pISSN: 2008-5109
eISSN: 2008-5435
Editor-in-Chief:
Mohammadreza Monazzam Esmaeilpour, PhD.
Vol 6 No 4 (2014)
Published:
2015-10-22
Articles
-
The purpose of this study was to assess exposure to hand-arm vibration in tiller users, Forty users of tiller in northeastern provinces of Iran were examined to measure hand-arm vibration parameters such as root mean square acceleration (RMS), total equivalent acceleration, Vibration Dose Value (VDV) and crest factor in three directions (x, y, and z) and various operating modes for comparing them with the relevant permitted standard levels. The hand-arm vibration measurement was done according to the standards ISO 5349-1 and ISO 5349-2. The obtained results indicated that the exposure level in three modes of rota-tilling, transportation and idling were equal to 16.95, 14.16 and 8.65 m/s2, respectively. In all measurement modes, the exposure to vibration in the direction x was greater than that of y and z. Moreover, the average crest factor was calculated less than six. The highest vibration dose values were measured in rota-tilling mode when the tiller was in 2nd gear (60.76 m/s1.75) and 1st gear (56.83 m/s1.75). The results indicated that the permitted working time was only few seconds and there was a risk of musculoskeletal disorders. The present study emphasizes on the need for interventional and control managerial measures to eliminate or reduce hand-arm vibration transmitted to the tiller users' hands for avoiding major problems such as musculoskeletal disorders, discomfort and premature fatigue. In this regard, further studies are required to identify vibration sources in different types of tillers.
-
Release Volatile organic compounds (VOCs) as environmental and occupational pollutant cause macro perspective affect such as climate change, humans and economic consequences. Although fixed bed absorber is widely used as a controlling method because of its economically and availability, but these absorbers are facing some issue like high pressure drop, non-uniform distribution of fluid, channeling and blocking. Fixed and fluidized beds adsorbent was compared from three economic, environmental and engineering perspectives using Multi Criteria Decision Making analysis (MCDA) technique. An annular fluidized bed adsorber was designed and charged with 50-100 µm (100-140 ASTM mesh) activated carbon (AC) particles. Effects of factors like flow rate, particle size, inlet concentration and adsorption capacity of VOCs was investigated under steady state. In the flow rate less than 0.25(Lit.min-1), inlet gas slowly passes through the void spaces of the bed’s particles. By increasing the inlet flow from 0.3(Lit/min-1), bubbles start to form in the bed and the bed pressure drop decrease. The pressure drop of 6 (g) of AC in minimum fluidization velocity was 20(KN.m-2). However, the pressure drop of 10 and 20(g) of AC were 150 and 420(KN.m-2) respectively. “maximin” technique used for comparison of two beds indicated that minimum score of pack bed absorber are 0.37 while the minimum score of fluidized bed adsorber are 0.5. It indicated when the adsorbent particles are smaller, fluidized bed adsorber are more suitable to use. In addition, using MCDA technique indicated that annular fluidized bed adsorber could considered as an alternative of fixed beds adsorber.
-
This study was focused on measuring air pollutants emission from factories producing the asphalt related products in Delijan Industrial Estate, which is the main center of asphalt related products in Iran. Emissions of four factories were analyzed for air pollutants using a stack analyzer, Testo 360, Testo Co., and Germany. The average concentration of all measured stacks for PM, THC, CO, NOx, SO2, and CO2 was 698.0, 195.4, 109.3,and 30.7, 15.1 mg/m3 and 5.17%, respectively. Estimation of the emission rate for the studied factories with total annual production of 46,500 tons of shingles and rolling asphalt revealed the annual emissions of 32.9, 8.9,5.0, 1.4, 1.1, and 4,423.4 tons/yr for PM, THC, CO, NOx, SO2, and CO2 respectively. It was also shown 435.4,118.2, 66.7, 189.4, 14.1, and 58,503.1 tons/yr for those pollutants by all factories in Delijan Industrial Estate with annual production of 615,000 tons. The emission factors for the above-mentioned pollutants were 708.1,192.2, 108.4, 30.8, 22.9, and 95,127 g/ton respectively. Comparing the results with national standard showed that, the PM emission concentration was 2 times greater than Iranian emission standard (250 mg/m3) and its emission factor exceeded the USEPA emission factor. The rest of pollutants concentrations and emission factors were in the range of both standards. In conclusion, all studied factories need to reduce their particle emission using appropriate air cleaners.
