Journal of Occupational Hygiene Engineering
Year:2016 | Volume:3 | Issue:1|Papers Count:8

Introduction: To determine the effectiveness of hearing protective devices that lack technical information is one of the major challenges of occupational health experts to judge the impact of this exposure on reducing the level of occupational exposure to noise.The aim of this study was to design and build a hearing test adapter and experiment it to determine its reduction rate.Methods: Technical information in real environments and glass industries were Hamadan kitchen garden and guards to ensure exceptional performance test results were compared with computational methods.Results: The results of the testing of personal hearing protection compared with the results in real industry environment and octave-band method showed good regressions average operating transmission losses. Results showed that the average noise reduction between measured and calculation method for earmuffs was 9.3, 8.8 dB and 9.3, 11.2 dB for earplugs, respectively. Comparison of the tests, did not show significant differences between the results of the two methods (P>0.05).Conclusions: The results of the designed adaptor for some hearing protectors showed that it is a valid tool for use to reduce rate test of earmuffs and earplugs.

Introduction: A systematic approach is needed for effective coping in an incident. In such a system, preparedness is a top priority. The organization’s readiness depends on factors, including regular exercises. To conduct proper exercise, it is necessary to have a comprehensive scenario. Despite repetitive execution of exercises, there is no commonly accepted template. The present study aimed at selecting the preferred method for developing an emergency exercise.Methods: In the present study, ISO 22398 and HSEEP, as two common patterns were compared through quantifying their usability and chosen by AHP. A panel of crisis experts scored the usability criteria of methods and selected the preferred method.Results: The assessment of usability of both patterns revealed the preference of ISO pattern over the HSEEP pattern. The HSEEP method had better score in learnability and satisfaction, yet the effectiveness, efficiency and total score were higher for ISO 22398.Conclusions: To develop an emergency scenario, it is necessary to follow a suitable pattern. The pattern presented by ISO 22398 is more usable in comparison with the HSEEP pattern.

Introduc tion: In this research Solid Phase Micro Extraction (SPME) for sampling and determination of carbon tetrachloride and chloroform in air was developed and the effect of ambient parameters on SPME was assessed.Methods: For this purpose, a standard chamber was built in the laboratory. The concentrations of compounds in the chamber were measured with SPME. The optimum condition for extraction was determined and compared with 1003 method of national institute occupational safety and health (NIOSH-1003). The samples were analyzed with gas chromatography-mass spectrometry.Results: Carboxen-Polydimethylsiloxane (CAR/PDMS) has high adsorption compared with other fibers and there was no significant difference between sampling rates at different temperatures (range of 20 to 30 °C) and air velocities (2 to 50 cm/s), yet Relative Humidity (RH) had a significant effect on sampling rate. The results showed that samples can be stored in a refrigerator at 4°C for three days. The correlation coefficient of results between SPME and NIOSH-1003 for carbon tetrachloride and chloroform were 0.99 and 0.98, respectively and relative standard deviation of reproducibility between fibers for carbon tetrachloride and chloroform were 13.6 and 12.8, respectively.Conclusions: This study showed that SPME was more sensitive than the NIOSH-1003 method, and was successfully applied for determination of time weight average of carbon tetrachloride and chloroform as a passive method.

Introduction: The workers employed in stone cutting industries are exposed to hand-arm vibration and its complications. The aim of this study was to evaluate exposure to handarm vibration and its health effects on workers in stone cutting workshops.Methods: In this descriptive-analytic study, 40 workers of Hamadan city stone cutting, who worked with stone cutting machines, were examined. Measuring exposure to handarm vibration was performed by standard methods ISO 5349. Symptoms related to handarm vibration syndrome, using a questionnaire, were studied. Data were analyzed using SPSS software.Results: Results showed that eight-hour equivalent acceleration of hand-arm vibration exposure in stone cutting workers exceeded the permissible exposure levels of the country (P<0.05). Highest average hand and arm vibration acceleration was measured in the Z axis. The average vibration acceleration hand-arm and cutting transverse and longitudinal cutting significant difference was observed (P<0.05).Conclusions: In regard to exposure level of stone cutting workers compared with the national exposure limit, the training of health care, non-smoking, and use of anti-vibration gloves, work rotations canthe effective in reducing the risk of health effects. Furthermore, it seems essential to track the health effects associated with human vibration by use of screening tests in the work place seem.

