مجله مهندسی بهداشت حرفه ای
سال یکم شماره 1 (بهار 1393)

Exposure to different chemical compounds such as toluene and ethyl benzene occurs in workplaces، residency، and urban areas. Currently، vehicle cabin environment is one of the new exposure sources of passengers to these compounds. This study aimed to evaluate the effects of in-cabin decoration and deodorizer use on interior concentrations of toluene and ethyl benzene in Logan cars. Samples were collected using activated carbon absorption and low- flow sampling pumps in a roofed parking of 44 “Logan 90” cars and analyzed with gas chromatography along with mass detector. The mean concentration of toluene (42. 02 μg/m3) was higher than ethyl benzene (17. 44 μg/m3) in vehicles. The mean concentrations of toluene and ethyl benzene in cars without decoration were 13. 84 and 11. 24 μg/m3، respectively and in cars with seat cover were 49. 09 and 14. 35 μg/m3، respectively. The results showed that vehicle age had no significant effect on the concentration of these substances; however، non-used vehicles had significantly higher concentrations of these substances. Decoration and deodorizer use had no significant effect on the concentration of toluene and ethyl benzene in cars.

Exposure to high temperatures is common among workers in warm environments leading to some undesirable effects. The aim of this study was to examine physiological responses to heat stress to determine the optimal index for direct measurement of physiological strain in workers of hot environments. In this study, 40 workers of melting and casting process were evaluated. Thermal stress was evaluated based on the WBGT index and physiological strain by measuring oral and tympanic temperature, urine temperature, heart rate, and recovery heart rate. Data was analyzed using SPSS v.16 software. Heat stress exceeded the national and international recommended limits based on the WBGT index in 80% of cases of workstations. The correlations between heat strains including tympanic temperature, oral temperature, urine temperature, heart rate and heart rate recovery to heat stress index were significant, while tympanic temperature had a stronger association according to simple linear regression (P<0.01, R2=0.78). Tympanic temperature had a stronger correlation with the WBGT index among the investigated indices. Accordingly, tympanic temperature could be a useful indicator compared to other parameters for measuring physiological strain in warm workplaces due to the ease of measurement, noninvasive nature, acceptance by workers, and fast and non- interference in the measurement process.

It is not possible to live without using fire. However, fire could destruct human properties in a short time. One of the most important types of fire is intentional fire. This type of fire has become a great problem for insurance companies, fire departments, industries, government and business in the recent years. This study aimed to provide a framework for risk assessment of intentional fires. In the present study, risk assessment and management model for protecting critical properties and security vulnerability assessment model were used to develop a comprehensive framework for risk assessment of intentional fires. The framework was examined in an automotive industry. The designed framework contained five steps as; 1) asset inventory and prioritizing them according to their importance, 2) invasion assessment, 3) vulnerability assessment, 4) risk assessment and design and 5) implementation and evaluating the effectiveness of corrective/preventive actions. Thirty different scenarios for intentional fires were identified by implementing the designed framework in an automotive company, and then the associated risk of each scenario was quantitatively determined. Compared to seven models, the proposed framework represents its comprehension. Development of safety and security standards and a central security information bank to reduce security risks, including the risk of intentional fires is recommended.

In case of inappropriateness of the dimensions of chairs or when users feel pain and pressure in their lumbar region due to poor posture, damage to the spine can be prevented using some additional supports. The aim of this study was ergonomic evaluation of one of these supportive products named “Spine Fit”. In this descriptive and cross-sectional study, in the first stage, five ergonomists evaluated the product regarding its dimension, adjustability, material, conformity, and manufacturer claims. Then, three groups of workers including office workers, office workers with low back pain, and bus drivers filled out a self-administered questionnaire after using Spine Fit. For the first stage, an acceptable adjustability and dimension was found. Conformity for different kinds of office and bus seats was mostly fair. Findings from the second stage revealed that the subjects in three groups were satisfied regarding seats comfort and ease of use. Concerning the conformity of Spine Fit, it was in good level among office workers, while different levels of conformity were observed by drivers of different models of bus. Spine Fit supports back region based on its supportive role in pelvis, lumbar vertebrae column and thoracic spine. Moreover, Spine Fit features that reduce sweating can improve individuals’ convenience.

