مجله بهداشت و ایمنی کار
سال ششم شماره 2 (تابستان 1395)

Safe driving requires the ability of the driver to receive the messages and complying with them. The most significant consequences of noise pollution are on the human auditory system. Disorders in the auditory system can have harmful side effects for human health. By reducing this kind of pollution in large cities, the quality of life, which is one of the biggest goals of the governments, can be considerably increased. Hence, in the present research, some parameters of vehicle tires were examined as a source of noise pollution, and the results can be taken into consideration in noise pollution reduction.
Material and Several vehicles with different tire width were selected for measuring sound level. The sound levels were measured for moving vehicles with the use of the Statistical Pass By Method (SPB, ISO 11819-1). Following sound level measurements for moving vehicles and by considering tire width, mathematical model of noise level was predicted on the basis of the obtained information and by usage of SPSS program and considering vehicle tire parameters.
The result of this study showed that the vehicle speed and tire width can affect different sound levels emitted by moving tire on road surface. The average speed of vehicles can play an important role in the noise pollution. By increasing speed, rotation of the the tires on the asphalt is increased, as it is a known factors for noise pollution. Moreover, changing the speed of vehicles is accompanied with abnormal sounds of vehicle engine. According to regression model analysis, the obtained value of R2 for the model is 0.8367 which represents the coefficient of determination.
The results suggest the main role of the vehicle speed and tire width in increasing the noise reaches to the drivers and consequent noise pollution, which demonstrates the necessity for noise control measures. According to the obtained model, it is understood that changes in noise levels and tire width are more than those of vehicles speed. The coefficient of 0.1482 for tire width, comparing to coefficient of 0.1195, shows that considering the proper tire width can be effecttive in reduction of sound level.

Although human industrial activities are as a part of efforts to achieve greater prosperity, the risks related to these activities are also expanding. Hazard identification and risk assessment in the oil and gas industries are essential to reduce the frequency and severity of accidents and minimize damage to people and property before their occurrence. The aim of this study was to evaluate the liquefied and pressurized petroleum gas spherical tanks in a refinery and assessing the risks of Boiling Liquid Expanding Vapor Explosion (BLEVE) phenomenon.
Material and In this study, the risks of BLEVE phenomenon were assessed, using the Bowtie method. The consequences of explosion wave phenomenon and the resulting wave quantity and its impacts on the neighboring machineries and equipment were analyzed. PHAST software version 6.54 has been used for modeling the BLEVE phenomenon.
In this evaluation, generally five causes and two consequences were identified for BLEVE phenomenon. In order to reduce its consequences, forty-three controlling measures were introduced to prevent the BLEVE phenomenon and the impacts of 31 control measures were identified. According to the conducted analysis, it was found that the spherical tank blast wave caused by LPG can lead to explosion of close located tanks which can create a chain of explosions.
The results of modeling and risk assessment can be used to identify the BLEVE phenomenon causes and its effects on nearby people and equipment. Based on these results, preventive controlling measures can be implemented and also be determined by adopting proper design and layout, margin of safety for personnel, equipment and accessories.

Volatile organic compounds from industrial activities are one of the most important pollutants released into the air and have adverse effects on human and environment. Therefore, they should be removed before releasing into atmosphere. The aim of the study was to evaluate xylene removal from air by nano-grapheme and nano-graphene oxide in comparison with activated carbon adsorbent.
Material and After preparing adsorbents of activated carbon, nano-graphene, and nano-graphene oxide, experiments adsorption capacity in static mode (Batch) were carried out in a glass vial. Some variables including contact time, the amount of adsorbent, the concentration of xylene, and the temperature were studied. Langmuir absorption isotherms were used in order to study the adsorption capacity of xylene on adsorbents. Moreover, sample analysis was done by gas chromatography with Flame Ionization Detector (GC-FID).
The adsorption capacities of activated carbon, nano-graphene oxide and nano-graphene for removal of xylene were obtained 349.8, 14.5, and 490 mg/g, respectively. The results of Scanning Electron Microscope (SEM) for nano-graphene and nano-graphene oxide showed particle size of less than 100 nm. While, the results of Transmission Electron Microscope (TEM) showed particle size of 45nm for nano-graphene and 65 nm for nano-graphene oxide. Also, X-Ray Diffraction (XRD) showed cube structure of nano-adsorbents.
In constant humidity, increase in exposure time and temperature caused an increase in the adsorption capacity. The results revealed greater adsorption capacity of xylene removal for nano-graphene compared to the activated carbon, and nano-graphene oxide.

Workplace design is one of the factors that can influence comfort, performance, productivity and the health status of employees. The effects of this factor on human’s productivity and performance are studied in the domain of ergonomics. The impact of workplace design on workers’ productivity and performance can be determined by investigation of the quality of the design. The main purpose of the present study was to investigate the influence of workplace design on productivity of the bank clerks.
Material and Samples in this cross-sectional study were comprised of 150 employees of 22 different branches of a bank in Tehran city. Data collection tools included demographic questionnaire and a questionnaire related to the effects of workplace design on employees’ productivity, developed by Hameed and colleagues. Correlation and regression statistical tests were used in order to analyze data.
According to the results, the mean (±SD) for age and job tenure of participants were 37.2(±6) and 13(±7) years, respectively. Of the surveyed demographic features, a significant relationship was observed between age and scores belonging to the temperature and furniture (P-value Overall, appropriate and high quality design of work environment can improve productivity of bank clerks. In other words, employees’ productivity can be enhanced by comfortable and ergonomic design of working environment and also by considering their needs.

