• International Journal of Safety
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• 제7권1호
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• pp.35-38
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• 2008

The purpose of this study is to extract typical body shape of Korean VDT workers based on the three-dimensional Korean shape data and recommendation supported by Korea Occupational Safety & Health Agency during VDT task. Desirable desk heights and chair heights for the selection of the VDT working posture is proposed by analyzing moment, compression and joint shear for lumbar and spine of Korean adult(male and female). The desirable heights for desk and chair can be selected by the least load method during VDT tasks. In the current work the figures of Korean 50th percentile offered by CATIA-HUMAN are used as the average body type of the grown-ups and this research is accomplished with the recommended size of all working attitude such as the height of a monitor except for the height of desk and chair and the degree of watching the monitor.

• 한국직업건강간호학회지
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• 제11권2호
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• pp.121-131
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• 2002

Objective: The purpose of this study was to determine the physical load by identifying harmfully working postures and to develop recommendations for improving the existing situation with nurses in ICU, thereby to provide the basis for development of work-related musculoskeletal preventive program. Method: Various types of tasks were recorded with a video camera to chart and analyze different postures by OWAS(Ovako Working Posture Analysing System). Collected data showed that poor postures were adopted, not only for lifting or repositoning a patient, but also for other tasks. Data Analysis: The performed activities were then divided into Nursing Intervention Classification. Altogether 128 postures were selected for analysis. Then they were classified into different OAC (OWAS Action Categories). From all the observation, unhealthy postures, for which corrective measures had to be considered immediately (i.e., 75% classified as OACII+III+IV) were found. Collected data were analyzed in terms of percentage, 2-tail Mann-Whitney U test. Result: Poor postures mainly occur during 'positioning the patient' and 'airway suctioning' in NIC. No difference was found (p=0.060) between the percentage of harmful posture adopted during the patient handling tasks and non-patient handling tasks. Conclusion: This study shows, that in the nursing profession with ICU not only occur during patient handling, but also during other activities. The OWAS method was useful in determining the physical load by locating potential activities due to harmfully working postures, providing a detailed description with analysis, and suggesting successful means to reduce postural load.

• Wind and Structures
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• 제19권1호
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• pp.1-14
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• 2014

Rail-mounted cranes can be easily damaged by a sudden gust of wind while working at a running speed, due to the large mass and high barycenter positions. In current designs, working rail-mounted cranes mainly depend on wheel braking torques to resist large wind load. Regular brakes, however, cannot satisfactorily stop the crane, which induces safety issues of cranes and hence leads to frequent crane accidents, especially in sudden gusts of wind. Therefore, it is necessary and important to study the braking performance of working rail mounted cranes under wind load. In this study, a simplified mechanical model was built to simulate the working rail mounted gantry crane, and dynamic analysis of the model was carried out to deduce braking performance equations that reflect the qualitative relations among braking time, braking distance, wind load, and braking torque. It was shown that, under constant braking torque, there existed inflection points on the curves of braking time and distance versus windforce. Both the braking time and the distance increased sharply when wind load exceeded the inflection point value, referred to as the threshold windforce. The braking performance of a 300 ton shipbuilding gantry crane was modeled and analyzed using multibody dynamics software ADAMS. The simulation results were fitted by quadratic curves to show the changes of braking time and distance versus windforce under various mount of braking torques. The threshold windforce could be obtained theoretically by taking derivative of fitted curves. Based on the fitted functional relationship between threshold windforce and braking torque, theoretical basis are provided to ensure a safe and rational design for crane wind-resistant braking systems.

• Safety and Health at Work
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• 제11권3호
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• pp.335-346
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• 2020

Background: Nursing service is a nonroutine work with an excessive physical load and diverse tasks. This study derived representative common tasks based on the frequently occurring tasks with a high physical load in the nursing workers' daily work and developed indicators to evaluate the work risk by reflecting the characteristics of nonroutine work. Methods: Common tasks were classified through the following stages: literature review, first focus group interview (FGI) with experts, first classification of common tasks, second FGI with hospital health managers, a survey of nursing service workers, and the final classification of common tasks for each task type. To develop an objective risk index for physical load assessment, we investigated the frequency and duration of the derived common tasks via survey. Results: Nursing common tasks were categorized into six task types and 56 subtasks. To evaluate the risks of various tasks in nonroutine works, three frequencies and three working time levels were defined by examining the task frequency and working hours. Exposure time was defined to reflect the characteristics of a nonroutine job. The final risk assessment was the product of the exposure time level and job intensity level. From this, four risk action levels were derived. Conclusion: This study has the advantage of solving the problem of focusing on some tasks in evaluating the physical load. It was meaningful in that a new risk assessment index based on exposure time was proposed based on the development of an evaluation scale for frequency and time by reflecting the characteristics of nonroutine work.

