Economic Evaluation Techniques for Inspection/Repair/Replacement Decisions on Plant Components

Many critical industrial plant components are in the aging part of their life cycle. This is because many of the US plants were built during the 50's and 60's. In the aging portion of component life the failure rate is exponential. This creates a need for predictive maintenance expenditures to maintain reliability.

The primary challenge in predictive maintenance is ranking and timing of which component/s to inspect, repair or replace. This discussion is about a model which produces a prioritized list of critical components.

The objective is to maximize the return on the invested maintenance dollar. Net Present Value (NPV), as a decision making criterion, is a way of achieving this "Value Added," objective. NPV also accounts for the cash flow of consequences over the service life of equipment. Maintenance expenditures are investments made in order to receive the benefit/s of production return in the near, intermediate and long term.