Journal of Health and Safety at Work

Introduction: Emergency situations are of the major challenges in industries. Understading the status of inter-team interaction is effective in improvement of emergency response team (ERT). The purpose of this study was to investigate the interaction space of ERP in a refinery, using the social network analysis (SNA).

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Methods and Materials: In the present case study, the density indicator was used to examine the interaction space in the ERT. The obtained data were analyzed, employing UCINET 6.0 social network analysis program.

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Results: The findings showed that the ERT has the relatively low concentration with the density of 0.2 overall, the result reflect a low level of interactions among response reams at emergency situations management.

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Conclusion: The presented approach provided an appropriate image of interactions network among the emergency response teams. The social network analysis can be used for assessing the interactions of the emergency response teams.

Introduction: The most common standards being used for predicting the health risks of whole body vibrations are ISO 2631- and BS 6844, presenting frequency weighting anfd different coefficients for different sensivities in variuse axes. In yhis study, vibration was measured about 900 minutes on 9 trains in one of the active lines of tehran metro with the aim of comparing the mentioned standards in evaluating whole body vibation.

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Material and Method: In this research, in addition to evaluation of different kinds of vibration indicators, the differences of ISO 26331-1 and BS 6841 Standards have also been investigated. The amounts of r.m.s., vibration dose and daily vibration dose were measured in x, y and z axes for drivers seat and x axis for drivers back rest separately according to the instruction of the two standards.

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Result: The mean calculated values of r.m.s and vibration dose on a basis of 135 6841 standard were lower than those values calculated according to ISO 2631 standard. Moreover, the results showed that 3 cases, based on the ISO standard, had risk level of higher than 17 m/s1.75 and 3 cases, had risk level of higher than 15 m/s1.75 value, provided by BS 6841.

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Conclusion: Calculation according to the ISO 2631-1 standard show higher values. Indeed, ISO 2631-1 can provide a more secure criterion company to BS 6841, although the 15 m/s1.75 in BS is lower than the highest level of health guidance caution zone in ISO. Additionally, the association between r.m.s and vibration dose values in ISO 2631 is relatively lower than this association in BS 6841.

Introduction: The Power plants are as the major industries that have a large number of workers, providing they health is important. Exposure to occupational noise is the pervasive physical agent in industries like power plants and may impact health and for safety status for people. Determination of the sources of noise in workplaces is important step in noise control plans. This study aimed to assess noise pollution and determine the main sources of noise in a power plant for.

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Material and Method: This descriptive cross-sectional study was conducted on the ground floor of the turbine unit of a thermal power plant. Measurements was done based on the ISO-9612 and ISO-11200 standard using by the calibrated sound level meter model TES-1389 on “A” frequency weighting and “Slow” mode for time response. Surfer V.10 software was used for interpolation and noise maps producing. Based on grid method measuring for indicating of noise propagation, we set buffer of danger areas to determine main sources of noise. Also, we used the minimized grid method for measuring and study of noise denotation in vertical surface in each main sources.

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Result: The results showed that the measured indoor sound pressure level in all areas where at the risk category of the units. The highest average sound pressure level was belonged to the unit 2, with 93.1 dB(A). We find the feed water pumps were the main sources in all of the studied units. Among the four main components of the main sources, the highest noise levels associated with the main pump and the gearbox section with about 100 9B(L) and dominant frequency of 2000 Hz.

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Conclusion: Considering that feed water pumps had major sources in indoor power plant noise pollution, engineering noise control such as providing enclosures is necessary to reduce noise pollution to safe levels in the studied plant it is necessary.

Introduction: Gasoline is a complex mixture of more than 500 various hydrocarbons. The elimination of lead from petrol has been associated with the production of significant amounts of hepatotoxic and nephrotoxic monocyclic aromatic hydrocarbons such as benzene, toluene and xylene (BTX). The main purpose of this study was to ascertain whether or not exposure to unleaded petrol, under normal working conditions, is associated with any hepatotoxic or nephrotoxic response.

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Materials and Methods: This was a retrospective cohort study in which 200 subjects with current exposure to unleaded petrol working in Shiraz petrol stations as well as 200 unexposed employees were investigated. Using standard methods, atmospheric concentrations of BTX were measured. Additionally, blood and urine samples were taken from subjects for routine biochemical tests of kidney and liver function.

