An inspection maintenance strategy using the inspection factor

The purpose of this paper is to model an inspection maintenance strategy that is superior to existing strategies and which incorporates the inspection factor.

An appropriate inspection maintenance strategy can help prevent breakdown failure and reduce breakdown and repair costs. However, every inspection also incurs costs. The optimal model for an inspection maintenance strategy would be such that the inspection frequency closely follows the hazard rate of the equipment over its lifetime.

A model with a three‐layered structure needs to be developed. Over time, equipment can be expected to demonstrate a hazard rate that is decreasing, constant or increasing with time. In the first stage a model for inspection frequency is developed that is time‐dependent and can address this requirement. Second, the hazard rate has a dynamic relationship with the inspection frequency, i.e. as the inspection frequency increases, the hazard rate is known to decrease. In the second stage this is incorporated into the model, using the inspection factor. In the last stage a model for costing is superimposed for cost optimization.

The model developed in this paper provides maintenance managers with a powerful practical tool for determining the optimal inspection frequency for equipment over its lifetime.