A variety of composite materials are applied to industries for the realization of light weight and high strength. Fiber-reinforced composites have different strength and range of application depending on the weaving method. The mechanical performance of CFRP(Carbon Fiber Reinforced Plastic) in many areas has already been demonstrated. Recently, the application of hybridization has been increasing in order to give a compensation for brittleness of CFRP. Target materials are UHMWPE (Ultra High Molecular Weight Polyethylene), which has excellent cutting and chemical resistance, so it is applied not only to industrial safety products but also to places that lining performance is expected for household appliances. In this study, the CFRP and UHMWPE of plain weave, which are highly applicable to curved products, were molded into laminated hybrid composite materials by autoclave method. The mechanical properties and the mode I failure behavior between the layers were evaluated. The energy release rate G has decreased as the initial crack length ratio increased.

Many electrical socket-outlet fire accidents take place not only in homes but in the offices each year. The causes are mostly faulty constructions, managerial problems and carelessness. Construction and managerial flaws can be resolved by regular or special inspections, but carelessness is not solvable through inspections. Such carelessness can be related to the consumption capacity of electrical socket-outlets presently, the rated current of electrical socket-outlets is based on 16A. However, even at 16A, the heat generated in the insulator of an electrical socket-outlet varies due to such factors as part damage and environmental conditions of use. To explore this situation, the study conducted an experiment to analyze thermal relationship by applying 10A, 20A, and 30A currents. To secure reliability, the study employed thermal analysis simulation and compared the thermal relationship in the same current value. The experimental and simulation values were found to be similar and therefore, diverse current values were replaced with the simulation. At 30A, the temperature was found to rise to at least $169.9^{\circ}C$ which had worked as a sufficient amount of energy to bring the insulation aging of insulator.

As industry is progressing and standards of living are improved, the demand of electrical energy is expected to grow 8-9% annually. Therefore, the importance of electrical fire prevention technology with the ability of the power supply is being emphasized. According to the statistics of fire in Korea, fire occurred about 45,000 cases annually, and electrical fire possessed about 20%. The electrical fire by poor contact has increased gradually, can be connected as great fire to secondarily induce short circuit and earth fault. Then analysis of heating causes of electrical connections between copper and copper alloy is needed. Also, detection and analysis algorithm of oxide at copper alloy are necessary. In this research, in order to understand the characteristics of oxide growth with rising resistance and heating, it is demonstrated that the oxide at electrical connections can cause fire due to arcing.

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.

Dry water is a core-shell structured powder which comprises a very fine water core covered with hydrophobic silica particles. Recently, the dry water has attracted attention as a new type of fire extinguishing agents. However, characteristics of the dry water as a fire extinguishing agent have not been revealed until now. To our best knowledge, this is the first work to uncover effects of particle size of the dry water on the fire extinguishing performance. Pristine dry water, which has heterogeneous particle size distribution, was carefully separated by sieving method into three fractions which were a small size (ca. $110{\mu}m$) fraction, a medium size (ca. $220{\mu}m$) fraction and a large size (ca. $400{\mu}m$) fraction. Microscopic observations confirmed the effective separation of dry water's particle size. In extinguishing tests of wood cribs fire, the medium size dry water showed most excellent fire extinguishing performance, as compared to other dry waters having small (ca. $110{\mu}m$) and large (ca. $400{\mu}m$) particle size. The good performance of the medium size (ca. $220{\mu}m$) dry water may be attributed to the balance between cooling effect of the water core and smothering effect of the silica particles. It is also revealed that small size dry water has poor flowability than large size dry water.

As the prefabricated shoring system structure, which is a temporary structure, is often collapsed due to various reasons during concrete pouring, and directly affects not only the safety of the workers but also the quality of the final building, it is necessary to ensure the safety. It is considered that the pipe supports which are widely used as the prefabricated shoring materials in the construction site do not satisfy the performance criteria in many cases. Therefore, this study investigated the detailed conditions for satisfying the performance criteria and suggested the factors for improving the quality control level in order to prevent collapse accidents due to pipe supports reused at the construction site, As the results of test in order to understand the effect of the pipe supports (V2), which are being reused in the field, on the performance by factor, the performance was evaluated to be high in case of the small female screw clearance and the supporting pin with 12mm in diameter or larger.