-
Heat stress effects on physical and mental health of workers and decreases human function. Asphalt workers are both exposed to the heat of their working process and to the sun heat. This study aimed at evaluating thermal stress and its following function fall and the effect of asphalt work on the degree of heat stress and asphalt workers’ physiological parameters. The present study was done at the work location of 29 asphalt workers in Qum City, central Iran. The degree of thermal stress was by WBGT index. The workers’ physiological parameters such as their blood pressure and pulse rate were studied as well. In order to determine the function fall caused by thermal stress, the related graph was utilized, and the calculated data were analyzed by SPSS software. The longest heat (WBGT) exposure period of asphalt paver drivers, troweling workers, shoveling workers, and burner service workers were 31.59, 32.68, and 33.53 centigrade degrees, respectively causing the laborers’ function fall by 70, 85, and 82%. Increase in WBGT is followed by increase in the average diastolic and systolic blood pressure and pulse rate. There was found a significant relationship between WBGT in the asphalt working locations and out of asphalt working locations (P<0.05). In addition to diseases and effects caused by thermal stress, it is a major reason for man’s function fall and efficiency decline, which eventually causes poor production. Thus, accurate planning and controlling thermal stress are required to prevent occupational diseases and improve human function.
-
Nowadays, using public transportation vehicles like metro in large cities are of significance, and exposure to whole-body vibration for the metro passengers is one of the physical contaminations. This paper is conducted with the aim of evaluating the passengers’ convenience and health both in sitting and standing conditions. The present study was done on the passengers of lines 1, 2, and 4 of Tehran metro with the use of an oscillator and a SVAN958 analyzer of SVSNTEK Co., based on the measurement methods and guidelines of ISO 2631-1, 4. The average amounts of RMS acceleration while sitting was 1.1 m/s2 with the standard deviation of 0.14 and while standing was 0.91 m/s2 with the standard deviation of 0.05; estimated VDV amount while sitting and standing equaled 6.72 m/s2 with the standard deviation of 1.26 and 6.48 m/s1.75 with the standard deviation of 0.96. Calculated RMS amounts generally fluctuated between level 3 (fairly unpleasant) and level 4 (unpleasant) of convenience evaluation scale, and total calculated VDV amounts for the sitting passengers was 1.1 m/s1.75 , being more than the perceived dose of standing passengers.
-
Safety performance is the overall performance of the organization safety management system in the operational system of safety. In the present study, the components of safety performance included visible management leadership, employee participation, training, inspection, implementation tools, and maintenance. The objectives of this study were to assess safety performance, and to analyze difference in safety performance components in the metal products industry in Iran. The target population included managers and non-managers and the random sampling method is used. A total of 714 respondents participated in present study. The method applied in present study was a questionnaires quantitative type based on a Lickert scale and the data collected were analyzed statistically. The one-way ANOVA was applied to assess significant differences in safety performance components in the metal products industry. The results indicated that safety performance was not strong based on the mean for average score of 2.61 which was less than 3 compared to the possible maximum of 5. The one- way ANOVA analysis showed that there was a significant difference among safety performance components where respondents regards maintenance as a stronger component while employee participation as the weakest. The result of study also revealed that to improve safety performance in the metal products industry, all components should be improved.
-
One of the fundamental needs for the human is to have a workplace in which they can do their workappropriately. Worldwide energy crisis necessitated the construction of official buildings with smaller space and less air ventilation. This led to the reduction in air conditioning, accumulation of the contaminants in indoor, increased exposure, health threat concerning the staff in official environments. One of these problems is Sick Building Syndrome (SBS). The focus of this study was to observe the effect of SBS on the productivity of the staff. In addition, the work related effects of psychological and mental symptoms on the productivity were studied separately. This cross-sectional study was carried out on 105 staffs of an official building. In this study to observe the SBS a combination of questionnaires from the UK Health and Safety Organization and ESCO studies were used, and to survey the productivity, Hersey Blanchard model was utilized. To analyze the data Paired t-test, Tukey methods were used. This study shows that there is not a significant relation between the SBS and the productivity factor (P=0.061), not a significant relation between anxiety and distress (P=0.550) anger (P=0.287) forgetfulness (P=0.091) lack of sleep (P=0.323) and productivity. However the study shows a meaningful difference between irritability (P=0.034) distress (P=0.011) mental fatigue (P=0.029) and productivity. The mental SBS symptoms have impact on productivity. However more researches need to be done about the direct relation between SBS and the productivity level of staff.
-
Tire manufacturing industry has a history of more than half a century in Iran, where 14 thousand workers are employed. The old and semi-automated processes equipment, backward technology, and raw materials impurity lead to significant exposures to occupational carcinogens such as benzene. This study was to assessment of benzene exposures and evaluation the resulting cancer risk in two tire-manufacturing factories. One hundred workers in two target tire-manufacturing factories selected as ―exposed group‖. Personal monitoring was conducted in all process units according to NIOSH 1501 method. Inhalation health risk of benzene exposure was estimated via two assessment models. Data were analyzed using SPSS and quantitative values were reported as Mean ± Standard Error. Occupational exposure to benzene in 68 percent of workers has exceeded the current exposure limit. The highest level of benzene (5.06 ppm) found in cement making unit. The odds ratio of leukemia was 2.06 times the working population without benzene exposure, as well; the cancer incidence was 16.14 cases per 1000 workers. This study as screening approach is first on addressing the risk assessment of Iranian tire manufacturing workers. The levels of personal exposures and cancer risk were unacceptable and this may provide a basis for developing the control measures in future.
