• Corrosion Science and Technology
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• 제19권2호
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• pp.89-99
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• 2020

The inhibition of pitting corrosion failure of copper sprinkler tubes in wet sprinkler systems was studied. First, an apparatus and technology for removing air in the sprinkler tubes by vacuum pumping and then filling the tubes with water were developed. Using this apparatus and technology, three methods for inhibiting the pitting corrosion of the copper sprinkler tubes installed in several apartment complexes were tested. The first one was filling the sprinkler tubes with water bubbled by high-pressure nitrogen gas to reduce the dissolved oxygen concentration to lower than 2 ppm. In the second method, the dissolved oxygen concentration of water was further reduced to lower than 0.01 ppm by sodium sulfite. In the third method, the sprinkler tubes were filled with benzotriazole (BTAH) dissolved in water. The third method was the most effective, reducing the failure frequency of the sprinkler tubes due to pitting corrosion by more than 80%. X-ray photoelectron spectroscopy analyses confirmed that a Cu-BTA layer was well coated on the inside surface of the corrosion pit, protecting it from corrosion. A potentiodynamic polarization test showed that BTAH should be very effective in reducing the corrosion rate of copper in the acidic environment of the corrosion pit.

• 대한안전경영과학회지
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• 제17권4호
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• pp.161-169
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• 2015

A fire sprinkler system is very important to extinguish fire in the building. The sprinkler system initiates sprinkler discharge if the detection system identifies a developing fire and opens the pre-action valve. However, pre-action fire sprinkler systems mainly installed in the underground parking lot at the apartment complex do not properly operate at fire if the connection type of fire sprinkler systems does not properly installed and operated. This study identified the relationship between fire dispersion & damage and the connection type of water supply in the sprinkler system from many fire cases at the apartment complex in South Korea. In addition, this study also identified the water supply differences and characteristics between South Korea and foreign countries. The main purpose of this study is also to improve the water connection types in the sprinkler system that can reduce the potential failures of pre-action valve operation through electrical signal system. The study also suggests the improvement plan for water connection types in pre-action fire sprinkler system that can minimize potential failure of pre-action fire sprinkler system. The suggestions for revising the fire safe standard in South Korea includes letting the water supply pipe of sprinkler system water inlet connect to the second side of pre-action valve and the water flow device that can minimize potential failure of sprinkler system.

• Corrosion Science and Technology
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• 제16권5호
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• pp.265-272
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• 2017

Inhibition of pitting corrosion of the copper sprinkler tubes by removing dissolved oxygen in water with sodium sulfite was studied on the wet sprinkler systems operated in 258 household sites. First, air in the sprinkler tubing was removed by vacuum pumping. The tube was then filled with sodium sulfite dissolved in water. Sodium sulfite was very effective in maintaining a very low dissolved oxygen concentration in water in the sprinkler tube for the observation period of six months. Water leakage from the copper sprinkler tube was reduced significantly by using sodium sulfite. Both pitting corrosion process and pitting corrosion inhibition mechanism were investigated by examining microscopical and structural aspects of corrosion pits formed in failed copper sprinkler tube. Pitting corrosion was caused by pressurized air as well as sediments such as sand particles in copper tubes through oxygen concentration cells. It was confirmed microscopically that growth of corrosion pits was stopped by reducing dissolved oxygen concentration to a very level by using sodium sulfite.

• 한국화재소방학회논문지
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• 제33권3호
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• pp.44-50
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• 2019

랙크식 창고 내에는 화재하중이 높은 물품이 수직으로 조밀하게 적재되어 있어 창고의 내부에서 화재가 발생되는 경우 현재의 스프링클러설비에 의해 유효하게 소화되기 어렵다. 이에 본 연구에서는 실물 규모의 랙크 구조물을 구축하고, 구조물 내부의 스프링클러헤드 종류 및 배치에 따른 화재실험을 통해 스프링클러설비에 의한 소화유효성을 확인하였다. 본 연구를 통하여 랙크식 창고의 내부의 화재를 유효하게 진압하기 위해서는 방수량 115 LPM 이상의 스프링클러헤드를 사용해야 하며, 동 스프링클러헤드를 높이 기준이 아닌 랙크 각 단마다 설치해야하고, 각 단의 가연물더미의 대각선 모서리 위치에 설치될 필요가 있다는 것을 알 수 있었다.

• 한국안전학회지
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• 제22권1호
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• pp.7-12
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• 2007

There are two kinds of design process for sprinkler system. one is pipe schedule system and the other is hydraulically designed system. We have inefficient results when we design by hydraulically designed system because the design process for sprinkler system is restricted by domestic fire code. Therefore, it is essential to do an introduction of hydraulically designed system which is based on engineering for enhancing reliability and efficiency of sprinkler system. This study presents points at issue by comparing and studying design standards of sprinkler system from Korea, Japan and NFPA, and presents improvement plans of national fire safety code of sprinkler system by processing, comparing and analyzing designs according to piping schedule and hydraulically designed system about domestic objects. Installation standards of sprinkler system have to be applied not by object buildings but by hazard classification. It is hard to design an efficient sprinkler system for fire control when water supply requirement of sprinkler systems allocated according to a size of a building because the same purpose but other buildings may request more water requirement or less. We should sublate the pipe schedule system from national fire safety code and need to introduce the hydraulically designed system. The pipe schedule system presents easy access because it is based on the forecasted engineering calculations but it is applied to only small buildings like NFPA due to its low reliability.

