Investigating efficiency of permit to work system in the East Azarbaijan Province Gas Company

Abstract

Introduction: In recent years, despite precautions some major incidents occur. One of the procedural methods to safety management is permit to work (PTW) system. A permit to work system is a procedure designed to control non-routine and hazardous works. However, this system by itself does not prevent incidents. This study aims to investigating efficiency of permit to work system in the East Azarbaijan province gas company. Methods: In the present study, which is a cross-sectional study, a set of important indicators influencing PTW system efficiency was extracted and collected by reviewing texts and databases. After evaluating the content validity, the paired comparison questionnaire was completed by experts and priority weights of the indicators were analyzed by an analytic network process and Super Decisions software. In the next step, by attending the East Azarbaijan Gas Company, the efficiency of the PTW system system was evaluated in two stages: document review and field research, using the obtained indicators. In reviewing the documents, the status of completing the five-year permits was evaluated separately according to the type of permit. In the next step, the status of issuing PTW was evaluated in the field and according to the indicators and weight of each, the operations were scored. In statistical analysis, descriptive statistics were used to describe the information and also for data analysis, Friedman test, Pearson correlation (correlation between indicators), one-way ANOVA, independent t-test and linear regression model were used. In the next step, the causes for non-compliance and existing failures were surveyed through interviews with experts and recommendations were presented according to the existing failures. Results: The nine main indicators and 43 sub-indicators influencing the PTW system were ranked. The main indicators from high to low were preventive actions, training, safe procedures, emergency system, control and corrective measures, coordination, monitoring, details of the permit form and documentation, respectively. The highest rate of non-compliance in the documents (completion of permit) was observed in electrical permits, urban areas, summer, afternoon hours and duration of activity 6-10 hours. In the field survey, the average score obtained in all projects was 76.42 %. The highest and lowest scores were assigned to training and preventive actions, respectively, according to the prioritization of the Friedman test. Among the indicators, , there was the most correlation between monitoring and emergency system. Also, according to the results of, efficiency in the categories of type of activity, duration of activity, work experience and education were significantly different. The linear regression also showed that the average score of confined space permits, work activities in the chambers, work in other areas, duration 4-6 hours, work experience over 15 years and bachelor education showed a higher score and also, the R squared of 73% was obtained. In the next step, the causes of deficiencies in the PTW system were classified into three categories: individual, organizational and environmental factors. Conclusion: According to the results, it is recommended that the gas company make improvements to the PTW system, especially with regard to preventive measures. Also, by using the above-mentioned indicators, they can prioritize and perform measures to prevent accidents. Keywords: Permit to Work, Hot Work, Safety, Analitic Network Process