This study statistically analyzed the laboratory accidents by investigating 806 laboratory accident survey reports which were officially submitted to government from 2013 to June 2017. After comparing domestic and foreign accident classification criteria, the laboratory accidents were classified using KCD7(Korean Standard Classification of Diseases) and OIICS(Occupational Injury and Illness Classification System) criteria. For the type and part of injury, KCD7 classification criteria was adopted. And, for the cause and occurrence type of accidents, OIICS was adopted to analyze the laboratory accidents. Most of injuries happened to the wrist and hand caused by sharp materials or chemical materials. The analysis of accident cause showed that accidents resulted in medical practice and accidents from handtools and chemical materials such as acid and alkali frequently occurred. The major occurrence types of laboratory accidents was body exposure to the chemical materials such as hydrochloric acid and sulfuric acid. In addition, the accidents resulted in destroy of grasped object or falling object were frequently reported.

Precast members have relatively good quality because they are manufactured in an environment suitable for quality control. A typical precast method in which pre-fabricated segments are assembled in the field requires a joint. Although the joint is a small part of the member, it greatly affects the behavior and quality of the structural member. In the previous study of this paper, the flexural strength of a joint, which is generally applied to half-depth precast deck systems, was verified to have higher strength than the design requirement. In addition, the proposed joint has been verified to have higher strength by reinforcing the connecting rebar. However, even if the flexural strength of the joints is sufficient, excessive deflection or lack of fatigue performance is likely to cause cracks in the half-depth precast deck system. In this study, the serviceability of the half-deck precast panel specimens with joints was evaluated and the experimental verification was conducted to evaluate the fatigue performance of the joint without connection rebar. As a result, the serviceability such as deflection and crack width was found to be higher than the design requirement in all the specimens. In the fatigue test, the fatigue effect was insignificant even in the absence of connection rebar.

Lack of incident reporting culture has been pointed out as a potential risk factor across industries. Consequently, comprehensive understanding of the factors affecting the willingness to report (WTR) is necessary. However, our knowledge on the related studies are not enough to date and even most parts of the existing studies have focused on patient safety, which makes it difficult to universally apply the factors to all industries. Therefore, this study aimed to identify WTR factors in chemical plants and evaluate the influence degree of the factors. To do this, 45 candidate factors were summarized throughout the previous studies and surveying plant safety staff. A questionnaire survey was conducted for 614 all employees from 9 chemical plants which belong to one company, and finally 32 WTR factors were identified throughout 520 responses. Of these, 19 factors were consistent with the previous studies and 13 factors were newly identified. The most influential factor was 'Views on the necessity of incident reporting', and 'Reporting practice by outcome severity', 'Fear of vilification, conflicts, blame, or sanctions' were followed. This result not only suggests various WTR factors suitable for chemical plants, but also shows need to derive specific factors that are appropriate to each industry. An empirical study could be expected to increase incident reporting by using these factors and verify its effectiveness on injury rate.

The safety and health signs as an important communication tool can help employees recognize the harm and risk information and take proper actions easily and fast. This study investigated the management of safety and health signs in 75 workplaces and also conducted a survey for the level of subjective comprehension of safety and health signs with 150 employees in Korea. In total, 69 safety and health signs containing alternative signs by KS S ISO 7010 were used for the survey for the ease of comprehension. At the results, the frequency of education on the signs was relatively high, but it was difficult to systematically manage those in the small-sized workplaces. In addition, the results of the ease of comprehension survey showed that proportion of alternative signs was high in the upper rank, and also several alternative signs showed significantly high mean compared with safety and health signs. And the means of alternative signs tended to have higher at the categories of prohibition, instruction, and guidance. Although there are some methodological limitations, it is important that the recent management and the level of comprehension for safety and health signs were empirically identified.

The purpose of this study was to evaluate the effectiveness of a vibration feedback system in improving two safe seating postures of office workers. In addition, the relative effectiveness of positive and negative feedback procedures was examined. Participants were four office workers. The dependent variables were the percentages of time participants spent in the safe sitting postures including shoulder, back, and overall body positions during the experimental sessions. A multiple-baseline design counterbalanced across participants was adopted. For two participants, the negative procedure was introduced first after baseline and positive procedure was introduced in the next phase. For the other two participants, the sequence of introducing the positive and negative feedback procedures was reversed. The result showed that the vibration feedback system, regardless of the type of the procedure, was effective in improving the safe sitting postures for all participants. However, the difference between the two procedures was not clearly shown. The benefits of the automated observation and vibration feedback system in workers' safety were discussed.

