فهرست مطالب

  • سال پنجم شماره 1 (بهار و تابستان 1387)
  • تاریخ انتشار: 1387/02/11
  • تعداد عناوین: 11
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  • H. Naeini, M. Amiri, M. Nilfroshan, M. Khoram Page 6
    Background And Aims
    Ergonomics is a multidisciplinary science dealing with fitting the tools and environments to human. One of the propounded subjects in ergonomics is anthropometry, which measures the human body dimensions in order to have the appropriate dimensions between the equipments and the users.. Using anthropometric measurements, valuable data will be achieved which eventually leads to national and regional standards. The main objective of this study is designing anthropometric tools for static anthropometry measurements.
    Methods
    Available samples were assessed based on interview with experts in different disciplines and also literature review in on-line databases. Following the assessment of local and exported samples, and according to the analysis of social, environmental, market, practical, static, structure, assembling and material, systematic, standard and packing aspects, the characteristics of an anthropometry device were determined.
    Results
    Examining the pros and cons of available local samples in several academic centres, this was revealed that anthropometry portable devices should be produced in larger amounts so as to reach the goals.
    Conclusion
    In this study, a portable anthropometry device was designed for mass production according to anthropometric characteristics of Iranians. This device, due to the design, unique specifications, easy to use, lightness, few pieces used, and suitable costs, could be used in different places.
    Keywords: Static Anthropometry, Portable, body segment
  • E. Habibi, N. Amini, S. Porabdian, M. Rismanchian Page 15
    Background And Aim
    Macro ergonomics is a social - technical attitude which in the manner of top down proceeds to look at organization planning, work- system and also planning of human - machine, human -environmental, human- job interaction and emphasizes on employees participation and make plenty use of it.
    Methods
    This descriptive - analytical study is of cross - sectional type. Data gathering method is based on observation and questionnaire. The society under study includes 83 personnel (employees) of a factory which is a subsidiary of Iran Khodro. We used two questionnaires in this study. One is questionnaire to verify macro ergonomic situation which planned and consisted of 30 questions that investigated different factors in working environment and was verified in terms of stability and reliability (cronbach alpha = 0.72) and the other one was Minnesota job satisfaction questionnaire which was distributed among people.
    Results
    This research shows over 1,500 extended hour's male workers, 69 percent of whom reported "Chronic or Frequent" back pain, while 52 percent reported "Chronic or Frequent" wrist pain. Sleep deprivation could possibly be damaging in terms of muscle, ligament, or tendon injury. With the average extended-hours employee sleeping only 5.1 hours to 5.5 hours each day when working a night shift, they could face an increased risk of ergonomic injuries. The mean age of people under investigation is 30.8. Most people are in age group of 26-30 (44.6%) most individuals have 4 to 7 years working experience (56.6%). Macro ergonomic mean score in total society under study was obtained as 59.8. The highest score of job satisfaction has been related to middle managers (69.2). Pearson correlation test showed that there was a direct relationship between general domain of macro ergonomic and job satisfaction.
    Conclusion
    There is a consistency between main enhanced results in our study in terms of macro ergonomic situation with the result of similar studies of barariyan (2006) and rajabzadeh (2002) that have used RSI (Relative Stress Index). Also there is a correlation between the result of our study job satisfaction with the results of similar studies such as Bassy's (2002) in Swedish employees, Garcia and Molina's (1999) in Spanish employees and the result of Partovi study (2006) in Esfahan steel plant employees and Davari's (2003) in employees of Esfahan Shahid PowerStation.
    Keywords: Macro ergonomic, Micro ergonomic, working hours, work satisfaction
  • Sm Hazavehei, Sh Shadzi, T. Asgari, S. Pourabdian, A. Hasanzadeh Page 21
    Background And Aims
    Every year 50-158 million occupational diseases and job accidents occur in the world. Studies on the job injuries show that about 150000 injuries occur annually in Iran. Unhealthy behaviors are important problems in public health. Education is one of the best ways to change unhealthy behaviors. Interventions based on model and theories have many capacities for behavior change. Health Belief Model is one of the health education models that are useful for behavior change. This research has been performed in order to assess the effect of health education program based on health belief model (HBM) to prevent occupational respiratory diseases in workers.
    Methods
    Aquasi-experimental design was used for this interventional study, in which 88 of workers of Borujen industrial town participated, who were randomly assigned to experimental and control group. Data collecting tool were a self-administered questionnaire including 53 questions based on health belief model that was completed by the workers, in addition to the performance check list which was conducted by researcher via insensible controlling the worker's safety behaviour. Validity and reliability of the tools were examined prior to the study. Educational intervention was conducted in the first stage following by the second data collection one month later. The data of both experimental and control group were compared statistically before and after the intervention.
    Results
    The results showed that the mean of the grade of all parts of health belief model (HBM) and performance mark of the workers about safety and use of personal respiratory preventive equipment in experimental group after educational intervention compared to prior the study and also compared to control group were significantly increased.
