Maintenance scheduling is the process by which jobs are matched with resources (crafts) and sequenced to be executed at certain points in time. The maintenance schedule can be prepared in three levels depending on the horizon of the schedule. The levels are: (1) medium range or master schedule to cover a period of 3 months to 1 year; (2) weekly schedule, it is the maintenance work that covers a week; and
(3) the daily schedule covering the work to be completed each day.
Figure 11.4. An example of a maintenance planning sheet
The medium range schedule is based on existing maintenance work orders including blanket work orders, backlog, preventive maintenance, and anticipated emergency maintenance. It should balance long term demand for maintenance work with available manpower. Based on the long-term schedule, requirements for spare parts and material could be identified and ordered in advance. The long- range schedule is usually subjected to revisions and updating to reflect changes in plans and realized maintenance work.
The weekly maintenance schedule is generated from the medium range schedule and takes account of current operations schedules and economic consideration. The weekly schedule should allow for about 10–15% of the workforce to be available for emergency work. The planner should provide the schedule for the current week and the following one, taking into consideration the available backlog. The work orders that are scheduled for the current week are sequenced based on priority. Critical path analysis and integer programming are techniques that can be used to generate a schedule. In most small and medium sized companies, scheduling is performed based on heuristic rules and experience.
The daily schedule is generated from the weekly schedule and is usually prepared the day before. This schedule is frequently interrupted to perform emergency maintenance. The established priorities are used to schedule the jobs. In some organizations the schedule is handed to the area foreman and he is given the freedom to assign the work to his crafts with the condition that he has to accomplish jobs according to the established priority.