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Results: The geometric means of airborne concentrations of BTX were found to be 0.24, 0.37 and 0.64 ppm, respectively. The result of blood chemistry tests showed that means of direct bilirubin, ALT, AST, urea and plasma creatinine were significantly higher in exposed subjects than in unexposed employees, although all of these parameters were in the normal range. Conversely, serum albumin, total protein and serum concentration of calcium and sodium were significantly lower in petrol station workers than in their unexposed counterparts.

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Conclusions: The average exposure of petrol station workers to BTX is lower than the current TLVs for these chemicals. However, clinical significance and long-term results of observed changes in liner and kidney of exposed workers needs more evident in comparison with unexposed group.

Introduction: Safety culture is considered as the core of an organization’s safety management system. Safety culture is an organization ability to achieve higher standards of safety. The aim of this study was to investigate safety culture and its influencing factors and relation to the accident in a dam construction project.

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Material and Method: This cross-sectional study was conducted among 130 workers at a dam construction project. A standardized questionnaire included 59 questions was used to determine the level of safety culture. The accidents occurred in the project during the year were collected based on demographic characteristics. The collected data were analyzed using SPSS version 19.

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Result: The mean age of the subjects, their work experience and score of safety culture were 35.05, 7.5 Years and 183.2, respectively. Twenty seven accidents were recorded during the year in project. The most common cause of the accidents was indiscretions (33.3%). There was a statistically significant correlation between safety culture to occurred accidents and history of accident (P<0.05). The percentage of a positive safety culture of workers with an experience of accident (71.8%) was more than that of those with no experience of accident (45.1%). There was not a statistically significant correlation between safety culture and age, work experience, education, and marital status.

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Conclusion: It seems that safety culture on the project is influenced by the experience of accident and also it was strongly significant with the occurred accidents. Consequently, in order to create a positive safety culture in the workplace many factors including safety education program, work experience and accidents analysis should be considered.

Introduction: The present study aimed to test a model of the relationship between management commitment to safety and consciousness with unsafe performance,considering the mediating role of safety self-efficacy.

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Material and Method: Research design was the correlation throughStructural Equation Modeling (SEM) and the sampleconsisted of 265 employees of an industrialcompany who were selected by stratifiedrandom sampling method. Participants of this study completedsafety climatescale, short form of NEO personality questionnaire,safety self-efficacy scale, and unsafe performance questionnaire.Reliability and validity of the questionnaires were reported as acceptable. Evaluation of the proposed model was done by SEM through AMOS-21and SPSS-19 software packages. In addition, Preacher and Hayes’ SPSS Macro program was used for testing the mediating role.

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Result: The results showed that the proposedmodel fit the data properly.Management commitment to safety and consciousness had direct effect on unsafe performance and safety self-efficacy.Moreover, the mediating effect of safety self-efficacy in the relationship between management commitment to safety and consciousness with unsafe performancewas confirmed.

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Conclusion: Overall, organizations canreduce unsafe performance and consequently occupational accidentsby increasing the management commitment to safety and employees’ consciousness and also training of employees and supervisors to reinforce their safety self-efficacy.

Introduction: Prevention of accidents and work related diseases, are not allowed regardless of the safety of employees, customers, contractors and other persons. Assessment of individual safety management activities could reduce many losses. Present study aimed to evaluate the safety management of a household appliance manufacturing company.

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Material and Method: This study has done in a household appliance manufacturing company in Damavand city. Two questionnaires were firstly designed based on the weighted scores. The questionnaire 1 consisted of 4 indicators: Safety of machinery, Electrical safety, Risk assessment and Fire safety. Questionnaire 2 consisted of 11 sub indicators. Both questionnaires were completed by 30 HSE experts and supervisors. Reliability of questionnaires was based on cronbachs alpha coefficient. the safety status of each unit was determined and scored using information acquired by the questionnaires. Lastly, the safety of the entire company was determined.

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Result: Results showed that in safety management: the pressing and store house were in a good range of 66.66 and 60.12 points. Powder painting, enameling, laboratory were in a average range of 56.25, 55.92 and 54.15 points. Assembling and door storage were in a week range of 46.06 points.

