Maintenance Backlog

What is a maintenance backlog?

A maintenance backlog provides a list of maintenance tasks that are currently on hold. It contains approved maintenance work that needs to be planned and/or scheduled. 

In the photo below, you see how the list of deferred tasks looks in Limble CMMS.

There are many different reasons tasks may end up in a maintenance backlog. Oftentimes, the culprit is a resource issue such as:

• Lack of staff, tooling or spare parts to complete the work
• Higher priority tasks taking precedence
• Difficulty confirming a suitable window to shut down production

Table of Contents

What industries use Levels of Service
Why go through the trouble of defining LoS?
Common criteria used to define Levels of Service
Defining Levels of Service in your business
Understanding LORA

The utility of a maintenance backlog

The term backlog carries negative connotations. However, a maintenance backlog is a useful part of a well-functioning maintenance program. 

It provides a pool of tasks to help maintenance schedulers manage and optimize the team’s workload. It also ensures that nothing slips through the cracks by having a list that can be regularly revisited.

A maintenance backlist is never static. It grows and contracts based on resources, workload, and production availability. However, it also provides important insight into:

• Equipment reliability 
• Work efficiency 
• Staffing levels
• Maintenance program effectiveness.

A consistently long maintenance backlog often implies systemic bottlenecks that need to be addressed, like incorrect inventory min/max levels that cause poor spare part availability.

How to calculate your maintenance backlog?

Looking at the length of your maintenance backlog is not a good way to assess the health of your maintenance system. Instead, use work days or work weeks as a metric. 

This simple method uses the hours estimated for each task to quantify the amount of work included in your backlog. If you wish to know how many work days it would take to clear the list, divide the total number of task work hours in the backlog by the total number of productive hours the maintenance team can complete in a day. 

Here’s the formula:

If you prefer to use work weeks as your metric, substitute the daily productive hours with a weekly figure.

Let’s go through one example to see how to apply the formula in practice.

Assume you have a maintenance backlog of 85 tasks. When you add up the estimated time to complete each task, you end up with 192 work hours sitting in the backlog. 

Your staff has four maintenance technicians, each working eight hours daily. Removing lunches, breaks, and admin time, each technician is productive six hours daily or 24 hours a day for the entire team. 

Applying the above formula to these figures gives us the following:

Backlog Workdays = Total backlog hours / Total team productive hours

Backlog Workdays = 192 hours / 24 hours

Backlog Workdays = 8 workdays

Therefore, if your maintenance team was devoted entirely to clearing the backlog, it would take them eight days to complete all of the tasks. 

Remember that this number will regularly change due to tasks being cleared and new tasks being added.

What if your backlog is too large?

If you have an overwhelming backlog of deferred maintenance tasks, or just notice a concerning growth in your backlog, there are some steps you can take to get it under control. 

1. Clean and prioritize your maintenance backlog

Your first step is to review and clean the backlog to ensure it is current. List the tasks by age to see how long have they been sitting in the backlog. 

• Consider removing tasks that have been on the backlog for 12 months or more unless there is a specific maintenance window you have been waiting for. 
• If the lack of a task’s completion hasn’t affected the organization, consider removing it or lowering its priority or frequency in your schedule.
• Remove duplicate work or tasks that are no longer relevant due to changes, new equipment, or an updated maintenance plan. 
• Prioritize the remaining maintenance tasks based on their impact on equipment reliability, asset performance, or business continuity.

2. Review your outstanding work orders

Next, review your work order system to understand:

• How many work orders are open
• How long it takes to close them
• The number of duplications and invalid requests. 

A properly functioning work order system should see all work orders completed within four days, preferably 24 to 48 hours.

If your work order system is inefficient, it may hide the magnitude of the outstanding work. In this case, the maintenance backlog will also provide misleading information on your maintenance system’s effectiveness and efficiency.

3. Gain control with a CMMS

Now that you have a clean maintenance backlog (and hopefully a clean and functioning work order system), it’s time to lock it into a computerized maintenance management system. With CMMS software, you gain insight and control over the entire workflow, from initiating a work request to closing out the work order.

A CMMS allows managers and supervisors complete oversight of your maintenance system. It prevents informal systems for work requests, ensuring all actions are documented and tracked. It also enforces review times and actions, and even helps identify duplicate requests. 

A CMMS can flag overdue and critical items and monitor a backlog’s trends. 

As an added bonus, a CMMS software will also log a complete audit trail from work request initiation to scheduled task completion, showing individuals involved and actions taken, as well as relevant dates, times, and spares used.

4. Review strategies for clearing the list

Tidying the system and getting it under control with a CMMS may be enough to reduce the backlog to an acceptable level. However, if you still have an excessive maintenance backlog, you must explore other methods. 

You can apply the right remedy only when you understand why so many of your maintenance tasks get postponed:

• A lack of human resources: consider offering overtime or employing temporary maintenance contractors to assist. 
• The maintenance department is undertrained: offer extra training or mentoring to your employees or hire additional staff.
• The maintenance program is not optimized: implement preventive maintenance and a CMMS to plan, organize and track your maintenance process. If the budget allows, predictive maintenance with condition monitoring sensors for critical assets can also help you use your internal resources wisely.
• A lack of inventory: identify supplies that are critical to keeping your equipment running — prioritize those items and stock them first.

There’s rarely one single way to reduce the size of your maintenance backlog. Greater insight into what is causing delays will help you prioritize different solutions.

Should you aim for zero maintenance backlog?

If you have any practical experience, you know that having zero outstanding tasks is simply not realistic. There will always be delays while ordering parts, waiting for tools to become available, or negotiating a suitable time with production to complete a task. 

If an organization claims it has zero maintenance backlog, there is either a problem with its work order system or its maintenance department is vastly over-resourced.

Having some tasks on the backburner is fine. The real question is, how many is too many? 

Large manufacturing organizations with best-in-class maintenance practices average five to eight weeks of backlog. In comparison, a small organization with a couple of efficient technicians can have two weeks worth of backlog. 

You must decide what feels suitable for your operation, but aiming for six to eight weeks is a good target.

Size is not the only thing that matters; the trend is equally important. If the backlog of work grows bigger week by week, you’re losing the battle. An increasing trend over time suggests you need to review your backlog and maintenance practices to understand the root cause.