• 한국기계가공학회지
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• 제20권5호
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• pp.111-120
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• 2021

A tractor is an agricultural machine that performs farm work, such as cultivation, soil preparation, loading, bailing, and transporting, through attached working implements. Farm work must be carried out on time per the growing season of crops. As a result, the reliability of a tractor's transmission is vital. Ideally, the transmission's design should reflect the actual load during agricultural work; however, configuring such a measurement system is time- and cost-intensive. The design and analysis of a transmission are, therefore, mainly performed by empirical methods. In this study, a tractor with a measurement system was used to measure the actual working load in the field. Its hydro-mechanical transmission was then analyzed using the measured load. It was found that the velocity factor, load distribution factor, lubrication factor, roughness factor, relative notch sensitivity factor, and life factor affect the gear strength of the transmission. Also, loading conditions have a significant influence on the reliability of the transmission. It is believed that transmission reliability can be enhanced by analyzing the actual load on the transmission, as performed in this study.

• 한국안전학회지
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• 제8권1호
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• pp.21-28
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• 1993

Occupational Safety & Health Code requires to calculate Design Load and stress for the approval within thirty working days prior to initiating each construction site work This study is to develop an easy and useful program that each safety manager. Controller or engineers are able to make output for the above mentioned form structure analyses without knowledge or engineering background of it. Therefore. three, randomly selected. different major student and engineers verified if they could make output. really without the engineering background. And then some deficiencies are corrected after finding those from the program operation.

• 한국안전학회지
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• 제14권3호
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• pp.174-180
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• 1999

The objective of this study was to investigate the effects of carrying postures and weight of load carried one time on a worker when carrying heavy loads. Six male students participated in this study to perform a manual materials carrying task as subjects. To make comparison of work loads with physical work capacity, maximal oxygen uptake measurement tests were performed with submaximal test. The average oxygen consumption for the tasks of this study was 27.59~31.93% $VO_2$max. The results showed that the weight of load carried one time affects on working heart rate and oxygen consumption($VO_2$). It was found that the workload was significantly lower when handling a 20kg load at a frequency rate of 3times/min than when handling a 40kg load at a frequency rate of 1.5 times/min. There was no difference between carrying postures. It is concluded from the results of this study that the workload can be reduced by controlling conditions of a manual materials handling task.

• 대한안전경영과학회지
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• 제10권2호
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• pp.95-103
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• 2008

The package loading process of the lumbering industry is an operation that after a pair of workers bind three or six lumbers into one unit and cut both ends of the lumbers, transports the weight cargo of 30-50kg by one meter, pack and load at a height of 1.2 meters. This package loading process causes lots of noise and wood dust when workers carry out the heavy work as the above. Therefore we developed the monolithic both ends cutting package loading equipment in order to prevent from getting musculoskeletal disease. An loading bar working system of this equipment is improved from pneumatic pressure system to oil pressure system, furnished the newly designed flow dividers, and developed the new system that a both end array is loaded identically. Also we developed the safety equipment of loading bar in order to prevent workers mistake and overload from malfunction during the package loading process. The main cause of job evasion on working place could be solved by preventing the musculoskeletal disease and improving the working environments.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2008년도 춘계학술대회
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• pp.135-147
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• 2008

The package loading process of the lumbering industry is an operation that after a pair of workers bind three or six lumbers into one unit and cut both ends of the lumbers, transports the weight cargo of 30-50kg by one meter, pack and load at a height of 1.2 meters. This package loading process causes lots of noise and wood dust when workers carry out the heavy work as the above. Therefore we developed the monolithic both ends cutting package loading equipment in order to prevent from getting musculoskeletal disease. An loading bar working system of this equipment is improved from pneumatic pressure system to oil pressure system, furnished the newly designed flow dividers, and developed the new system that a both end array is loaded identically. Also we developed the safety equipment of loading bar in order to prevent workers mistake and overload from malfunction during the package loading process. The main cause of job evasion on working place could be solved by preventing the musculoskeletal disease and improving the working environments.

• 한국안전학회지
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• 제25권1호
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• pp.57-61
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• 2010

Formwork is a temporary structure that supports its weight and that of fresh concrete as well as construction live loads. Scaffoling is a temporary frame used to support people and material in the construction or repair of buildings and other large structures. It is usually a modular system of metal pipes, although it can be made out of other materials. Bamboo is still used in some Asian countries like China. The purpose of a working scaffold is to provide a safe place of work with safe access suitable for the work being done. In construction site, steel pipes are usually used as scaffolds. In this study, scaffolding systems which is changed according to sleeper and joist space were measured by buckling test. Buckling load of respective scaffolding system was analyzed by structural analysis program(MIDAS). Buckling load of scaffold with/without wall connection and footboard was got by test and structural analysis. According to these results，we know that scaffolding system of case 3 is suitable. Buckling load of scaffold with wall connection is higher than without wall connection. So wall connection is important in scaffoling systems. Footboard in the scaffolding systems is not effective against promotion of buckling load. Finally, the present study results will be used to design scaffolding systems safely in the construction sites.