Prototype modelling of irregular condition monitoring of production plant

The previously reported modelling of inspection-maintenance problems utilizing the delay-time concept is here extended to embrace condition-monitoring checks. The main requirements are the relaxation of regular periodic inspections, and the requirement that the initial point of a defect be measured as the time from the as-new condition and not, as previously, as the time since a previous inspection. An expression for the probability of a defect arising as a breakdown and as an inspection repair is constructed for a general inspection policy, under the assumption of both perfect and imperfect repair. The revised role of these probability expressions in modelling the process of maintenance for cost-effective production is discussed, various modelling alternatives are outlined, and a numerical example is presented. Parallels are drawn between condition monitoring in an industrial setting and in the delivery of health care.