Journal of Health and Safety at Work

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Introduction: Vehicle engine id one of the main sources of noise which its level is influenced by various parameters. The aim of this study was to investigate the impact of motor oils quality before and after oil change on the variability of vehicle engine induced noise level. In this study it is tried to follow-up the efficacy of motor oil quality on engines sound level.

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Material and Method: First, engine noise of 94 vehicles were recorded for 30 seconds before and after oil change and all the vehicles technical information including mileage, type of motor oil, and type of vehicle were registered. Following, the recorded noises were calibrated in semi-anechoic chamber and the sound pressure levels were measured with A and C-weighting network and main octav bands, using a sound level meters. The obtained results analyzed using SPSS software version 17.

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Results: The effects of motor oil quality on different noise levels of engines were determined and a significant reduction in noise level of vehicles engine was observed. Investigation of the relationship between mileage and motor oil quality on various engines sound level manifested that vehicles with mileage ranged 100000-150000 miles had significant reduction in their sound pressure levels in comparison with other vehicles.

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Conclusion: The results revealed that engine oil is among factors reducing the vehicle engine induced noise level. Moreover, the engine oil type and the vehicle mileage are key variables which determine the impact of engine oil quality on reduction of the sound level of vehicles engine.

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Introduction: 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 Method: 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.

Result: 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.

Conclusion: 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.

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Introduction: Occupational accidents are one of the major challenges of the industrial workplaces. The identifying of the effective causes of the incidents occurrence, could be used to prevent them. This study was aimed to determine basic causes of occupational accidents in a vehicle manufacturing company.
Material and Methods: The occupational accidents leading to loss of time, which cause losing at least one working day, occurred from 2012 to 2017 were analyzed using the Tripod-Beta method and the causes of their occurrences were determined from the active failures to the root causes. The data were analyzed using the SPSS-22 software.
Results: Eighty percent of the occupational accidents that occurred in a vehicle manufacturing company were related to 6 root causes, i.e. the weakness of OR (20%), EC (17%), MM¬ (12%), CO (10%), IG (10%) and DE (9%). Absence of necessary authority to stop working is the most important reason for the occurrence of the weakness of Organization system with a rate of 28%.
Conclusion: By handling three root causes appropriately, i.e. improving OR, EC and MM, more than 50% of accidents can be prevented. Proper hiring of workers, exact definition of accountability and an accurate job description to the employees, proper monitoring and supervision, and near-miss recordings are suggested to reduce this incidence rate.