What is maintenance backlog?
Maintenance backlog, as a maintenance metric, is a measure of required maintenance work that has not yet been completed.
Usually measured in work days or weeks, the maintenance backlog as a metric quantifies the amount of time required for a defined number of workers to complete all pending maintenance tasks. Maintenance backlog is composed of activities related to preventive maintenance and any other outstanding maintenance such as required corrective maintenance.
It goes without saying that not all tasks in the backlog are equally urgent. Having some backlog is not necessarily a reason to panic—it can even be an indicator of optimized staffing. The dangers of maintenance backlog creep in when maintenance schedules are disrupted by emergency work and an inefficient prioritization model.
Neglected tasks in the maintenance backlog become deferred maintenance, inevitably causing more breakdowns and serious downtime. Breakdowns require immediate unplanned maintenance tasks that in turn disrupt scheduled activities. Disruptions to the schedule push more tasks into the backlog to continue the vicious cycle.
How to prioritize the maintenance backlog
Prioritization of maintenance backlog can be a balancing act considering high-level factors such as criticality to production, impact on customer service, maintenance costs, and time required to complete. Prioritization models would typically assign weights on each of these factors to come up with a decision process to identify which tasks to perform first.
A research paper published in 2018 meticulously investigates existing studies of how various prioritization models are utilized by manufacturing companies. The research discusses how plants go to great lengths to come up with a robust matrix to reduce risks and minimize costs when prioritizing maintenance tasks. The study notes that industrial practices can be highly dependent on the maintenance team, subjective to the knowledge and experience of the maintenance planners.
To effectively manage the backlog, maintenance tasks need to be defined for the maintenance and production teams to agree on a timeline of execution. The following specific areas can help assess which tasks and which equipment are more critical:
- Machine utilization
- Failure rate
- Last repair
- Maintenance time and cost
Based on the task list and schedule, resources must be planned out appropriately. Discuss with stakeholders the required staffing and distribution of workload, and whether overtime or additional personnel are needed.
How much backlog is too much?
Maintenance backlog provides a list of things to do over a certain period of time. Having some amount of backlog is generally acceptable. Having no backlog may be indicative of overstaffing – the idea is not to eliminate the backlog, but to manage it.
A backlog of around two weeks worth of tasks per technician should be a good value according to this article on backlog maintenance. The exact ideal amount of backlog may vary for each business, but the idea remains that some amount of pending work can be a useful metric when managed properly.
The important point in measuring maintenance backlog is defining how it is measured. Agree with the team and with your stakeholders on what constitutes the maintenance backlog.
How much of it is preventive maintenance, and how much of it is corrective maintenance? Differentiate between tasks and delegate maintenance work accordingly so that the workforce is utilized more effectively towards managing the backlog.