The 7,993 cases of Survey Report of Fatal Industrial Accidents conducted jointly by the MEOL and the KOSHA for the recent seven years(2007-2013) were categorized according to personal and occupational characteristics, industry types, business sizes, job types, activities at the time accident, types of accidents, material agents(assailing materials), unsafe conditions, and unsafe acts. And it is found that among the 72.2 percent of fatal occupational accidents in the construction and manufacturing industries are caused by falling, sticking, bumping and being caught under objects & overturning. For this study, through the empirical analysis on causes of fatal industrial accidents, was used to identity high risk groups based on total data of 7,993 victims of occupational accidents. An annual fatal occupational injury (FOI) rate per 10,000 workers was about 0.47‱. The middle-aged group and the elderly group showed the highest FOI rates per 10,000 workers (0.73‱, 0.80‱), and the daily workers showed the highest FOI rate (1.46‱), and the craft and related trades workers showed the highest FOI rate (2.17‱). In case of industry type the mining industry (7.26‱) showed the highest FOI rate, followed by the sewerage, waste management, materials recovery and remediation activity industry (3.91‱) and the construction industry (2.71‱). The primary high risk target group that requires a strategy designed to reduce fatal occupation injuries caused by falling and bumping & contact(collision) is the construction industry, and the secondary high risk target group in the construction industry is classified as the equipment, machine operating and assembling workers in the construction industry, those aged 50 years old and above need the prevention measures against bumping & contact(collision) and being caught under an object & falling(objects), while those aged less than 50 years old need prevention measures against falling(persons).

Currently, the legal framework for installation of safety facilities has not been implemented for new multi-purpose business excluding 23 multi-purpose business types, and therefore, there is a high likelihood of large number of casualties in case of fire accident. At present, the new multi-purpose business can start its operation only with administrative actions of the licensing agencies and registration to the tax agency, and it is difficult that the fire department, which is a competent safety management department, makes intervention them in the same way as before. In addition, as the licensing agency has no authority to restrict the business due to insufficient implementation of safety facilities, a lot of civil complaints occur, which causes difficulties in changing concerned laws and regulations rapidly. In this study, it is considered to analyze the legal system, status of safety management of multi-purpose business, type of new multi-use facility and characteristics of fire risk. Based on such analysis results, this study will suggest the improvement plan to solve the blind zones in the safety management, which enables the multi-purpose business to be operated within the legal framework.

Chemicals Control Act have been strengthened to control more safely hazardous chemicals from 2015. In particular, the standards for the installation and management of handling facilities was enhanced with specific regulations depending on type of the facilities and the hazardous chemicals. However, some standards for handling facilities caused difficulties in implementing the strengthened standards due to various field conditions, such as lack of physical space. The Ministry of Environment is implementing Safety Assessment System (SAS) to solve these problems since 2018. However, many plants have difficulties in preparing alternative methods to pass the safety evaluation. The purpose of this study was to review and analyze the SAS and to suggest alternative measures in terms of management and technical aspects through the case study of hydrochloric acid storage tanks. The following safety solutions were suggested for handling facilities that had insufficient the space and capacity for the retaining wall due to physical space. Firstly, insufficient space was resolved by introducing equipment relocation or demolition, and retaining wall expansion. Secondly, the wall of the surrounding buildings was used as an alternative to the retaining wall with additional chemical resistant treatment. Finally, sensor installation and facility inspection were suggested as ways to improve chemical safety. Therefore, improvement of chemical accident prevention system is required not only in terms of facilities supplementation but also management aspect. The results of this study are expected to be available for similar facilities and will be based on the preparation of additional safety assessment as alternatives measures in the future.

This paper describes the work and results of the preliminary Probabilistic Safety Assessment (PSA) for a research reactor in the design phase. This preliminary PSA was undertaken to assess the level of safety for the design of a research reactor and to evaluate whether it is probabilistically safe to operate and reliable to use. The scope of the PSA described here is a Level 1 PSA which addresses the risks associated with core damage. After reviewing the documents and its conceptual design, eight typical initiating events are selected regarding internal events during the normal operation of the reactor. Simple fault tree models for the PSA are developed instead of the detailed model at this conceptual design stage. A total of 32 core damage accident sequences for an internal event analysis were identified and quantified using the AIMS-PSA. LOCA-I has a dominant contribution to the total CDF by a single initiating event. The CDF from the internal events of a research reactor is estimated to be 7.38E-07/year. The CDF for the representative initiating events is less than 1.0E-6/year even though conservative assumptions are used in reliability data. The conceptual design of the research reactor is designed to be sufficiently safe from the viewpoint of safety.