    Conclusion
    The results of this survey showed that by enhancement of health belief model (HBM) components including perceived susceptibility, perceived severity, perceived barriers and perceived benefits, adopting preventive actions increases, too. Therefore, the results of this survey confirm the effectiveness and efficiency of health belief model (HBM) in safety education and adopting preventive actions of respiratory occupational diseases in worker's behaviors.
    Keywords: safety, Health Belief Model, personal protection respiratory equipments, education
  • A. Ghahramani*, J. Adl, J. Nasl Seraji Page 31
    Background And Aims
    Prevention of potential accidents and safety promotion in chemical processes requires systematic safety management in them. The main objective of this study was analysis of important process equipment components failure modes and effects in H2S and CO2 isolation from extracted natural gas process.
    Methods
    This study was done in sweetening unit of an Iranian gas refinery. Failure Mode and Effect Analysis (FMEA) used for identification of process equipments failures.
    Results
    Totally 30 failures identified and evaluated using FMEA. P-1 blower's blade breaking and sour gas pressure control valve bearing tight moving had maximum risk Priority number (RPN), P-1 body corrosion and increasing plug lower side angle of reach DEAlevel control valve in tower - 1 were minimum calculated RPN.
    Conclusion
    By providing a reliable documentation system for equipment failures and incidents recording, maintaining of basic information for later safety assessments would be possible. Also, the probability of failures and effects could be minimized by conducting preventive maintenance.
    Keywords: Failure Mode, Effect Analysis (FMEA), Safety, Risk, Natural gas sweetening
  • S. Ahmad*, J. Adl, S. Varmazyar Page 39
    Background And Aims
    Fire and explosion hazards are the first and second of major hazards in process industries, respectively. This study has been done to determine fire and explosion risk severity,radius of exposure and estimating of most probable loss.
    Methods
    In this quantitative study process unit has been selected with affecting parameters on fire and explosion risk. Then, it was analyzed by DOW's fire and explosion index (F&EI). Technical data were obtained from process documents and reports, fire and explosion guideline.After calculating of DOW's index, radius of exposure determined and finally most probable loss was estimated.
    Results
    The results showed an F&EI value of 226 for this process unit.The F&EI was extremely high and unacceptable.Risk severity was categorized in sever class.Radius of exposure and damage factor were calculated 57 meters and 83%,respectively. As well as most probable loss was estimated about 6.7 million dollars.
    Conclusion
    F&EI is a proper technique for risk assessment and loss estimation of fire and explosion in process industries.Also,It is an important index for detecting high risk and low risk areas in an industry. At this technique, all of factors affecting on fire and explosion risk was showed as index that is a base for judgement risk class. Finally, estimated losses could be used as a base of fire and explosion insurance.
    Keywords: Fire, Explosion Index, Process Unit, Risk, Loss
  • A. Joneidi *, A. Talaee, S. Jofee, M. Mehrabaniardakani Page 47
    Background And Aims
    Formaldehyde is one of hazardous compounds that may be found in waste water of different industries. This compound is toxic and biodegradation of it is difficult. The aim of this study is determination of efficiency of isolated microorganisms from polluted effluents by formaldehyde in aerobic and suspended and attached growth.
    Methods
    In this study formaldehyde degrading microorganisms were separated from waste water and soil in a chemical industry. Then microorganisms were isolated and separated by using special culture medias. 12 microorganisms were separated and used for biodegradation of formaldehyde. Standard method was used to evaluated of degradation value.
    Results
    The results showed that pseudomonas aeruginosa was the most effective microorganisms. COD removal efficiency of pseudomonas aeruginosa was 85% in suspended growth and 83% in attached growth condition. Also removal kinetic parameters were calculated That μmax, K, Y, Ks and Kd coefficients were 1.44 l/d, 3.28 mg COD/mg MLSS.day, 0.44 28 mg COD/mg MLSS. day, 1.36 mg/l and 0.04 l/day respectively.
    Conclusion
    Using aerobic conditions in this study to degrade formaldehyde and acceptable output reduction in the COD can be the advantages of aerobic exercises method in comparison with anaerobic exercises.
    Keywords: Formaldehyde, biological degradation, suspended, attached growth, Chemical industries
  • J. Nasl, Saraji*, H. Zeraati, Gr. Pouryaghub, L. Gheibi Page 55
    Background And Aims
    Musculoskeletal Disorders are prevalent in construction workers in comparison to other working groups. These workers in damming construction worked at awkward postures for long times, so ergonomic assessment of jobs was important.
    Methods
    This is a descriptive-analytical cross sectional study that conducted in 2008 on a random sample of workers of damming construction in Takab city (110 men) who were assessed by Nordic Musculoskeletal questionnaire and digital indicator for heart measurement. To estimate Vo2max consumption Fox equation was used and data were analyzed by SPSS software.
    Results
    The average of total time of worked was 36.6 86.8 months. Results showed that the most prevalent (%55.5) MSDs was low back pain which was positively related with type of job, the number of standing and sitting posotions at work, total time of work, age, smoking, level of education, weight,Vo2max that estimated by Fox Equation, and heart rate at working (P<0.05).
