In its simplest sense, maintenance scheduling matches the availability of maintenance labour and materials to the requests for these resources. However, if maintenance scheduling were that easy, it would not be listed as one of the major problems for maintenance managers. Scheduling involves the pre-requisites mentioned in the previous newsletter, such as good job plans and identifying the status of the work order. It will then progress to scheduling work when resources are available and completing the work when scheduled.
First, the planner must determine the available labor capacity for the scheduling period (usually a week). The formula for determining the total gross capacity (TGC) for the week is:
TGC = (Total Technicians X Total Hours Scheduled) + Total Overtime Planned + Contract Labour Planned
Secondly, the planner must determine the weekly deductions (WD) from the TGC. It is typically:
WD = Average Hours of Unscheduled Work (weekly) + Average Absentee Hours (weekly) + Average Hours of Standing or Routine Work (weekly) + Average hours of Miscellaneous Activities (weekly average of hours spent in training, meetings, etc.)
Finally, the formula for the available labour capacity is:
Available Weekly Labour Capacity = TGC – WD
This will let the planner/scheduler accurately project the hours of maintenance activities that can be realistically expected to be completed during a weekly schedule period.
Once the labour capacity is determined, the planner is ready to begin developing the schedule. Using the priority and the status of the work orders, the planner will build a list of work orders from the backlog for the schedule.
(NOTE: emergency work and high priority work that should be completed in the next few days should not be in the backlog nor should this work be scheduled for next week. The hours for this type of work are already factored in the labour capacity calculation in the WD calculation.)
Planners use the status of the work order to begin the listing. All work already in process should be scheduled first in order to eliminate jobs that are already partially completed in the backlog. These jobs would be sorted within this status by priority. The next status would be those work orders previously scheduled, but not started. These also would be sorted by priority within the status. The next would be the work that is ready to schedule, again sorted by priority. The listing might be as follows:
|W.O. #||Status||Priority||Date Needed||Est. Hours|
|101||already in process||10|| ||10|
|102||already in process||9||4/21/11||16|
|103||already in process||9||4/30/11||14|
|104||previously scheduled||10|| ||6|
|107||ready to schedule||9|| ||12|
|108||ready to schedule||6|| ||6|
|109||ready to schedule||3|| ||2|
|110||ready to schedule||2|| ||4|
|111||ready to schedule||2|| ||8|
|ready to schedule|
Planners then deduct the hours required to do each work order from the available weekly labor capacity for the craft group. When they run out of hours of crafts labor available, they can no longer expect the crew to complete any additional jobs for the next week. (Unless more hours are added through overtime or contractor employees) Those remaining work orders on the list would go back into the backlog for scheduling in the future.
Next, the planners take the schedule to a management meeting where they present what is scheduled for the next week. The maintenance manager, operations and facilities managers, and engineering manager may request some changes. Planners make those changes, perhaps deferring some work orders in favor of getting others completed. Once agreement has been reached about the schedule, planners finalize it and distribute copies to all parties involved, usually on the Friday of the preceding week. In this way, they insure that there is complete agreement about the schedule before the week starts.
While this method may appear simple, it does work well for most maintenance organizations. The method is scalable and a spreadsheet or database can be constructed to help planners/ schedulers use this method with any CMMS/ EAM system.
While scheduling may seem to be a complex assignment; it does not need to be so. When coupled with good planning and utilizing a capacity filtering technique, good accurate schedules can be produced. The schedule can then serve as a good communications tool between the maintenance, operations, and engineering departments.