• Fire Science and Engineering
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• v.15 no.2
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• pp.53-58
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• 2001

This study was undertaken to evaluate the performance of flame retardant for fire precaution from sparks at welding-cutting process in industry sites such as shipbuilding yard and chemical factory. As the results of the performance experiment, six kinds of welding blanket in samples that are used commercially had enough in the performance of flame retardant. Nevertheless, the performance to fire precaution un welding blanket shows that the coaling product of two kinds with fiber glass is not sufficient. The lower oxygen index to welding blanket is considered that it is more than 30 in domestic standard. We suggested that the performance improvement of flame retardant for welding blanket need continuously, and the guideline of the flame retardant to welding blanket should be considered and established.

• Fire Science and Engineering
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• v.26 no.3
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• pp.60-66
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• 2012

In this study, it was evaluated the fire risk during welding cutting tasks. Welding-cutting machines are representatively used at construction sites. Inverter AC/DC TIG welding macnine and inverter air plasma cutting machine were used in experiments. Temperature of spreaded cinders was measured using a thermal camera. Cinder sizes and spread range were measured according to the height and input current. It was also evaluated the fire risk during welding-cutting process, when flammable materials were located around the working area. There were used hay, dust fence, urethane foam, vinyl, paper and oil as flammable materials. Temperature of spreaded cinders was reached at about $450^{\circ}C$. Cinders were spread approximately 4.7 m, when a worker carried out cutting process at 2.5 m height. The possibility of a fire is very high, when flammable materials were located around the working area.

• Journal of the Korean Society of Safety
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• v.17 no.2
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• pp.69-75
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• 2002

Current fire safety in the construction sites has developed piecemeal over a considerable period of time. However, the law and regulation of fire safety is insufficient to protect fro in the construction sites. The frequency of fire in the construction sites is very rare but it brings longterm deterioration durability of building structure and large scale industrial calamity. There are many process of works and each work deals with many kind of flammable material, so it is very difficult to find a proper safety fire prevention. This study executed the questionnaire and fire experiment of the welding work to provide effective fire prevention counterplan.

• Fire Science and Engineering
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• v.16 no.3
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• pp.48-55
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• 2002

This study presents a treatment of suitable flame retardant through evaluating fire performance after treating flame retardant of fibers for development of welding blanket. The experimental samples used were commercial fibers and we are treated fibers with the flame retardant liquid and the flame retardant paint. The fire performance of the sample was carried out according to the Korea and Japan Standard. As the results of the fire performance experiment, the treated fiber in samples had enough in the performance of flame and fire retardant and the grade of their was from grade A to grade C according to flame and fire retardant standard. The lower oxygen index indicated that all treated samples with the resist are satisfied with international standard. We con-sider that the welding blanket treated with grade A, B and C performance prevents fire spread regardless of the height of work stairs in the case of installation horizontally. Also, it is considered that the welding blanket treated with grade C performance prevents fire spread regardless of the height of work stairs in the case of installation vertically.

• Korean Chemical Engineering Research
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• v.56 no.6
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• pp.811-818
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• 2018

A fire and explosion accident caused by a liquefied petroleum gas (LPG) welding and cutting torch gas leak occurred 10 m underground at the site of reinforcement work for bridge columns, killing four people and seriously injuring ten. We conducted a comprehensive investigation into the accident to identify the fundamental causes of the explosion by analyzing the structure of the construction site and the properties of propane, which was the main component of LPG welding and cutting work used at the site. The range between the lower and upper explosion limits of leaking LPG for welding and cutting work was examined using Le Chatelier's formula; the behavior of LPG concentration change, which included dispersion and concentration change, was analyzed using the fire dynamic simulator (FDS). We concluded that the primary cause of the accident was combustible LPG that leaked from a welding and cutting torch and formed a explosion range between the lower and upper limits. When the LPG contacted the flame of the welding and cutting torch, LPG explosion occurred. The LPG explosion power calculation was verified by the blast effect computation program developed by the Department of Defense Explosive Safety Board (DDESB). According to the fire simulation results, we concluded that the welding and cutting torch LPG leak caused the gas explosion. This study is useful for safety management to prevent accidents caused by LPG welding and cutting work at construction sites.

