Journal of Health and Safety at Work

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Introduction: Safety signs provide information as well as instructions concerning the hazard or dangers in the workplace. The correct comprehension of these signs is very important for doing the necessary feedback in the specific situation which they are described.

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Method and Materials: In this cross sectional study, the comprehension of 10 selected safety signs were investigated in 53 randomly selected employees of an industrial company in Shiraz. The comprehension test was carried out by aid a standard questionnaire obtained from ISO 9186-1:2007.

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Results: In this study the mean comprehension scores of the tested signs was 65.95 percent with standard deviation if 28.7. The highest and lowest comprehension scores were for “use hearing protectors” and “biological hazard” respectively. The comprehension of 40 percent of tested safety signs was lower than the minimum acceptable values of ISO 3864 and ANSI Z535.3 standards.

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Conclusion: This study showed that there is a significant difference in comprehensions of tested safety signs. For full comprehension of safety signs it is necessary to train the employees or adding supplementary text to the symbols in some cases.

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Introduction: Traffic transportation system despite of benefits is one center of accident.According to studies, human factors as unsafe acts and drivers mistakes are causes of accidenta happening. The main objective of this study was to Study of unsafe behaviors among city bus drivers in Hamadan.

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Method and Materials: This cross-sectional study was conducted in spring of 2011. Fifty four drivers were chosen using simple random sampling among Hamadan city bus drivers. The required data gathered by using safety behavior sampling technique. Data analysis was done with Statistical tests such as t-test and one-way ANOVA.

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Results: The study results indicated that %42.71 of driver’s behaviors were unsafe. Double Park (%24.71), speaking (%14.99) and unsafe grasping the steering wheel (%12.46) allocated to highest percentages of unsafe behaviors. Also it was shown the rates of unsafe acts were increased in younger and low income drivers, apparently.

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Conclusion: Because of high percent of unsafe acts and considering importance of its consequences in drivers, reducing unsafe acts trough investment and utilization of behavioral safety principles is required. In this regard, holding educational careers are suggested to increasing driver’s awareness.

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Introduction: Workers employed in outdoor occupations such as farm working, especially during rice harvest, are exposed to hot and humid environments that put them at risk for different kinds of heat-related disorders or heat stress. The aim of this study was to determine the susceptibility to heat-related disorders and prevention methods among a group of agriculture workers in one of the northern cities in Iran.

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Method and Materials: This study is a descriptive-analytical and cross-sectional study which was done among 340 agricultures workers in a city (Sorkhrood) in Mazandaran province. The samples were collected from 42 villages using two stage cluster-randomized sampling method. The data were collected by means of tailor-made data collection sheet and analyzed using descriptive statistical indexes and Chi- square test, and p<0.05 was considered as significant.

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Results: The findings indicated that the mean values of age and years of experience were 42.8 and 26 years, respectively. Almost half of the agriculture workers were overweight or obese, 34% illiterate, and 15% encountered chronic illnesses. Ninety five percent of the workers were not informed about prehydration in hot environment and none of them know about the consumption of electrolytes. According to Chi-square test result, there were no significant differences between the prevalence of headache as one of the early signs of heat –related disorders and other related factors.

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Conclusion: According to the results, agriculture workers based on their age distribution, education, body mass index, health knowledge, drug use and incidence of chronic diseases, are very vulnerable to heat-related disorders. Therefore, training on recognizing the early signs and doing control measures as essential element in heat stress prevention should be seriously considered.

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Introduction: Many methods exist for evaluating ergonomic risk factors for LBP at workplace, including biomechanical, physiological and psycho-physical methods. Digital Human Modeling (DHM) as a tool based on computer for ergonomic evaluation that Because having advantages such as saving time and costs in assessment and actively evaluation of ergonomic solutions in the digital environment.Aim of this study was evaluation occupational causes of LBP with the use of digital human modeling.

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Method and Materials: This study was a case quasi-experimental study in the engine assembly of the car manufacturing industry was conducted. First, The characteristics of job and risk factors for low back pain In all workstations were documented, then workstations with high risk of low back disorders were selected. Finally, a workstation for simulating and evaluating in the human digital modeling softwares, which includes 3DSSPP and Catia were selected. A total 22 posture of the lifting and lowering moment of the three tasks of workstation selected for simulation. After evaluation in the digital environment, the risk areas identified and solutions were presented.

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Results: The results showed that compressive and shear forces on the L5/S1 disc increased with increase of anthropometric dimensions and Horizontal distance from the body and decrease of height Lowering the site, and the percentage of people capable to perform a task in joint, decreased with increase of anthropometric dimensions. Ligament strain in postures with sever bending trunk were more increasing. RULA scores increased with the Unsuitable conditions of back and arms. High risk areas, were mainly related to the low height of pallets in lifting and lowering and high Horizontal distance from the body.

