其他摘要:Background and Aims Permit to work (PTW) system as an operational control methods, is an accepted system for control of maintenance activities hazards in chemical industries. The main objective of this study was degree of conformity analysis between existing situation of PTW system and audit criteria. Methods In this cross - sectional study, PTW system was audited in an oil and gas extracting industry by checklist. Results Major nonconformities include outdating of system legal and regulation, non existence of permit for majority of dangerous activities, unidentified training needs, incomplete identification and risk assessment of maintenance hazards before doing them, unspecified inspection and survey frequencies during works and nonexistence of scheduled auditing for the system. Conclusion PTW audit results showed that there is a noticeable gap between audit criteria and audit evidences. So that the examined system had nonconformities in all of the checklist sections system, training and competency, permit, coordination and monitoring.