All plants have a maintenance backlog. If plants consistently have no maintenance backlog then it could be argued that they are either spending too much on maintenance, or they don’t have the required maintenance planned in the first place. Maintenance backlogs are a fact of life, and are not intrinsically an issue from a risk perspective. What is important from an insurance perspective is the volume of backlog, and how the backlog is managed. In general, risk engineers would expect to see no more than 10% maintenance backlog. By 10%, I mean that if there are 100 work orders issued to be completed in a given period, then 90% of those work orders would be completed in the specified time period.
Backlog management is an important consideration in that plans and resources need to be available to complete the outstanding work in a time frame that does not increase the risk to the plant. Here we come back to the criticality of plant, and the requirements that all work orders have some identifier as to the criticality of the work. While a CMMS may schedule the work and produce work orders, a maintenance supervisor will decide which work to carry out based on the maintenance resources available. These resources will be heavily impacted by breakdown work and emergencies, which will consume the time which has been scheduled for routine maintenance. It is imperative that these decisions are based on work and equipment criticality. Backlog management plans should include decision points which trigger the acquisition of additional labour and technical resources so that essential work is carried out irrespective of breakdown work considerations.
The best backlog systems can demonstrate that only discretionary maintenance work exists in the maintenance backlog, that critical maintenance work is never displaced by breakdown maintenance, and that additional resources are available to manage the backlog when required. The system should include senior management review of the work backlog, and automatic highlighting of work which has been delayed for more than a specified time.