The maintenance backlog is an incredibly important part of the overall maintenance process. In essence, the backlog is all the maintenance work that has been approved but has not yet been completed. A completed work order, by this definition, cannot be part of the backlog. This does not mean that the work orders in the backlog are solely reactive maintenance. Your backlog can easily include preventive or even predictive maintenance activities.
Managing the maintenance backlog is vital for determining how work orders will be prioritized to assure the greatest possible uptime for all physical assets. This is especially true in the case of assets that are critical to production, but it really applies to all the equipment and machinery under your charge. Properly managing the maintenance backlog requires you to sort and filter the work that must be done. The primary reason, of course, is to ensure that critical assets do not break down. A secondary reason is to prevent work orders that aren’t ready from entering the scheduling funnel.
A work order that’s missing any vital information should never make its way to the maintenance crew. Exactly what is considered “vital” will vary significantly from organization to organization, but it’s hard to imagine a work order that wouldn’t at least include the name and location of the asset, a description of the problem and the scope of work needed to rectify it, any parts or tools required, health and safety information, the various dates the order was filed, expected to be completed, and so on. It would also usually include the names and departments of the people requesting the work, how long the work should take to complete, and the work order’s relative priority.
From this, we can see that a large part of properly managing the backlog lies in ensuring that only accurate and complete work orders should make their way into scheduling.
We should also mention that there’s another definition of backlog that crops up occasionally, viewing it as the collection of work orders that are overdue. Thinking of the backlog this way may lead you into trouble.
Don Armstrong of Veleda Services, writing for Reliable Plant, sums up the issue: “The second definition is that a “backlog” is just those work orders that have passed their “required by” date. This definition should not be used because it is not logical. Most maintenance departments have a reasonably fixed number of tradespeople who perform work from work orders generated more or less at random."
“When a work order is initiated, the date on which the work will be completed depends on its importance relative to the work already in the backlog, which is known, and also the work orders that will be generated in the future, which are unknown. The result is that any “required by” date assigned when a work order is initiated will be just a wild guess and usually wrong. Assigning a “required by” date should be limited to those few work orders that have a genuine deadline. Otherwise, these dates will be in conflict with the objective of always working on those jobs that have the greatest value at any time.”
Using the above definition of backlog interferes with prioritization. Work requests should be dealt with in accordance with how important they are to continued operations. We’re not going to say that due dates are meaningless. There is usually some reason why the due date was assigned in the first place. However, completing work by a particular date should never take precedence over prioritization and criticality.
You will never have infinite resources to accomplish the work that needs to be done. In its simplest terms, the maintenance department needs to focus on the tasks that provide the greatest return. Doing this effectively relies on efficient planning, scheduling, and prioritization of maintenance activities.
First come, first served is a good way to run a lunch counter and a terrible way to plan maintenance activities. A high-priority job on a critical asset should naturally take precedence over low-priority work on a less critical asset.
Creating a priority index is a relatively simple process. Briefly, you assign a criticality number from 1 to 100 to every piece of equipment, with higher numbers indicating that the asset is more critical. Run through the process again, but this time assigning priority to work orders. Again, the higher the number, the higher the priority.
Priority Index = Asset Criticality x Work Order Priority
Now multiply the asset criticality score by the work order priority score. The result is the priority index. Now you can schedule work by priority index, secure in the knowledge that resources are going towards the most important work.
It is essential to confer with operations when determining your priority index. At the very least, have a member of the operations team look over your asset criticality index and see if they agree with your rankings. If there are differences, alter your criticality assessments as needed to line up with operations. For more on asset criticality, please see our white paper "Equipment Criticality and The Prioritization of Work Orders."
You will also need to examine all existing work requests. Watch out for duplicate work requests, work orders that may have already been completed, and work orders that are missing vital information. You will need to remove all of these from the backlog for now. A work order can be moved back into the backlog once all the required information has been gathered. For more information on creating a priority index, please see "Creating a Work Priority Index: 4 Essential Steps."
Once you have your priority index in place and you’ve cleared all the work orders that don’t have enough information, you should be ready to move on to planning and scheduling the work orders that are ready for processing.
Planning and scheduling the work are obviously very important parts of managing the maintenance backlog, but the topics are too complicated to go into here. For a good starting point on planning and scheduling best practices, please see "What's Your Maintenance Mindset? Four Best Practices Schedulers Should Follow When Creating a Maintenance Schedule."
The only work orders that should be in a healthy backlog are those that are ready for planning and scheduling. Contact of member of the Prometheus team for more information on how we can help you manage your maintenance backlog.