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Conclusion: The findings showed that the safety status in the studied appliances company is in average range with 55.45 points. Therefore, it is recommended that the safety indicators should be improved for the betterment of the safety management in the company.

Introduction: The purpose of this study was to compare MORT and Tripod Beta methods, using a hierarchical model, in order to choose the best technique to analyze an event in an organization.

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Material and Method: In this study, a critical event was selected and the causes of the event were identified, employing MORT and Tripod Beta capabilities. Following the identification of the event causes, the aforementioned techniques were weighted and compared considering selected criteria and AHP hierarchical method.

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Result: Relative weights of the selected criteria were calculated. The ability to identify the event causes with the weight of 0.315 had the greatest weight. The event analysis cost (0.24), required time to analyze the event (0.146), technical experts (0.125), training for implementation (0.24), and availability of the analytical software (0.07) had obtained the subsequent weights, respectively.

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Conclusion: Analytic hierarchy process is an efficient and practical method to prioritize the choices considering the study objectives and criteria. As scientific method, Analytic hierarchy process helps the experts in decision-making. Considering the selected criteria, findings in this study showed that Tripod Beta technique (with a weight of 0.563) is superior to MORT technique (with a weight of 0.437).

Introduction: In the process industries, especially industries with hydrocarbons uses, due to flammability and reactivity of materials, high temperature, operation pressure, volatility and evaporability of liquid, fire and explosion hazard always has a great significances.The purpose of this study was to assess the quantitative fire safety using DOW’s fire and explosion index, in an oil extraction industry.

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Material and Method: The required information for conducting this research was obtained from process documents, DOW’s fire and explosion guideline,the measured operational parameters and also interviews and consultation with the supervisors and experts. Following, the study was conducted in three phases: 1) determination of DOW index, the radius and area of contact, 2) determination of loss control credit factor and finally 3) loss estimation.

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Result: Fire and explosion index in the understudy process unit was calculated 243.68 and thus severity of risk was extremely high and unacceptable. Radius of exposure and loss control credit factor wasobtained62.38 meters and 0.69, respectively. Finally,the most probable loss was estimated about 2863500 dollars.

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Conclusion: DOW’s fire and explosion index is a suitable technique to measure the fire risk of whole plant or a part of it. Thus, this criterion can be used to propose the changes or amount of protective equipment according to their effect in reducing the losses.

Introduction: Resilience engineering is a new approach in safety science. Its goal is to maintain organizational capacity in an acceptable level to help system in managing the crisis. Indeed, resilience engineering rely on systems abilities instead of weaknesses, and try to find indicators that help the system durability.

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Material and Method: In this study,first, 6 resilience engineering factors were chosen and sent toexperts in the form of paired comparison sheets. On the other hand, a valid standard questionnaire distributed among drilling rigs operational workers for measuring the NIDC resilience level. Finally,the priority of corrective actionswas determinedaccording to the score of the two analyzedquestionnaires.

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Results: The results of resilience engineering factors weighting showed that the management commitment has the highest value andthe second place belonged to the correct culture. The indicators’scores,based on the distributed questionnaires among workers, showed that all of the six factors had similar scoreswhich can be evaluated as fairly good. Finally, the results of prioritization of indicators ofresilience engineering, basedon the combination ofthe questionnaire and experts opinions showed that management commitment is the most effective resilience factor in the organization. .

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Conclusion: Management commitment and the current culture are the most importantcontributing factorsin company resilience level. Experienced workforce was the best strengthof the company and the effect of financial issues on resilience and safety was the biggest problem ahead.

