Efficient Plant January 2018 - 8

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Use Backlog
To Manage
Maintenance
Dr. Klaus M. Blache
Univ. of Tennessee Reliability &
Maintainability Center

Your maintenance backlog target should
be two to four weeks.

8

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I

T 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.

JANUARY 2018
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