Journal of Health and Safety at Work

Introduction: Application of inherently safety principle in the early phase of the design process is very efficient, as this approach is an economic and high efficiency method. While a complete information is not available in the initial phases of the process, the use of valid index to evaluate inherently safety can be efficient. In this case, the best route to design safer process can be selected by comparing the quantitative results.

Material and Method: The comprehensive index to evaluate the inherently safety design (ISD) and cost evaluation of the implementing inherently safety design (ISDC) were studied using a three-step hierarchical matrix screening in this research. Utilizing the proposed inherently safety index, Acetic acid production process and cost resulting from ISD were evaluated. Dimensions of the Matrix for ISD and ISDC included: 1) quadrature inherently safety design vector, 2) location vector of inherently safety design and 3) quantity parameter vector of inherently safety design.

Result: In order to optimize the implementation of inherently safety design and its cost, three hypotheses were used. From them, the idea of using two processes with half capacity and also using 50% Methanol were selected as a design with the highest level of inherently safety and a design with the lowest-cost process, respectively.

Conclusion: In these evalustions the total score for the assumptions of the inherently safety index 1, 2 and 3, were 55,70 and 135, respectively. And the total cost assumptions 1, 2 and 3, have been estimated 858,000, 746,000 and 803,000 US dollars, respectively. Therefore, this tool could show the impact of various scenarios in inherently safety design and also the contrast between the four principles of ISD and its impact on safety and cost factors can be analyzed using an alternative system supplier of methanol.

Introduction: Examining the effect of bus drivers’ demographic characteristics as well as workplace conditions on their traffic behavior and performance is important not only for drivers’ health and safety, but also for the safety of bus passengers. The aim of this study was to investigate the relationship between demographic variables and work shift schedule on the behaviors pertaining to “hazard monitoring”, “relax driving”, “fatigue proneness”, and “thrill seeking” among intercity bus drivers.

Material and Method: In this cross-sectional study a sample of 321 bus drivers were randomly selected from Tehran intercity bus terminals. The BDRI questionnaire was used to collect data. The Pearson’s correlation coefficient and the ANOVA and Tukey’s HSD tests were used to analyze the data.

Result: In general, the findings showed that age, driving experience and rest time period positively correlate to lower fatigue, lower thrill seeking and more relaxed driving. Drivers with higher vehicle age were found to perform worse than others in hazard monitoring and to be more prone to the stress and fatigue. Also, fatigue and relaxed driving were significantly related to the marital status and cigarette usage. In addition, drivers who were college graduate or above were found to perform worse than other drivers considering all of the four factors. Furthermore, those who drive in mountainous routes were found to perform worse than other drivers in hazard monitoring and fatigue proneness.

Conclusion: Since the age and driving experience were found to influence fatigue proneness, hazard monitoring and relaxed driving, thus, setting up specific training courses for different driver age groups aiming to enhance their awareness concerning on managing these factors might help drivers improve their performance in these factors. Furthermore, regarding the effect of rest period and route type on the drivers’ fatigue and hazard monitoring ability, appropriate regulations are needed to mitigate the effect of these factors on the performance of drivers.