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Conclusion: According to The results of this study, Biomechanical Causes for LBP, including anthropometric characteristics (height and weight), Horizontal distance of object to the body, height of lifting and lowering location and trunk bending and torsion. This study showed that DHM is an effective tool in the evaluation of job tasks and workplace design, that can be identified risk area in each task and to achieve the ideal design. Using DHM can be implement Desired solution in a virtual environment and With the re-evaluation, Be sure of having effective solutions in the real environment.

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Introduction: Work-related musculoskeleta ldisorders (WMSDs) of upperlimbs (UL)in the last 35 years have become extremely widespread, reaching epidemiclevels, inalladv ancedindustrializedcountries. They are considered the main cause of disability, time off work, and requests for healthcare

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Method and Materials: For detailed risk assessment, ISO -11228-3 is the preferred method. It is recommended for the specific purposes of ISO -11228-3(2007) because, given the knowledge at the time of publication, it considers all the relevant risk factors, is also applicable to “multitask jobs”, and provides criteria - based on extensive epidemiological data - for forecasting the occurrence of UL-WMSD (upper limb work-related musculoskeletal disorders) in exposed working populations. In this method is the ratio between the number of actual technical actions, ATA, carried out during a work shift and the number of reference technical actions, RTA, for each upper limb, specifically determined in the scenario under examination.

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Results: Results shown in 4 workstations include 35 task in an automotive industry. One of them is red and another’s are green.

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Conclusion: This method is suitable, quickly and very easy to use for assessment of ergonomics situation in work.

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Introduction: Exposure to crystalline silica in the construction workers such as miners and diggers are widespread. Exposure to respirable silica (quartz) can results in silicosis. The goal of this study was to determine the contribution of each workers and component task to total dust and respirable quartz exposure in the tunnel of metro.

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Method and Materials: The assessment of crystalline silica and total dust was performed according to standard procedure ( NIOSH 7601).

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Results: Both total dust and quartz levels were high. The results of total dust in the digging process (37.63± 0.76 mg/m3) were higher than in the cement work ( 9.88 ± 0.80 mg/m3). The maximum 8 h time-weight average concentration for quartz was found among the digging workers (0.407± 0.006 mg/m3) , followed by the barbed workers (0.11 ± 0.008 mg/m3).

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Conclusion: It can be concluded that the total dust contains high amounts of crystalline silica and it is responsible for the occupational exposure to quartz in n construction workers. Thus, it is to be expected that the construction workers will suffer negative health effects due to exposure to the quartz dust.

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Introduction: Risk assessment of Toxic or hazardous chemicals enables the Industrial Hygienists to make the appropriate decision in providing healthy work place. This project was conducted in an assembling plant,(4workshop) of an Automobile Industry in IRAN with 2 types of welding operations, including GMAW (CO2 welding) and Spot resistance welding operations.

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Method and Materials: Welders` exposures were assessed via collecting 143 breathing zone air samples based on NIOSH 0500 method. Risk assessment was carried out using Singapore recommended method.

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Results: Finding showed that the mean of welders exposure in GMAW and Spot resistance welding operations 5.61 ± 5.78and 2.38± 2.15 mg/m3, respectively(p<0.05). The results showed that in GMAW welders had the highe exposure in comparison with Spot resistance welders (p<0.05). The findings also demonstrated that the risk rate of GMAW welders were high, while this rate for Spot resistance was low.

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Conclusion: more hygienic attention is needed for GTAW welders. Control approaches are required including effective engineering control, conduct air monitoring, biological monitoring training, adopt respiratory protection program, develop and implement safe and correct work procedures and finally reassess the risk after all the controls have been done.

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Introduction: This study was conducted to assess noise pollution in one of thepetrochemical complex andtakepractical measures to reduce it. Thecompanyis located in site 4 of Mahshahr Special Economic Zone.

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Method and Materials: In the first phase of the research, environmental noise was measured to determine the noise levelsin the different sections of the plant and also identify the main sound sources.Then,using the basic acoustic knowledge, aformulahasbeenproposedasan indexof noise control priority to select one section of the plant as the first priority forcontrolling noise. The main soundsource of the selected section wasknownby referring to noise maps and contours and finally its acoustic properties were analyzed.

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Results: The results showed that safety caution and danger areasof the plant under study were 16.7%, 74.5% and 8.8% respectively and a major part of the danger zone (about 54%) was related to unit Air. Noise level in 24 percent of the caution zone ranged from80 to 85 dBA and alsoitwas above 90 dBA in 33.4% of danger areas.