2 Introduction: Musculoskeletal disorders are a major part of occupational diseases in working environments. The aim of this study was to evaluate the risk factors of musculoskeletal disorders by the Muscle Fatigue Assessment (MFA) method. This study also sought to determine the effects of an ergonomic intervention on the mentioned risk in an assembly industry.Methods: This study was conducted on 15 people working in the assembly line. Medical records of assembly line workers were reviewed and Nordic Musculoskeletal Questionnaires (NMQ) after one year of intervention. Activities of these workers in the assembly line were evaluated by the Muscle Fatigue Assessment method (MFA) and workers were given the necessary training. Data were analyzed using the SPSS-16 software.Results: The initial evaluations showed that neck, back, leg and knee, respectively in 6.67, 20 and 13.33% were in "very high" priority corrective measures. Re-assessments after the intervention showed that percentage of people with musculoskeletal disorders in the neck in the "very high" corrective actions changed to zero. The percentage of organs, with "high" corrective actions before the intervention, was greatly reduced. For example, a reduction was recorded around the waist from 60% to 33.33% and neck from 53% to 26.27% after the intervention. A total of 30 cases of abnormalities were detected before the intervention, and after the intervention this number reduced to 11.Conclusions: According to MFA score, risk of musculoskeletal disorders was reduced by intervention in this industry and according to Questionnaire, prevalence of musculoskeletal disorders was also significantly reduced.

Introduction: Musculoskeletal disorders are a major part of occupational diseases in working environments. The aim of this study was to evaluate the risk factors of musculoskeletal disorders by the Muscle Fatigue Assessment (MFA) method. This study also sought to determine the effects of an ergonomic intervention on the mentioned risk in an assembly industry.Methods: This study was conducted on 15 people working in the assembly line. Medical records of assembly line workers were reviewed and Nordic Musculoskeletal Questionnaires (NMQ) after one year of intervention. Activities of these workers in the assembly line were evaluated by the Muscle Fatigue Assessment method (MFA) and workers were given the necessary training. Data were analyzed using the SPSS-16 software.Results: The initial evaluations showed that neck, back, leg and knee, respectively in 6.67, 20 and 13.33% were in"very high" priority corrective measures. Re-assessments after the intervention showed that percentage of people with musculoskeletal disorders in the neck in the"very high" corrective actions changed to zero. The percentage of organs, with "high" corrective actions before the intervention, was greatly reduced. For example, a reduction was recorded around the waist from 60% to 33.33% and neck from 53% to 26.27% after the intervention. A total of 30 cases of abnormalities were detected before the intervention, and after the intervention this number reduced to 11.Conclusions: According to MFA score, risk of musculoskeletal disorders was reduced by intervention in this industry and according to Questionnaire, prevalence of musculoskeletal disorders was also significantly reduced.

Introduction: As a consequence of using fossil fuels, some hazards such as explosion and fire are probable. This study was aimed towards consequence modeling of fire on methane storage tanks in a gas refinery using risk analysis, as well as modeling and evaluating the related consequences.Methods: Hazard analysis by PHA was used to choose the worst case scenario. Then, causes of the scenario were determined by FTA. After that, consequence modeling by the PHAST software was applied for consequence analysis.Results: Based on some criteria, the fire of methane gas tank (V-100) was selected as the worst case scenario at the refinery. The qualitative fault tree showed three factors including mechanical, process, and human failure contributing in gas leakage. The leakage size and weather conditions were effective on the distance of radiation. Using consequence modeling, thermal radiation was considered as the major outcome of the incident. Finally, for outcome evaluation, probit equations were used to quantify losses and the percentage of fatalities due to methane gas leakage and fire occurrence. The maximum number of fatalities caused by fire was obtained as 23 persons.Conclusions: In conclusion, the methane gas vessel in a refinery can be considered as the main center of hazard; therefore, the implementation of safety rules, eliminating mechanical failures, personal protection and education, and effective measures to prevent and fight fire are proposed for decreasing the probable losses and fatalities.

Introduction: One of the recommended methods for evaluating the effectiveness of hearing protection is the use of acoustic fixture, in accordance with the ISO 4869-3 standard. The aim of this study was to evaluate the acoustic performance of fixture for using in noise reduction rate tests of hearing protection devices in the laboratory.Methods: In this cross-sectional study, noise reduction rates of five common ear muffs used in Iranian industries were investigated based on the ISO 11904 standard, microphone in real ear method, using noise dosimeter (SVANTEK, SV102 model), equipped with microphone SV25 model, which was installed inside ear on 30 subjects under laboratory conditions. Furthermore, the noise reduction rate of earmuffs was determined using the AVASINA9402 fixture model in accordance with standard procedures. Data were analyzed using SPSS 21 software.Results: The results showed that the real noise reduction rates of the earmuffs on the studied subjects were from 59% to 94% of nominal reduction rates. Those rates for the ear muffs on the studied fixture were from 64% to 92%. The results showed that the noise reduction rates differences of the ear muffs on subjects compared with those of the ear muffs on fixture were not statistically significant (P>0.05).Conclusions: The results showed that the accuracy of noise reduction rates of earmuffs using fixture compared with real subjects was acceptable. Hence, fixture is a good choice for environments where there is no possibility of acoustic evaluation on real subjects, also for quality control of productions for earmuff manufacturers.