A management study of pressure relief valves

As a safety concern, pressure relief valves play important roles in protecting a pressure vessel or pressurized system. The conditions of the pressure relief valves deteriorate day after day which depend on the operating conditions of process train such as variation of pressure and temperature, containment and frequency of relieving during operation. If the deteriorative relief valves failure to operate normally as required, a catastrophic event may occur while no other protective means provided. So, to prepare a plan of inspection and maintenance with suitable intervals based on the knowledge of the relations between the conditions of pressure relief valves and plant operation parameters, is a safety strategy to plant owner. With practical inspection and maintenance works of pressure relief valves performed in a process train, this paper collects the as-received pressure relief valves test results from current inspection intervals and presents the relationships between as-received test data and operation parameters based on analysis of variation (ANOVA) and analysis of correlation. With these analyses, one can get the relationships between the decay conditions of the pressure relieve valves and their operating parameters. A site survey of as-received test results will be used as a case study and the weighting factors corresponding to the operation parameters are also presented.