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Conclusion: Compressionsectionwhich was located in unit Air was knownas first priority based on Noise Control Priority Index.Dryer machineswere the main sound source in this section.

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Bazaars are most active and comprehensive center of urban life in Iran and according to its nature, have the economic and social functions. The nature and severity of risks associated with the quantity and quality of materials and enrgy available has led the growing importance of preventive safety assessment in Bazaars. The main objective of this study is to provide a model for risk assessment and management in urban Bazaars. After familiar with the studied systems, interviews with experts, using the Delphi method and paired comparisons, framwork of risk assessment and management was designed.The framework was tested and verified in Hamadan Bazaars. Results showed that the total risk of Hamadan Bazaars, 20.5% of zones in high risk area, and 79.5% were in cautious area. Using of 22 parameters to determine Bazaar zone risks and focus on total, preventive, detective and control risk was the strenght of this study.

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Introduction: Heat stress is considered as physical hazard, in working environments. The effects of working in hot environment include: muscle cramp, fatigue, loss of consciousness, perception and heat exhaustion.The purpose of this study was to evaluate heat stress and identify hazardous workstations in terms of heat stress in one of the Teheran's forging industries, using WBGT index.

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Methods and Materials: This Cross-Sectional study has been done in one of the forging industries of Tehran on five successive days during the warmest period in Summer 2010. for measurements, a calibrated WBGT meter according to ISO7243 standard was used. All workers who were exposed to radiant heat in this industry, had more than 3 years continuous work history, So they were well accommodated to the environment. For statistical analysis SPSS14 and Exell2007 software were used.

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Results: In this study, the WBGT of all workstations in the exposed to the furnace were estimated. the workstations average WBGTTWA were calculated 27.97°C, Which were higher than the threshold limit value according to ACGIH recommendation. The ANOVA and Post hoc(LSD) tests showed significant difference in the radiant heat (P-value<0.01), and WBGT index (Pvalue<0.05), between three different heights of the body. The observed differences between head and waist were not significant, but the difference between two heights and the ankle were significant.

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Conclusion: Heat stress in workers exposed to the radiant heat sources were higher than the Threshold limit value, which recommended by ACGIH. The results also indicated that the main problem were the radiant heat, especially in the head and waist height. Hence in order to decrease the radiant heat, some control solutions were Suggested.

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Introduction: Any disorders or injuries to musculoskeletal system due to working procedure or conditons would be considered as work-related musculoskeletal disorders (WMSDs). The present study aimed to evaluate body postures and main risk factors contributing musculoskeletal disorder in barbers in IRAN, SARDASHT

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Materials and Methods: This study is a descriptive – analytical and cross sectional study. Total number of the hairdressers in Sardasht city were one hunderd and ten people. Nordic questionnaire, camcorder and Reba checklist were used to collect required data.

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Results: Based on the demographic data 42.9 % of the studied people were male and 57 .1% were women with the mean age of 18.8±73.31 and 75.6±12.28, respectively. Elbow pain has the highest prevalence (90%) and it was 71, 70, 68, 66, 63, 56, 48, 45 percent respectively, in the neck, wrist . hand, shoulder, hip, thigh, back, foot, ankle, knee, back body regions. According to the posture assessment, 27.6% of the risks were in moderate to high levels of exposure as risk factors for the musculoskeletal disorders.

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Conclusion: High prevalence of upper extremity musculoskeletal disorders shows that inappropriate posture,improper use of work tools, and highly repetitive movements for long period in make up task are the main reasons for the er prevalence of upper limb disorders in this occupational group.

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Introduction: Needlestick (NSI) is a known serious treat and occupational exposure among health care workers especially nurses. Since nurses are the biggest part of healthcare workers, and considerable percent of NSI are preventable, we decided to determine frequency of NSI and some related occupational factors among a group of them.

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Methods and Materials: This cross-sectional project was conducted among all the nurses (340 nurses with at least one year work experience) in Babol and Amirkola educational and private hospitals (in north of Iran). The data were gathered by means of a tailor-made data collection sheet including personal information and some occupational effective factors, during autumn and winter. The data were analyzed with descriptive statistical indexes and Chi-square test.

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Results: Our result showed that the relative frequency of NSI among the nurses group (the mean age of nurses was 33.8±7.7 years old and the mean work experience was 10.3±8 years) was 59.7 percent. Chi-square test result indicated that there were significant differences between NSI in different groups of some personal and occupational factors including age, years of experience, training condition, and needle recapping(p<0.05).

