Journal of Health and Safety at Work

Introduction: By industrialization, work-related accidents emerged as one of the most threatening factors of human life therefore analyzing the causes of accidents and providing control measures to prevent reoccurrence of similar accidents are of crucial importance.
 

Method and Materials: This is an analytical-descriptive study in which the collected data were analyzed using Ishikawa and SCAT methods and results related to the relationships between variables were examined. In this sense, first, accidents leading to amputations associated with operating with press machines (stuck between two objects) were analyzed by Ishikawa method and the obtained causes were classified into three groups: direct causes, interface causes, and root causes. Then, the obtained causes and the control measures were placed in SCAT table. The effect of causes of accidents and their ranking were determined using Chi-Square Test and Friedman's test, respectively. Accordingly, appropriate control measures were provided based on the accidents causes.
 

Results: The most significant interface causes is hurry at work the most significant root causes is inappropriate and ineffective supervision and the most important control measures is establishing effective HSE management system in the organization.
 

Conclusion: According to results, the main interfce causes of accidents leading to amputation due to operating with press machines is hurry at work because of increased production volume particularly by contractor companies. Furthermore, non-dynamic HSE system accompanied by ineffective supervision of personnel’s unsafe acts by the first layers of management are recognized as the basic causes of such accidents.

Introduction: Leakage from process equipment and the entrance of flammable fluids to surrounding atmosphere may cause flammable gas cloud. The coincidence of flammable gas cloud with ignition source could make flash fire or vapor cloud explosion that cause injury and fatality. The concept of reduction of confluence of flammable gas cloud and potential sources of ignition is known as hazardous area classification. Several standards have provided methods regarding hazardous area classification; however, of the disadvantages of them are lack of an accurate determination of hazardous areas due to potential leakage sources which is because of low flexibility in process condition variation and equipment layout and also not considering effect of weather conditions and cumulative effects of release sources.
 

Method: In this paper, risk-based hazardous area classification is optimized using parameters such as the number of influencing release sources and weather condition probabilities. In this method, the determining factor of hazardous area boundary is the probability of acceptable ignition for every specific location. This probability is calculated using quantitative risk assessment with PHAST RISK software version 6.7 on the gas boosting unit of a gas refinery as a case study.
 

Result: The results of this method showed the full dependency of hazardous area boundary to cumulative effects of potential sources of release and the prevailing wind direction and it also demonstrated that the suggested optimized method can consider wind direction probabilities and cumulative effects of potential sources of release in risk-based hazardous area classification calculation.
 

Conclusion: Comparing the results of this method with the usual method determines that this method has some advantages such as considering all sources of release and cumulative sources of release and considering wind direction probabilities in determining boundary of zone 2 which makes the hazardous area classification very precise and flexible.