مجله مهندسی بهداشت حرفه ای
سال یکم شماره 3 (پاییز 1393)

The comfort lighting in the workplace provides employees visual health which can improve safety، visual comfort and enhance performance and product quality. The present study was conducted to evaluate general and local lighting in carpet weaving workshops in Bijar city.

In this descriptive analytical study، 101 carpet weaving workshops were randomly selected. The illuminance were measured based on the models and formulas presented in Illuminating Engineering Society (IES) using luxmeter model Hagner EC1 in height 76 cm from the ground surface. The local illuminances were measured in horizontal and vertical weaving level. Data were analyzed by SPSS software (version 16).

Research findings revealed the average of total and artificial illuminance level were 484. 5±458. 9 and 80. 0±49. 9 Lx respectively. Mean total، natural and artificial illuminance 39. 6، 57. 4 and 100 percent were lower the recommended 300 Lx levels. The average of minimum of local illuminance was less than 500 Lx in all workshops.

About 60% of workrooms had the acceptable general illuminance levels in middle day. However، due to the insufficient lighting sources in workshops، the artificial illuminance levels are unsuitable. Therefore، it is necessary to improve general illuminance levels by reform and repair artificial lighting systems or redesign them in carpet weaving workrooms.

Local exhaust ventilation system (LEV) is one of the most common engineering controls methods for the chemical agents in workplaces. This study aimed to determine the efficiency assessment of the LEV system for control of Fe2O3 dust in the process of oxide screen unit at iron making in steel industry. The LEV system with an extensive network of ducting including 17 hoods was investigated in a cross-sectional study. The First، variations and contradictions of the system and process were compared versus documentation (system plans)، then hood Efficiency Assessment accomplished by using of the dust concentration measurement besides of the each hood (source)، at two status ON and OFF of LEV system (Repeat three times)، by NIOSH 500 method. Result of statistical test between the concentration of pollutants at two status ON/OFF of LEV system، in 7 of 17 hoods، didn’t show significantly different (P <0. 05). Enclosed hood at the material falling from the tank to the feeder، with 85% efficiency and 3. 3±1. 5mg/m3 concentration at ON status was the highest efficiency. Two hoods، one enclosed hood at material falling from the Feeder into the screen and other unenclosed at material falling from conveyor to conveyor (small size at below screen)، both with 2% efficiency and the 243. 2±73. 5 and 3462. 4±1339 mg/m3 concentration demonstrated the lowest efficiency at ON status. Also the highest concentration of contaminants was at the unenclosed hood installed in the place of pellets falling from the conveyor into the tank with 5. 03g/m3 and efficiency of 7%. The few hoods of the investigated LEV did not have appropriate performance and had different efficiency. Even، some hoods (branches) show negative efficiency due to return of contaminant from the hood to workplace area.

To control and prevention of accidents، attention to root causes of accident occurrence is very important. Safety risk of process units located in metropolis، must be always under control and in accordance with risk acceptance criteria of the community. In this regard، the purpose of this study is identification of functional failures، root cause analysis and incident outcomes arising from gas release in the Town Border Stations (TBS). Using at the same time of both methods the Functional Hazard Analysis (FuHA) and Failure Mode & Effect Analysis (FMEA)، identification of the failure locations and qualitative risk analysis were carried out. For identification and analysis of the causes accident، Bow tie analysis method was also used. Occurrence probability of identified top events was 0. 71 and its failure rate was 1. 24 per year. Unsafe behavioral (FP=0. 36، λ=0. 446) and mechanical causes (FP= 0. 133، λ= 0. 142) had highest and lowest the contribution in the top event occurrence. Vapor cloud explosion (VCE) had the highest probability (0. 261) and failure rate (0. 243) among the all identified incidents outcomes. Prevention of the root causes and attention to the human factors have the considerable contribution in accident control in the process units. In the combined approach used in present study، if are considered to be، the barriers role against of the root causes and incident outcomes occurrence، it could be an appropriate approach for identification of root causes and control of the hazards process.

Approximately one third of all reported work-related incidents are triggered by manual handling. The proportion of incidents associated with manual handling in health and social care is 38%. Lifting and transferring patients is the task that is most often cited as a cause of manual handling incidents and of back injury in the healthcare sector. The aim of this study is to determine the MAPO index for remedial hospital wards of Qazvin and considering its relationship with incidence and intensity of musculoskeletal disorders among servers whose main task is manual handling of patients. In this cross sectional study، 54 cases of servers from 23 wards of 4 Hospitals was considered. The data was collected using the demographic characteristic questionnaire، the Verbal pain intensity scale، the Nordic questionnaire and the MAPO checklist. Statistical Analysis of collected data was performed with SPSS 22. One year prevalence of musculoskeletal disorders was 75. 9% and this amount during performing this study was reported 53. 7%. Regarding to different levels of MAPO score، just 5. 5% of surveyed personnel were in safe zone. 18. 5% of them exposed to moderate risk of musculoskeletal disorders and 76 % were at high risk. Also prevalence of musculoskeletal disorders incidents and pain intensity had significantly associated with the MAPO index score. Regarding to association between MAPO index score and prevalence of musculoskeletal disorders، to reducing incidences risk، improvement of MAPO index parameters to reducing its amount will be effective.

