed model is consisted of water supply, pipe maintenance and water supply business finance model. The operation and maintenance data from a study water supply system were used to verify the model and to predict the past and future operating conditions of the system. The policy leverage that greatly affects the operating condition was evaluated by the sensitivity analyses for the operational indices due to changes in the exogenous variables. It was found that while the pipe maintenance related exogenous variables had great effects on the leakage and conditions of pipes, they did not have great effects on the major operational indices such as revenue water ratio. It is considered that the social costs due to leaks and pipe breaks and the corresponding mechanism of propagation of the costs must be modeled to better evaluate the effects of pipe maintenance on the operational conditions of water supply systems.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.12
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• pp.733-740
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• 2017

'The facilities standards of water supply' issued by the Ministry of Environment in 2004 indicates that expansion joints cannot be used in welding water supply steel pipes. However, their reason is not clear and it is difficult to confirm the stability of the steel pipe for a water supply pipeline. The purpose of this study is to determine whether or not an expansion joint is necessary to improve the stability of water supply in steel pipe through a displacement analysis of the pipework. The test results are as follows. Firstly, it was found that expansion and contraction of the water supply steel pipe (D 2,400 mm) occur repeatedly in 4 cycles per year, and the maximum expansion and contraction amount of the pipe is 13.03 mm in 1.24 km pipelines. Secondly, the thermal stress caused by expansion and contraction of the steel pipe is $13.7{\sim}36.1kgf/cm^2$ according to the burial depth (0~4 m). The main comparison factors to determine the stability of the steel pipe (STWW 400) were the allowable tensile strength and the fatigue limit, which were computed to be $4,100kgf/cm^2$ and $1,840kgf/cm^2$, respectively. Finally, the thermal stress of the steel pipe is very small compared to the allowable tensile stress and fatigue stress. Therefore, thermal stress does not affect the stability of the steel pipe, although the expansion and contraction of the steel pipe occurs by temperature changes. In conclusion, the study demonstrated that expansion joints are not required in water supply steel pipelines.