Health Index methodologies for decision-making on asset maintenance and replacement

摘要

Health Index and the Risk Matrix methodology are used to plan maintenance and assist decision-making for service, refurbishment or replacement. Experience has been built up over a number of years and lessons are learned to develop a next generation. The paper discusses the use of the four maintenance styles corrective, periodic, condition based and risk based and how these all are employed in asset management with the tools health index and risk matrix. With periodic maintenance it is discussed how this is optimized for cost rates. For condition based maintenance it is shown how the individual hazard rates for assets are employed, which bears resemblance to the m2M model in TB 422. The health index is related to condition based maintenance. There is discussion about the extent to which it has to be strictly related to hazard rate or also should involve feasible remedial options. A welcome side effect of the health index implementation is that the asset register is checked and improved on the flight. The risk matrix is a tool related to risk based maintenance. The results of the matrix appear sensitive to the group size of assets under consideration. Though often risks are assessed per single asset there are arguments to evaluate groups of assets too. As for a next generation health index methodology two developments are discussed. The first concerns the growing importance of on-line monitoring. Not only will this provide more detailed information, but particularly trends and extrapolation of condition indicator results may provide pre-warning signals that can contribute to much earlier maintenance planning. The second development concerns studies to deal with replacement waves which may also benefit from on-line monitoring.