• Journal of the Korean Institute of Gas
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• v.24 no.1
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• pp.76-81
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• 2020

Recently, fire and explosion accidents caused by sparks scattered during welding and melting work in the work place where flammables are present. The causes of such fire accidents are mostly non-compliance with basic safety rules such as the removal of hazardous goods and the prevention of sparks scattering. It is strongly recommended to revise Industrial Safety and Health Act. This study analyzes the fire and explosion accidents in the work of firearms, such as welding and melting work, and analyzes the causes from a system perspective, and proposes an improvement plan for the system such as expanding the number of fire monitors, pre-approval of fire risk work, and intensifying fire prevention safety education.

• Journal of the Korean Society of Safety
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• v.34 no.3
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• pp.21-27
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• 2019

Many accidents have been occurring during welding and flame cutting work related to maintenance and repair as the domestic manufacturing facilities gradually become decrepit. However, it is not easy to find the accurate statistics and analysis data on accidents occurring during welding or flame cutting operations related to maintenance and repair of machinery and equipment. Therefore, in this study, the fatal accident cases of fire/explosion and asphyxiation that occurred during the welding and flame cutting work in the manufacturing industry were collected and their characteristics were analyzed. Then, we tried to find the connection of the accidents according to the machinery/equipment and the work content, and to provide the materials and measures that can be used to prevent the similar accidents. We collected 329 cases of the fatal accidents related to fire/explosion and leakage/contact of chemical substances in the domestic manufacturing industry during the last 10 years (2008 ~ 2017). Among them, 72 accidents occurred during welding or flame cutting were extracted and the related reports were investigated whether they occurred during usual work or unusual work. Also, the machinery/equipment and the work content related to the accidents were classified and analyzed based on the criteria. The analysis results showed that 31 cases of the fire/explosion accidents occurred during usual work and 32 cases during unusual work, and it was found that 9 cases of asphyxiation death occurred during usual work. Then, from the analysis results, the connections of the machinery/equipment and the work contents related to the accidents were schematized into a accident tree.

• Proceedings of the KWS Conference
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• 1996.10a
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• pp.45-46
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• 1996

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.563-568
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• 1999

Generally the control method of wire feeding motor in welding machine has been used full-wave phase control method. The fire-angle control generates low frequency speed ripple, and it causes the output current ripple. So it results in the variation of welding condition and low welding performances such as spatter generation and bead state. For the purpose of welding performances improvement by speed controller in wire feeding motor, in this paper the constant speed control method for welding machine is proposed. The proposed system is composed of speed control loop and current control loop. As a result of experiment by using proposed constant wire feed experiment by using proposed constant wire feed speed controller, the output voltage and current waveform and metal transfer are maintained stably. And moreover the number of instantaneous short circuit occurrence is reduced remarkably.

• Journal of the Korea Institute of Building Construction
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• v.20 no.4
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• pp.383-389
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• 2020

Accidents on construction sites involving fires do not occur as often as accidents involving falls from height or collapses. However, once a fire accident occurs, there is a high risk of a large number of casualties. Fire on construction sites is affected by working conditions and the types of activities the construction workers are engaged in at the sites. This study aims to identify activities and working conditions at construction sites that are vulnerable to fire, and analyse how they correlate with each other and how they affect the causes and consequences of fire accidents at construction sties. I analysed 40 fire accident reports and listed the situations vulnerable to fire at construction sites considering direct causes, activities, and working conditions. The most dangerous combination of fire hazards can be the heating devices used during rest/sleep in the office/cabin/storage during cold weather. The next most hazardous combination can be sparks arising from painting, waterproofing, insulation, plumbing, or welding/melting work in an underground or confined space.