Introduction: Heat stress is considered as a serious risk factor to the health and safety of workers in most working environments, especially in outdoor works and jobs that workers are exposed to heat due to the working process. This study aimed to evaluate heat stress among workers of brick-manufacturing units in Qom city based on WBGT index as well as the relationship between WBGT and physiological indicators.
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Material and Method: The present study was conducted in 40 brick-manufacturing units in Qom city. WBGT measurements were performed according to ISO7243 standard. Physiological responses of 184 workers (up to 5 people per unit) and also atmospheric parameters were measured. The physiological responses included oral temperature, skin temperature, and temperature for the carotid artery of the ear, heart rate, systolic and diastolic blood pressure. Statistical analysis was done using SPSS software version 16.
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Result: Mean WBGT index for various brick-manufacturing jobs including firing, manual material handling, working with conveyors, molding, and tempering were 30.8 °C, 26.74 °C 26.58 °C and 24.25 °C, respectively and the average WBGT was estimated 27.98 °C. WBGT levels measured in all units exceeded the level provided in ISO7243 standard. The highest mean WBGT was belonged to kiln section (30.8 °C). The mean WBGT at three heights of head, abdomen and legs were not statistically different (using t-test). The correlation coefficients between mean WBGT and mean oral, skin and ears temperatures were 0.203, 0.319, and 0.490, respectively, with the highest correlation belonged to the carotid arteries of ears. Moreover, WBGT showed no significant association with the mean heart rate, systolic, and diastolic blood pressure (P-value>0.05). Indoor and outdoor WBGT index was significantly different (P-value<0.05).

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Conclusion: The level of heat stress in all brick-manufacturing units was higher than the recommended limits, and the workers in kiln unit were more exposed to heat stress, in comparison with other units. Therefore, special countermeasures should be adopted to control heat stress for this occupational group.

Introduction: Nowadays in all human societies, sport is considered as a human-training matter, which often occurs in sport fields. Many people, including students in schools, occasionally deal with these fields. Therefore, a standard tool is required to frequently inspection of sport fields. The aim of this study was to standardize checklists for sport fields in schools.

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Material and Method: This study is a kind of tool and technique evaluation was done in Zanjan in 2013. The studied population included indoor and outdoor sport fields in governmental boys’ high schools in Zanjan city. The checklists’ items selected based on existing regulations, standards and relevant studies. Standardization of all tools was done applying the face and content validity and reliability tests.

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Result: The primary checklist for outdoor sport fields in high schools, which considered by the expert panel, consisted of 75 items. Based on CVI (2 to 3.9) and CVR (.5 to .78), modifications were done and 6 more items were added. And the same process for the primary checklist for outdoor sports fields (85 items) was repeated. Based on CVI (2 to 3.9) and CVR (.5 to .78), items increased to 92.

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Conclusion: The safety checklist for sport fields in schools are matched with the properties of them. The safety checklist developed in this study has an acceptable reliability and validity for useful applying in sport field inspections.

Introduction: Manual material handling (MMH) is the most common cause of work-related Musculoskeletal Disorders (MSDs). Prevention of MSDs is highly critical. The aim of this study was to assess risk of carpets manual handling by retail workers, and to implement ergonomic interventions in order to reduce risk of MSDs.

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Material and Method: This interventional study was conducted among 36 workers in 19 retailer sites of a textile corporation. Ergonomics assessment of the retailers was done using the comprehensive risk assessment model of the British Carpet Foundation. Moreover, the Nordic Musculoskeletal Questionnaire was used to determine the prevalence of workers’ MSDs. Reassessment was conducted after implementation of the ergonomics interventions.

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Result: The mean age and work tenure of participants were 36.28 and 16.2 years, respectively. The results of Nordic Questionnaire before intervention showed that overall 37.8% of the workers had experienced pain at least once during the past year, with the highest frequency belonged to the lower back (75%), shoulder (61%), and neck and upper back (55%), respectively. After implementing the interventions, the prevalence of MSDs reduced to 23.5%. The results of risk assessment before and after the interventions showed that of the 19 retailer sites, six sites were improved from poor to average state, and one site showed improvement from average to good condition.

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Conclusion: By implementing ergonomics interventions in carpet delivery sites, the risk factors of MSDs, induced by manual carpet handling, were reduced and safety and ergonomic conditions of the retailers were improved, compared to the previous conditions.

Introduction: Work conditions in kerbside ticket booths intensify the risk of health threats. In this research, it is aimed to introduce solutions for improving ergonomics conditions of these booths, by ranking and analysis the risk factors.

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Material and Method: Demographic information as well as physical, mental, and safety conditions of 47 booths are collected through questionnaires, interview and video recording. Following, critical index was identified using a hybrid method including QEC checklist, ANOVA statistical test and innovative methods for determining ergonomic indices. Improvement strategiesfor the critical index were analysed,using CATIA V5 R20 software and RULA technique, and solutions were presented.