Adherence to the design values and ventilation standards (VS) after installing and also maintaining continuous work of ventilation system with maximum performance throughout its life are amongst the reasons of ventilation systems monitoring. Therefore, the aim of this study was to evaluate performance of local exhaust ventilation system for control of dust by measuring the operating parameters and also to compare it with ventilation standards (VS) and design values.
Material and The present research is a descriptive and cross-sectional study, conducted in three sections of measuring, monitoring and evaluating the operating parameters on hoods, channels and fan of ventilation system based on the current status of the system, documentation (design), and recommended standards (VS). Static pressure, velocity pressure, surface area, and flow rate were measured based on the recommendations of various sources and ACGIH industrial ventilation manual, and the data were compared with the design and recommended values, using the SPSS software version 16.
The results of paired sample t-test between flow rate and velocities of design and current status, showed significant differences in various parts. Accordingly, the results revealed a reduction of more than 50% in the design duct velocity compared to the current duct velocity, while design duct velocity is 1.3 more than the standard duct velocity of current status, and current duct velocity is about 65% of standard duct velocity.
The reduction and nonconformity of the results of measurements of operating parameters (after a minimum of two decades) with design and standard values are corroborant and sufficient reason for obstructions, abrasions, leaks, imbalance of system ducts and their inefficiency in some branches. Since there is no base line measurements for system (supposing that the system worked with maximum amounts of setup time), one of the reasons for these changes can be attributed to lack of schedule for regular and appropriate maintenance.

High level of workload and its consequent cognitive failures are among factors which impact nurses’ behavior, performance, and efficiency. This study aimed to investigate the relationship between nurses’ cognitive failures and perceived workload.
Material and This cross-sectional and descriptive-analytical study was carried out among 150 male and female nurses, working in different units of Emam Khomeini and Vali-e-Asr hospitals in Tehran in 2013. NASA task load index (NASA-TlX) and Cognitive Failure Questionnaire (CFQ) were used to assess workload and cognitive failures, respectively. Data were analyzed using Pearson Correlation, Independent sample t-test, and one-way ANOVA statistical tests with SPSS software version 20.
Pearson and Spearman correlation coefficients test results showed a significant relationship between nurses’ mental workload and their memory for names (P-value The results showed a high level of workload among study nurses. Furthermore, the relationships between some dimensions of mental workload and cognitive failures were confirmed, so that an increase in workload dimension can lead to more cognitive failures while doing task.

Safety climate is the perception of personnel about the priority of safety in an organization. The objective of this study was to evaluate safety climate using Nordic questionnaire in a hospital.
Material and In this cross-sectional study, 92 nurses working in different wards of a hospital in uromia city, Iran, filled out the NOSACQ-50 questionnaire. The responses of nurses were recorded with a 4-point Likert scale. The results were analyzed using descriptive and analytical statistics.
Seventy-two percent of nurses were female and the remainders (28%) were men. The mean score of safety climate dimensions was different. “Management safety priority, commitment, and competence” and “Safety communication, learning, and trust in co-workers safety competence” dimensions obtained the lowest and the highest scores by nurses, respectively. The mean score of safety climate ranged 2.49 to 2.67 in different wards of the hospital. What is more, the mean safety climate was not statistically differed among nurses of various age and work experience categories (P-value> 0.05).
According to the results, it can be noted that the level of safety climate in the hospital was fairly good from the nurses’ viewpoint. However, attempts should be made to improve it, especially in the safety management related dimensions. Corrective control measures should be implemented in all wards of the hospital for all personnel with any age and work experience.

Requiring industries for implementing industrial waste management programs and planning for proper waste disposal is essential in order to achieve sustainable development. Therefore, industrial waste management program was done in Kavir Steel Complex, in Aran va Bidgol region to identify and classify industrial waste and also to present solutions for improving waste management. In this complex, production process is hot rolling steel and the product is rebar.
Material and The preset study was conducted in Kavir Steel Complex. Following survey of production process and sources of waste, the type and volume of produced waste were identified and measured during 3 months. Then, the classification of wastes was done according to the Bazel Convention and Resource Conservation and Recovery Act (RCRA), and finally new industrial & health solid waste management program was presented.
Considering the volume, industrial waste of production process in Kavir Steel Complex was between 130 to 180 grams per each ton of rebar. Main industrial waste included oxide of steel billet, industrial sludge, used oil and lubricant which were classified according to the RCRA: 8 materials with T code, 1 with C code, 5 with I code and 3 materials with C code.
The results revealed that the most amount of industrial waste in Kavir Steel Complex is the waste of steel billet and industrial sludge, and more than 90% of Kavir steel industrial waste were reused and recycled inside or outside of this complex. It is recommended that used oil to be transport and maintain in the safe containers.