• 한국분무공학회지
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• 제20권3호
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• pp.175-180
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• 2015

A series of sprinkler discharging tests was conducted to measure the droplet size and its distribution of residential fire sprinkler heads. Droplet sizes in sprinkler spray were measured using a laser diffraction method for the flush, circular and pendent type sprinkler head. In this study, the $D_{v,50}$ of the flush type sprinkler heads were ranged between $530{\sim}1040{\mu}m$ and those of circular and pendent type were $988{\mu}m$ and $916{\mu}m$, respectively. The measured cumulative volume distributions were followed by a combination of the log-normal and Rosin-Rammler distribution which is widely used in the computational fire analysis and the parameters of distribution function were obtained from the best fit line through the measured data.

• 한국화재소방학회논문지
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• 제16권1호
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• pp.24-29
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• 2002

본 연구는 배관에서의 정확한 압력손실과 유량을 측정하기 위하여 스프링클러 시스템중 격자배관방식에 대한 수리계산 프로그램을 개발하는데 그 목적이 있다. 본 프로그램 개발은 배관망 해석방법 등 여러 가지 자료로 근거하며, 격자배관방식이 국내에서 현행 시행되고 있는 규약배관방식의 단점을 보안하여 스프링클러 시스템을 성능기준화재안전설계로 이끌어 내기 위함이다. 소화설비의 전산화로 인한 작업의 편리성과 정확한 계산을 측정함으로서 전진적인 화재안전설계를 이룩하게 될 것이다. 이러한 프로그램의 개발은 미국 등에서 먼저 이루어져 오고 있으며 국내에서의 소방에 대한 발전이 한 단계 발전되는 계기를 마련하게 될 것이다.

• 한국화재소방학회논문지
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• 제26권1호
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• pp.102-112
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• 2012

본 연구에서는 건축물 외장재 화재 시 수직화재에 대해 화염의 수직확산 방지 및 지연을 위한 외벽방호 스프링클러 설비 구성에 관하여 연구하였다. 본 연구에 앞서 관련 수직확산 방지용 스프링클러 헤드의 개발이 이루어졌으며, 적용된 스프링클러시스템은 NFPA13의 연소확대방지시스템에 명기된 방사압 0.05 MPa와 유량 60 l/min를 도입하여 적용하였다. 시스템 설계를 통하여 소방대상물에 적용하였으며 본 시스템은 감지시스템과 연동하여 자동과 수동으로 작동하도록 하였다. 또한 외벽방호 스프링클러 설비의 유용성 평가를 위해 실물실험을 실시하여 외벽의 냉각효과와 화재의 지연을 확인할 수 있었다.

• 한국분무공학회지
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• 제28권2호
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• pp.97-104
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• 2023

A sprinkler is a fire suppression system that extinguishes combustible materials in the early stages of a fire, creating a spray. However, spray formation method of the sprinkler can result in an uneven distribution of water spray on the surface of combustible materials. It is necessary to ensure a consistent water flux density regardless of the spray direction and angle. In this study, the water flux distribution was analyzed for the various types of sprinkler head: circular, flush, pendent, and upright types. All sprinkler heads have a K-factor of 80 LPM/(0.1MPa)^0.5. In this study, water collection cubes were used to examine the water flux distribution. The upright type sprinkler head showed a low standard deviation in total sprayed area, indicating a high level of uniformity. The upright type head showed the lowest standard deviation in the radial direction, and also showed the lowest standard deviation in the azimuthal direction. Upright sprinkler head has no obstructing structure along the path of droplets after they are generated. For this reason, upright sprinkler head showed the most uniform water flux distribution on the floor.

• 한국화재소방학회논문지
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• 제20권2호
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• pp.8-13
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• 2006

제연설비와 스프링클러설비의 필요성을 확인하고 연기확산 가능성을 조사하기 위해 청정실 화재의 시뮬레이션을 수행하였다. 바닥면적 $39m{\times}13m$, 높이 4 m의 작업구역에 1MW의 메탄올 화재가 발생했을때, 제연설비와 스프링클러설비의 정상작동과 작동실패에 따른 연기누출 여부를 조사하였다. 제연설비가 정상적으로 작동하는 경우에는 스프링클러설비에 관계없이 연기가 안전하게 배출됨을 알 수 있었다. 화재확산과 연기발생을 억제하고 발생한 연기를 신속히 배출하기 위해 스프링클러설비가 필요하며, 스프링클러설비와 제연설비가 신속하게 작동할 수 있도록 신뢰도가 높은 스프링클러설비 헤드와 자동화재탐지설비가 필요함을 확인하였다.