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Result: Based on F-test at the 0.05 significance level, anthropometric characteristics and personal informationshowed no difference betweenmale and female vendors, except for weight. Comparison of ergonomic indices manifested the maximum occupational exposurefor physical-motor factors (45.39) and environmental factors (41.28). Additionally, the highest risks determined by Nordic questionnaire and QEC checklists belonged to arms and shoulders (38) and wrist (26). Three dimensional model of vender with current and suggested postures were analysed using RULA and accordingly it was found that risk levels were improved for right and left side of the vendor body from 7 and 5 to 3 and 1, and for customers from 6 to 1.

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Conclusion: Vendors of electronic ticket booths are exposed to musculoskeletal and environmental health threats, in Mashhad. Relocating the booths, adjustingcounterand desk height can significantly reduce the risk of mentioned hazards

Introduction: Patient safety is an important issue in regard to hospital servicesand any problem can cause adverse consequences. The purpose of this study was to assess the patients’safety culture at educational hospitals in Tehran.

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Material and Method: The present descriptive-cross sectional study was carried out among 312 health care workers in Baharloo, Amir Aalam, Shariati and Sina hospitals in Tehran, which were selected by cluster sampling. The participants were chosen randomly in each cluster. Safety Culture Survey questionnaire including 12 dimensions was used to assess patient safety culture. Cronbach’s alpha and test-retest coefficient were estimated 81 and 79 percent, respectively.

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Result: Nurses comprised 61 percent of participants in the study. 42% of staff had less than 5 years work experience. Of the 12 dimensions of patient safety culture, the frequency of reporting and exchange of information had the minimum average of 56 and 55, respectively. Moreover, the dimensions of organizational learning and expectations-management measuresobtained the highestmean score (69)among 12 dimensions of patient safety culture. Total mean patient safety culture in understudy hospitals was 63.

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Conclusion: It should be noted that paying more attention to the patient safety culture can lead to improve hospitals condition, as a whole, and to have a patient-friendly environment. Special attention should be paid to dimensions with the lowest mean score in order to strengthen them.

Introduction: Children have been known to spend most of their time at school. They learn their sitting habits in this period of time. Incorrect sitting postures and inappropriate school furniture can result in abnormalities in the vertebral column, back pain, neck pain, Fatigue and discomfort. Hence, this study was aimed to examine the match between students’ body dimensions and existing benches and desks dimensions in Hamadan female primary schools.

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Material and Method: In this study, 624 students of Hamadan female primary schools were investigated and some of their anthropometric dimensions including shoulder height, elbow height, knee height, popliteal height, popliteal-buttock length and hip breadth were measured. In this sense, a chair (with adjustable height, depth and elbow support) and a caliper with movable jaw were used for measurement of anthropometric dimensions. The measurements were performed in a way that thighs were in full contact with the seat, there was a right angle between the thighs and legs, the feet were in full contact with the movable pedal, the trunk was straight and the back and hips were in full contact with the backrest. Following, the match of the dimensions of existing benches and desks with the appropriate dimensions (based on the students’ anthropometric dimensions) were examined.

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Result: The results showed that the seat height, seat depth, seat width, back rest height, desk height, underneath desk height were in acceptable rangefor 10.1%, 17.3%, 5.6%, 53.5%, 1.9% and 31.1% of students, respectively.

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Conclusion: Despite differences in the body dimensions of primary school students, there is no regularity in using of school furniture. Overall, the dimensions of existing benches and desks are not matched with the anthropometric dimensions of students.

Introduction: Volatile organic compounds such as xylene, which are the main constituents of the oil and petrochemical industries, have serious impacts on health and can cause adverse effects on the environment. It is clear that release of these compounds into the environment should be controlled. The two-phases partitioning stirred tank bio-reactor is one of the newest methods for treating these compounds which have few side-effects besides of having appropriate efficiency since itdestroyscontaminant completely and transform it tosafer compounds.