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Conclusion: According to positive effects of training and negative effects of incorrect working habits, repetition and completion of occupational education is necessary.

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Background and Aim: According to the biorhythm theory when the phase shift from positive to negative and vice versa people experience a critical an unstable day that prone them to error and accident. The purpose of this study is to determine this relationship in one of the automobile manufacturing industry.

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Materials and Methods: At first 1280 person incident entered the study was reviewed and then the critical days of each biological cycle was determined using the software Easy Biorhythm Calculator for all persons.

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Results: This study showed that the frequency of accidents in critical days and negative section of physical cycle was more than expected. Also the frequency of accidents in critical days and negative section of emotional and intellectual cycles was less than expected.

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Conclusion: This study showed that the frequency of accidents in critical days and negative section of physical cycle was more than expected. Also the frequency of accidents in critical days and negative section of emotional and intellectual cycle was less than expected. Due to the physical nature of the work activities in the automobile manufacturing industry can be stated that the study showed that in physical work activities, frequency of accidents in critical days and negative section of physical cycle in which the person is not physically ready to do the job was more than expected.

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Background: Generally every different machines which are implemented in industries, agriculture and transport systems exposed human to excessive vibration. The produced vibration can reduce comfort and productivity and also cause adverse effect on human health and safety. Long term human exposure to high vibration levels may lead to physiological disorders.

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Material and methods: This paper presents the results of an experimental study which is done on 584 students of Tehran University of medical sciences. The data was gathered by interview and a validated questionnaire. In this study the stimulus was produced by a calibrated 3 axis vibrated seat. The voltage of stimuli was 90 and 95 V in two different frequencies of 20 and 25 Hz in two axis of x and y. During exposure the transferred whole body vibration was monitored by a calibrated whole body vibration meter.

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Finding: The results of this investigation showed that whole body vibration effect on mental disorder is significantly higher among female compared with that of in male. The disorder induced by frequency of 25 Hz was three times higher than that of produced by 20 Hz. The frequency of mental disorders was increased by rising vibration acceleration. It was also found that taller people are slightly less sensitive to the range of tested frequencies and acceleration compared with of shorter one.

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Conclusion: A significant relation between height and mental disorders was found in this study which can be used on whole body vibration exposure management.

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The safety of high risk jobs especially in oil refining activities is a major concern. In the present paper, the welding risks in Tehran oil refinery have been assessed using the Job Safety Analysis (JSA) and the effectiveness of the controlling methods have been investigated. A descriptive study was conducted on 33 risks of 10 welding tasks in Tehran oil refinery (north unit). After arranging the appropriate expertise team, tasks in the welding process were identified using two methods of viewing the process and interviewing with the welders. The risks of each task were then identified through viewing the process, interviewing the welders and completing safety checklists. Risk Priority Number (RPN) was used for risk assessment. RPN was estimated from Likelihood and Severity Numbers using Australia/New Zealand standard (AS/NZS 4360/2004). Risk assessment was conducted for existing and post-control conditions. The effectiveness of the controlling measures suggested by the expertise team was evaluated using appropriate statistical methods. The results revealed that in the existing condition, 27.3% of the studied risks have a RPN of 5 (with an extremely high hazard potential), 3% a RPN of 4 (with a high hazard potential) and 69.7% with a RPN of 3 (with a medium hazard potential). The results also revealed that with the application of control measures suggested by the expertise team, 21.2% of the studied risks will hold a RPN of 4 (with a high hazard potential), 6.1% will have a RPN of 3 (with a medium hazard potential), 48.5% with a RPN of 2 (with low hazard potential) and 18.2% will have a RPN of 1 (with a negligible hazard potential). Statistical tests revealed that the application of control measures, will reduce the average amount of likelihood, severity and risk priority numbers significantly (Pvalue<0.01).

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Introduction: Increasing the angle of curvature of the spine in the lumbar region is precursor from many musculoskeletal disorders. Therefore, the measurement of easy, fast and accurate angle of lumbar lordosis will an important role in the prevention of these discomforts. The purposes of this study are clinical examination, clinical examination, and Facilitate measurement of lumbar lordosis curvature and prevent unnecessary radiation exposure to individual body and design and manufacture of lumbar lordosis system. System designed in this study do not the risks and other methodological problems and is acceptable in compared with standard indicators of Delmax.

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Methods and Materials: In this study, surveyed lumbar lordosis 50 participants of male and female using system of the measurement lumbar lorsosis and findings were compared with results of delmax index.