Worker exposure conditions such as noise level، exposure duration، use of hearing protection devices and health behaviors are commonly related to noise induced hearing loss. The objective of this study was risk assessment of influence factors on occupational hearing loss in noise exposed workers in typical noisy process. Information about occupational exposure of seventy workers employed in a noisy press workshop was gathered using the standard questionnaire. Audiometery test was performed using the screening audiometer (Model-Mevox). Afterward، the collected data was analyzed by using the Cox model in SPSS software. Based on results of the developed model، the job type and using status of HPD were most important features to induce hearing loss among workers. The risk of hearing loss among workers with the intermittent use of hearing protection was 3. 1 times more than workers used their devices continuously. Relative risk of hearing loss among smoker workers compared with non-smoker was 1. 1. The developed model could determine the effects of workers’ exposure conditions on risk of occupational hearing loss. This systematic approach can be considered as a helpful tool for determination the effectiveness of hearing conservation program and provide useful information for the managers and professionals in order to revise the existing health programs.

Shift work has been recognized as an important tool for organizing of work in developing countries. The disturbed sleep، fatigue and accident is the most common health ‐ related effects of shift work. The aim of this study was to evaluate the severity of fatigue and sleepiness between shift and non-shift workers and its relation to occupational accidents. This cross-sectional study was carried out in Sugar Factory located in Isfahan city. Using simple randomized sampling technique، 120 workers with an average age of 32 years for night work and 33 years for day work were selected. ISI and Epworhth questionnaires and Fatigue Scale were used to determine the prevalence of symptoms of Sleepiness and fatigue. The data was analyzed using SPSS20 software and applying descriptive statistics، Pearson correlation test and t-test. Results showed that the fatigue score among shift workers was 4. 41. In all symptoms associated with fatigue average scores of night shift were higher than day shift and there was a significant difference between them. There was a significant relation between the symptoms of fatigue with insomnia severity index and accidents. The rate of fatigue and the number of the work accidents was more in the shift workers compared with non shift workers. The rate of accidents was more common in people who had more severe drowsiness.

Exposure to heat is a significant problem in the Industries. The present study aimed at the evaluation of thermal risk، measurement of heat stress index، and proposing a plan for heat control in cutting and welding units in profile factory. The data of study was analyzed through the measurement of physical parameters with digital WBGT device and silvered Kata thermometer. Workers’ thermal comfort was calculated based on predicted mean voted (PMV) and predicted percentage of dissatisfied (PPD) with regard to the computed parameters. In order to control heat stress، an aluminum-insulated wall was used and airflow velocity was increased in cutting and welding units. The results of the WBGT index before and after the intervention using the shield were 30. 8° C and 23. 2° C، and by increasing airflow velocity were 30° C and 29. 5° C respectively. In addition، the obtained results for PMV and PPD by using the shield were 1. 38 and %44، and by increasing airflow velocity they were %90 and 2. 56 respectively. The results confirmed by using the shield the measured WBGT index was lower than the occupational exposure limit (28 ◦ c). The results showed that by appropriate designing and using control methods، such as insulation shield and increased airflow velocity، optimal thermal comfort based on national heat exposure limits could be reached.

Chemicals are serious harmful agents in the workplace، especially chemistry labs. This material may cause poisoning and different diseases. Laboratory hoods as first safety device protect laboratory workers against hazardous chemicals. This research conducted on chemistry labs in a petrochemical company for awareness of the hoods performance and proposed the needed reforms. In this study، in the studied laboratories، in order to evaluate performance of lab hoods، a capture velocity for 22 chemical hoods was conducted. Information concerning the structural characteristics of the baffle position، airfoil and opening area of hood s and situational characteristics their position relative to the air stream sources include general ventilation system vents، doors and windows of the laboratory were gathered. The mean velocity of hoods compared to the minimum acceptable value of 80 fpm showed that the only 9. 09 % of their hoods can provide an acceptable velocity. There was a significant relationship between the numerical value of the velocity and position features hoods structure (Pvalue<0/05). The results should that the structure of hood s and their locations in the studied laboratory concerning air flow sources must be corrected so that the velocity and performance of hoods being must provided and maintained.