Exposure of workers to carcinogenic compounds in chemical industries during a long period might cause irreversible health effects. This study evaluated workers exposure to benzene and epichlorohydrin in breathing air in one of the oil-dependent chemical industries of Iran. This descriptive-analytic study was performed in one of the oil-dependent chemical industries of south of Iran, winter, 2012. A total of 173 workers were examined in this study. NIOSH 1501 and 1010 methods were used to assess personal exposure to benzene and epichlorohydrin, correspondingly. Collected samples were analyzed with gas chromatography-mass spectrophotometry method. Among 346 collected samples, benzene was identified in all cases (100%) and epichlorohydrin in 156 samples (45%). A significant difference was found in the mean of exposure to benzene and epichlorohydrin in various workshops (Pvalue <0.05). Occupational exposure to benzene in machiner with 1.68 ppm and patrol officers with 0.018 ppm were the highest and lowest values, respectively. There was no significant difference in the mean exposure to benzene in various occupations (Pvalue > 0.05). It seems that work nature of employees in chemical industry affects their exposure to volatile organic compounds in workplace. According to the results, due to the proximity of compounds concentration to the action level, especially benzene and also the workers exposure to less than the maximum limit in the long-term, reducing exposure through appropriate control measures are necessary.

Comfort lighting is one of the most important topics, which provides optimum physical conditions in general environment and workplaces such as hospitals. This study aimed to evaluate general, local and area artificial illumination of Hamadan city hospitals. In this descriptive-analytical study, general, local and area artificial illumination in seven Hamadan hospitals in 2006 were evaluated. Lighting intensities (illuminance) were measured according to recommended IESNA method using the lux meter model (Lutron-Lx102) in the early hours of night. Lighting quality parameters such as color rendering, technical suitability of design and lighting uniformity were evaluated. Data was analyzed using SPSS 13. The average of interior illuminance was 90.44 ± 46.97 lx, which was lower than the national recommended limits. Maximum and minimum intensity values of interior illuminance were in nursing station and laboratory, respectively. The average of area illuminance was 47.92 ± 53.2 lx and local illuminance was 131.5 ± 60.2 lx, which were lower than the recommended limits. Maximum intensity of local illuminance was in laboratories and the minimum levels were in admitted rooms, checkup and injection units. In total, 90.6% of general interior lighting systems, 83.3% of area lighting systems and 100% of local lighting systems had unaccepted design. The average of general, local and area illuminance in Hamadan hospitals were not within the acceptable limits for comfort lighting. To obtain comfort lighting in studied hospitals, reforming and modifying lightening systems is necessary.

Educational and research laboratories in universities have a high risk of fire, because they have a variety of materials and equipment. The aim of this study was to provide a technical plan for safety improvement in educational and research laboratories of a university based on the design of automatic detection, alarm, and extinguishing systems. In this study, fire risk assessment was performed based on the standard of Military Risk Assessment method (MIL-STD-882). For all laboratories, detection and fire alarm systems and optimal fixed fire extinguishing systems were designed. Maximum and minimum risks of fire were in chemical water and wastewater (81.2%) and physical agents (62.5%) laboratories, respectively. For studied laboratories, we designed fire detection systems based on heat and smoke detectors. Also in these places, fire-extinguishing systems based on CO2 were designed. Due to high risk of fire in studied laboratories, the best control method for fire prevention and protection based on special features of these laboratories is using automatic detection, warning and fire extinguishing systems using CO2.

According to previous researches, worker's participation in issues affecting their working condition is the key to success in ergonomics interventions in working environments. Therefore, the present study was performed to increase active particapitation of supervisors in production line and also to identify and assess ergonomics risks and presenting modification actions (Kaizen) by themselves in Pars Khodro automobile manufacturing company. A manual regarding lifting objects and body postures, according to the Finish evaluation method, was provided for supervisors in production line and related trainings were presented to them. Then, they were asked to insert the results of their assessments and suggestions in special forms during one year. The presented assessments and suggestions were examined by ergonomics experts. According to the assessments conducted by supervisors, 26 work stations had high ergonomics risks, 51 had ergonomics risks with an average level, and 45 had low ergonomics risks. Moreover, the number of required Kaizens presented by supervisors was increased from 18 cases in the first year to 42 cases in the second year, after implementation of ergonomics training and identifying and assessing ergonomic risks by supervisors. Empowering and training supervisors increased worker's participation. In case of adequate training, supervisors can present practical solutions to reduce ergonomics risks in their workstations.