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Results: The lumbar lordosis of natural based on Delmax index between 96% -94% and based on designed system is equivalent to 40 to 60 degrees. Participants had 78% of normal lumbar lordosis, 12% Kyphosis and 10% Lordosis. The sensitivity of system in identifying healthy individuals and patients 100% and 55.6% respectively and overall accuracy was 84% system.

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Conclusion: The designed system had acceptable of accuracy in comparison with standard Delmax index.

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Introduction: The purpose of this study was prioritizing the noise control methods using Analytic Hierarchy Process (AHP) technique in Hamadan glass industry.

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Material and Method: This is a cross-sectional – descriptive - analytical study. According to a survey of experts by questionnaire and Delphi method four criteria were selected including cost, efficiency, executive capability and not to interfere in the process and eleven alternatives for control options. Prioritizing of the items was conducted based on the study criteria as well as the importance ranking determined in this study.

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Result: The results showed all that consistently Ratios were less than 10 % and compatibility of answers has been confirmed. According to expert’s views, the criteria of executive capability (0.277) and using the barrier between the two main sections (0.111) have achieved the highest priority among the criteria and control methods, respectively.

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Conclusion: In this study a pattern of decision-making structure was introduced based on Analytic Hierarchy Process for determining the method noise control. This method can improve the decision making process and prioritizing noise control methods as an efficient and effective approach.

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Introduction: In addition to direct and indirect costs of occupational accidents imposing on production companies, they impact the productivity of labor, too. However, gaining more profits and having less costs is always the main concern among industrial managers. Considering safety measures can be effective way to reduce occupational accidents and costs as well as negative impacts on production systems.

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Material and Method: In this paper, a risk assessment method using fuzzy and MATLAB software is presented to determine the safety level of production environments. The main parameters of this model include three items: accident probability, accident severity and current safety level. For this purpose, the statistical data of accidents and their causes published by Social Insurance Organization have been used in this study. Furthermore, expert judgments of safety and health professional have been used to determine the severity of accidents. In the fuzzy method, the Mamdani deductive fuzzy model has been adapted due to its easy applicability. Application of the model has been shown using a practical instance.

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Result: The defuzzified value for RL is found to be 3.48. Linguistic risk level expression is 100% substantial high risk that is full membership for fuzzy average set.

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Conclusion: The application of the proposed method can reveal which safety items and factors are most important in improving workers safety, and therefore decide where to concentrate resources in order to improve the safety of the work environment.

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Introduction: Low back pain (LBP) is a common and costly health problem. It has high prevalence in nursing job and caused shortage of nursing staff. This study was conducted to determine the prevalence of LBP, knowledge level of LBP risk factors and assess relationship between LBP prevalence and nurses’ knowledge level of LBP risk factors among nurses of Shiraz University of Medical Sciences (SUMS).

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Material and Method: In this cross-sectional study, 118 randomly selected registered nurses participated from SUMS hospitals with at least one year of job tenure. In order to assess nurses’ knowledge of LBP risk factors, a self-administered survey questionnaire consisted of four parts was used as data collecting tool. Statistical analyses were performed using SPSS (version 11.5). Duncan, T-test and ANOVA tests were used for data analysis.

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Result: LBP prevalence rate was found to be 79.7% (94 nurses) during the previous year from which 12 nurses were male (63.2%) and 82 nurses were female (82.8%). Nurses’ knowledge level of LBP risk factors in different hospitals was not significantly different. The Results showed that nearly half of the nurses had poor knowledge about LBP risk factors and the remaining had good knowledge level. The main source of information about LBP risk factors among nurses were related to their university education.

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Conclusion: A high prevalence of the LBP was found among nurses working at SUMS hospital. Knowledge level of nurses about LBP risk factors needs improvement. In addition to university education, which is the main source of information of nurses about LBP risk factors, on-the-job training seems essential in this field.

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Introduction: Nowadays, in many different fields of chemical agents several experimental researches is being done on volatile organic compounds using gas chromatography, which is time consuming and expensive methods. Photo ionization detector as an alternative method is used by researchers in this field. This feasibility study was conducted to replace the photo ionization detector with gas chromatography.

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Material and Method: In this study, after making pre-determined concentrations of Xylene, the results of measurements using photo ionization detector and reference method were compared. This comparison was done in 4 humidity levels and 3 concentration ranges.

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Result: The results showed significant differences in photo ionization detector readout and the reference method. However correlation coefficient of two methods were more than 0.99 in all cases regardless of the humidity rate.

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Conclusion: Although the results obtained by the photo ionization detector are different from those extracted from the reference method in the current study, due to linear response of the method correlation coefficient was at good level. Consequently, in case of studying concentration changes in a research, this alternative method would be applicable, otherwise calibration of the photo ionization detector with the target material is recommended.