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Material and Method: In this study, a two phase partitioning stirred tank bio-reactor, in lab scale, was used for treating the gas stream containing xylene vapors. The aqueous phase containing the bacteria Pseudomonas putida and nutrients inserted into the bioreactor with 3:1 ratio and system performance was evaluated for 432 hours in the concentration range of 1000 mg/m3 to 3500 mg/m3

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Result: Empirical findings of this study showed that the maximum, minimum and average of removal of xylene vapors by stirred two phase bioreactor containing a pure strain of Pseudomonas putida were 94.00, 54.00 and 84.94 percent, respectively.Furthermore, maximum, minimum and average of elimination capacity of xylene were obtained 93.00,24.00 and 62.02 g/m3/h, respectively

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Conclusion: Overall, the results of the present research revealed that the application of two phase stirred tank bioreactors (TPPBs) containing pure strains of Pseudomonas putida was successful for treatment of air streams with xylene.

Introduction: Neighborhood environment plays an important role in the health of residents. This study was conducted to assess health, safety and environment (HSE) in poor and rich vicinities in order to improve health levels of the neighborhoods, using Community-Based Intervention (CBI) approach.

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Material and Method: In the present field study, HSE variables were assessed by a checklist (NHSES) through observation, interviews with neighborhood residents as well as document review.Of the 374 vicinities in Tehran, ten regions were selected through cluster sampling. The Control Chart approach was used in order to compare the field data and the possibility of decision-making about the neighborhoods.

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Results: Overall, results showed that status of health, safety and environment in both rich and poor neighborhoods in Tehran was in the warning level.

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Conclusion: The CBI is an appropriate model for empowerment of neighborhoodsin a way that promote HSE status.

Introduction: The weaknesses of traditional hazard analysis methods lead to their inefficiency to utilization for modern socio-technical systems. System Theoretic Process Analysis (STPA), which is in the category of systematic analysis methods, has a powerful logic to identify hazards in such systems,as a suitable alternative method. This study aimed to analyze hazards associated with extinguishing systems of steam unit of a power plant, using STPA method.

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Material and Method: The present research is a qualitative case study. The related hazards were defined using STPA method.Following, the safety control structure diagrams in different parts were plotted and inadequate control measures and its causal factors were identified.

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Result: For steam unit of power plant, the most tragic incidents wererelated to hazards and risks of turbine device (switch the turbine cycle). Then, according to the plotted diagram for structure of safety control extinguishing systems associated with switching the turbine cycle, PLC system was determined as the most important part of the control system and operator was identified as the strategic and effective part of a control system. Following, more than 54 causal factors were identified, considering the relevant details about the risks analysis of the turbine.

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Conclusion: Due to its systematic structure,STPA method can be effective for a more complete identification of risks and causal factors which causing hazards in the emergency extinguishing systems. Therefore, development of such tools for those operators involved in safety-critical systems will be useful in terms of safety.

Introduction: Working in hot and inappropriate climate condition is one of the most common problems of occupational health which can lead to heat induced diseases and even death. Heat stress may impair the cognitive processes involved in decision-making and converting simple tasks to complex ones. The aim of present study was to assess selective attention and reaction time among workers in a casting unit of a car manufacturing industry and to investigate the effects of heat stress on mentioned variables.

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Material and Method: In this retrospective cohort study 70 workers from a hot industry were selected in two of exposed and control groups. First, demographic questionnaire was completed for each of the participants and noise and light were measured as the likely confounding factors. Stroop test 1, 2, and 3 were done before and during the work in order to determine the effects of heat on selective attention and reaction time. Besides,WBGT were measured at the ankle, waist, and head levels. Data were analyzed using SPSS software, version 18.

Result.: WBGT measurements showed that the mean WBGT were 33 and 16.7 for the exposed and not exposed groups, respectively. Moreover, no significant relationships were observed between test duration, reaction time, and number of errors in Stroop tests 1 and 2 and the level of heat (P-value<0.0001). However, the mentioned variables had a significant positive correlation with Stroop test 3. Additionally, for exposed group variables of test duration, reaction time, and number of errors in Stroop 3 were significantly higher than those of control group.

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Conclusion: According to the findings in present study, heat stress causes an increase in reaction time and a decrease in selective attention. Thus, heat can be assumed as a stressor in hot work environments and the heat should be taken into account while design of job and tasks which needed selective attention or reaction time.