A simulation model for determining inspection frequency

Frequent inspections of relief valves are necessary to ensure safety. However, inspections are costly and potentially destructive. A delicate balance between safety and cost must be obtained. This is a very complex problem, involving multiple factors that include valve pressure, temperature, medium, age, size and type. This paper presents a simulation model for determining the inspection policy of relief valves in a petrochemical plant, which minimizes the total inspection, repair and risk cost. The model experimented with 17 inspection policies and suggested a new policy, which is expected to reduce the number and cost of inspections by 50%.