Planned or scheduled maintenance, embraces three orms of maintenance: breakdown, preventive, and predictive. Like other TPM activities, building a planned-maintenance system should done systematically, one step at a time. The purpose of performing predictive and preventive maintenance is to eliminate breakdown, but even when systematic maintenance practices are carried out, unexpected failures still occur. Such failures reveal inadequacies in the timing and content of maintenance plans and highlight ineffective recurrence-prevention measures. In TPM, planned maintenance activities emphasize monitoring mean times between farlures (MTBF) and using that analysis to specify the intervals for tasks in annual, monthly, and weekly maintenance calendars.
A classic example of planned maintenance activity is shutdown maintenance. To make them more effective, companies are preparing for shutdowns earlier and earlier. Their goal is to lay out reliable plans before the job begins. Because the tasks performed during shutdown maintenance follow a set pattern, it is helpful to base the work plan on a work breakdown structure (WB5) . This diagram facilitates accurate estimation of the tasks to be performed during shutdown maintenance, along with their sizes. It can be used to gauge the staff and materials needed for the job and to monitor the budget and the achievement of the objectives.