    Conclusion
    The results of this study reveal that prevalence rate of musculoskeletal disorders are high among damming construction workers, and heart rate and Vo2max consumption increases with increase in work load. Therefore, optimal physiological conditions should be considered and physical capacity be measured. Prior to employment of workers approperiate corrections are warranted.
    Keywords: damming construction workers, musculoskeletal disorderVo2maxconsumption, heart rate, ergonomic position
  • Seyed, Ali Moussavi, Najarkola*, Sara Karimi, Rajab, Ali Hokmabadi Page 61
    Background And Aims
    Work-related musculoskeletal disorders (WMSDS) is one of the most important problems in working populations of Iranian industries; so, in order to evaluate the integrated roles and effects of various ergonomic risk factors inducing such disorders, the Strain Index (SI) methods was used.
    Methods
    This was a cross-sectional study conducted on 448 male subjects including 63 controls working in administrative jobs and 385 cases working in lathing, welding, melting and foundry jobs using integrated procedure which includes observations, interview, Nordic Musculoskeletal Questionnaire (NMQ) methods and SI model. All workers were questioned. Data were analyzed using SPSS software v. 11 and Excel package.
    Results
    The most prevalent MSDs in upper limbs were found in melting lathing, foundry and welding respectively. There was a significant relationship between age and job groups (c =7.33; df=16; p<0.001). One-way analysis of variance showed a significant differences among means of calculated Strain Indices of administrative (1.06), lathing (6.52), welding (3.68), melting 7.79) and foundry (6.33) jobs (F=5.92; df=16; p=0.005). Also it was revealed that melting job was attributed as "hazardous job" (4 risk level), lathing and foundry jobs were referred to "moderate risk level" (3 risk level), welding job was allocated as "uncertain risk level" (2 risk level), and administrative job was attributed as "safe risk level" (1 risk level). Moreover, there was a significant relationship between DUE and job groups (c2=11.92; df=12; p=0.004).The paired ttest showed significant difference with direct and relatively complete correlation between means of Strain Indices in right (6.53) and left (4.29) hands (r=0.69; t=3.15; p<0.001).
    Conclusion
    The Strain Index (SI) model can be referred as an efficient and applicable method for the assessment of ergonomics risk factors inducing upper extremity musculoskeletal disorders (UEMSDs), classifying jobs, correcting and modifying work situations and preventing DUE musculoskeletal disorders.
    Keywords: Strain Index, SI, Upper Extremity Musculoskeletal Disorders, DUE, Ergonomic risk factors
  • E. Habib *, S.Karimi, A. Hassanzade Page 70
    Background And Aims
    In order to assess specific factors There are several risk assessment methods including occupational repetitive action (OCRA) which is used in industries with repetitive motion, increased force, awkward posture, and lack of recovery periods.These risk factors exists in assembly lines, and the purpose of this investigation is assessment of ergonomic risk factors by OCRA method in assembly lines.
    Methods
    Job analysis was done by observation and each job was degraded to tasks, actions and movements. Nordic standard questionnaire (NMQ) was used for demographic data and upper limbs MSD complaints in 10 factories. Two assembly lines were assessed and 166 OCRA indices were obtained and analyzed with OCRA software and SPSS software using chi square and paired t- test.
    Results
    The results showed that in line B the highest risk in right hand was 66% (low risk), and in line Awas 44% (high risk). In line B the highest risk in left hand was 53.19% (low risk) and in line A was 38% (low risk). The mean value of right and left hand exposure indices was insignificantly different (p<0.001). There was significant relationship between UEMSDs and hand type (p<0.001) and between UEMSDs and age (p<0.001).
    Conclusion
    Line Ahad more risk than line B with respect to repetitive movements. In line A the highest risk was in the right hand whereas in line B highest risk was seen in the left hand. As the most prevalent complaints were in wrists and fingers. We conclude that these parts are more involved upper limbs in assembly line. Finally the OCRA method can be a useful method for evaluation of UEMSDs in repetitive tasks of the assembly industry.
    Keywords: riskfactor, OCRA, Assembly industry, NMQ, UEMSDs
  • I. Alimohammadi*, J. Adl Page 77
    Background And Aims
    Failure Modes and Effects Analysis (FMEA) is a qualitative method for determination of component's fails and study of its effects on machineries. In present study, kilns safety level of two gypsum factories examine.
    Methods
    Production process of gypsum and especially kilns structure studied. FMEAmethod conducted by four steps including determination of analysis insight, information gathering, making of list of kiln's components and filling up the FMEA tables. On the other hand, the effects of fails on production, how to fail, failure rates, severity of fails, and controls of fails considered. Furthermore, the cost of fails and priority of control methods studied.
    Results
    Crack and deformation of shoe plats had highest failure rate in two factories kilns. Some fails such as separation of bricks in kiln of second factory is less than the other one. Meanwhile, some fails including wrapping of kilns trunk, ring corrosion, and fracture of truster's shaft is only present in first kiln.
    Conclusion
    Present study shows that technical features and design of kilns is most important factors in decreasing of failure rates and its cost.
    Keywords: Safety, FMEA, Kiln