Use Backlog To Manage Maintenance

Your maintenance backlog target should be two to four weeks.

By Dr. Klaus M. Blache, Univ. of Tennessee Reliability & Maintainability Center

It baffles me to see how many companies fail to understand backlog, don’t have a backlog process to follow, or have one and simply don’t follow it. Maintenance backlog is the methodology of calculating the amount of work approved and waiting to be done. Yes, it’s just a calculation, based on needed and available resources, but, when handled correctly, it’s the way to manage your maintenance workload. Backlog is required hours/available hours and is typically expressed in weeks of backlog (some facilities are still using number of work orders, which provides no indication of time for planning). While many metrics can be applied, the key is to use the chosen metric consistently. Maintenance backlog work:

• should not just be the work that has passed the due date
• should be reduced with overtime, less-reactive maintenance, and/or by outsourcing
• takes into consideration the priorities of items already in backlog
• is part of good planning and scheduling
• should be organized, i.e. sort out the shutdown work (for when it’s needed); remove duplicate work orders, unapproved capital projects, and old/obsolete work orders; and then focus on all other work, based on priority
• is a factor in determining what can be accomplished with internal resources and what basic tasks should be outsourced
• is increasingly disrupted with growing reactive maintenance.

‘Ready Backlog’ is one of many key metrics. It refers to the quantity of work that has been fully prepared for execution, but has not yet been executed. See the Society for Maintenance and Reliability Professionals (SMRP, Atlanta, smrp.org) Body of Knowledge for more details and additional related definitions. According to SMRP, Ready Backlog (weeks) = Ready Work/Crew Capacity.

In the past year, I’ve seen company Ready Backlog values ranging from as low as a week to more than 15 weeks. Of course, the rate at which you can reduce a high backlog depends on the number of people you have and how much time can be consistently allotted to it without disrupting normal activities. At more than one plant, I calculated that it would take more than a year to remove the backlog, assuming nothing else happens. That means a new work order may not get completed for a year.

A backlog of less than two weeks indicates you are over-staffed. Two to four weeks’ worth (some go to eight) is generally considered good. Your backlog should be leveraged to maintain a well-utilized workforce. If the backlog gets too long, groups throughout the plant will lose confidence in your process and often start prioritizing needs as “very high” or a safety concern to get things done. Unfortunately, too many companies fall far behind with backlogged work orders and simply drop them off the schedule. My advice: Use backlog to help establish a competitive maintenance process. EP

Based in Knoxville, Klaus M. Blache is director of the Reliability & Maintainability Center at the Univ. of Tennessee, and a research professor in the College of Engineering. Contact him at kblache@utk.edu.