The Japanese Path to Maintenance Excellence
By Mike Sondalini
"A component of the Japanese production system is the equipment maintenance and how equipment criticality is determined."
In August 2002 I spent a week in Japan at the chemical plant of an
internationally renowned chemical manufacturer. While there I asked them about
how they do their maintenance. They told me about their maintenance philosophy.
And I want to pass on to you what I learnt about the Japanese way of doing
maintenance on that trip.
You will read a number of topics in the next two months. You will read about
how this Japanese company determines its equipment and component criticality.
You will learn about a new, truly effective way, of making next year’s
maintenance plan. We will cover condition monitoring the Japanese way. The
Japanese are great maintenance investigators and you will be impressed when you
learn how they do their failure analyses. We will also cover their psychology of
maintenance – the way they think about maintenance and how they look at it.
You will be astounded at their mind-set.
A Japanese way to decide equipment criticality.
How do you decide what level and type of maintenance to use on an individual
item of plant and its sub-assemblies? Not all equipment is equally important to
your business. Some are critical to production and without them the process
stops. Others are important and will eventually affect production if they cannot
be returned to service in time. While other items of plant are not important at
all and can fail and not affect production for a very long time.
As a maintainer you want to know which equipment in your plant falls into
each of those categories so you can determine your response. Furthermore you
want to know which sub-assemblies in each item of equipment are critical to the
operation of the machine.
From this information you can decide which spares to hold on-site and which
to leave as outside purchases. The equipment criticality also determines what
level of preventative maintenance to use, what type and amount of condition
monitoring to use and what type and amount of observation is required from the
operators. You can also use it to justify on-line monitoring systems to protect
against catastrophic failure.
The western approach to determine criticality is often to use either
Reliability Centered Maintenance or Risk Based Maintenance to determine
consequences of failure and then address the appropriate response to prevent the
failure. The Japanese chemical manufacturing company I visited had a novel way
of determining their equipment criticality. They based the equipment and
component criticality on the knock-on effect of a failure and the severity of
the consequences. It is the same intention as the previously mentioned methods
but they arrive at the rating and the response to it in a unique, quick
They used a simple flow chart that production and maintenance worked through
together, equipment by equipment. Those failures that caused safety and
environmental risks were not allowed to happen and either the parts were carried
as spares and changed out before failure or the plant item was put on a
condition monitoring program. Those failures that caused production loss or
affected quality also were either not allowed to happen or put into a
condition-monitoring program. And those failures that didn’t matter were
treated as a breakdown.
The flowchart let one arrive at a rating and a corrective action for each
piece of equipment and component fast. No need to spend hours and days looking
at failure modes and deciding what to do about them. If an equipment or
component loss produced dangerous situations, or if the failure stopped
production or affected quality, it was either changed out before the end of its
working life or it was put on a monitoring program.
The maintenance philosophy for every bit of plant could be arrived at in a
four-step decision process. It was very easy to use and to decide what action to
If you want a copy of the flow chart email me and I’ll send it to you.
(This is a good way to find out how many people read this far into the article.)
How to turn a maintenance plan into a strategy.
The maintenance plan my Japanese hosts showed me in August 2002 was on a big
spreadsheet. It listed all the equipment in a plant by tag number covering the
period 1994 through to 2003. The maintenance histories of problems on a piece of
equipment for the past eight years were listed. A short note detailing the month
of occurrence and the failure was made in the column of the year it happened.
For this year, 2002, and the next, 2003, the spreadsheet listed what maintenance
and modifications were going to be done on the equipment.
It was a ten-year plan the like that I had never seen before!
The ten and five-year plans I had seen were always ten and five years into
the future and never covered the past. So why did they do it that way – 1994
to 2003? They never told me their reasons. But now, as I write, it has become
clear why it’s worthwhile doing it like that. What I saw was not a plan! What
I saw was a strategy! It was a strategy to reduce the known production stoppages
and to focus the maintenance effort.
Can you see how something like that would work? You know what has gone wrong
with the equipment over the last eight years, it’s listed right there in front
of you. You can see how effective the past practices, methods and solutions have
been. From that you can wisely decide what to do over the next two years to
prevent the reoccurring problems. Instead of writing the usual ‘blue sky’ 5
or 10 year maintenance plan that no one believes anyway, you only plan for the
believable two years ahead. You write down exactly what can really be done in
the foreseeable future to reduce or prevent the real problems.
The plan for the next two years would include proposed modifications,
equipment replacements, new condition monitoring plans, etc.
Now that is a great way to make next year’s maintenance plan! It would be
one that is totally defendable and fully justifiable to upper management because
it is well thought out, rooted in getting the best return for your money and
based on the important business requirements to continue in operation.
My suggestion to cover the period beyond the next two or three years (and
only if it is necessary in your company), is to use the spreadsheet to make
forecasts. Project ahead based on what you plan to do in the coming two to three
years to fix the current problems. If you aren’t going to fix the problems
then don’t assume less maintenance in the future. Remember that a forecast is
not a plan! A forecast is a best-guess suggestion, often known as ‘blue sky
dreaming’. A plan is a set of action steps that over time will produce a
desired result. They are totally different to each other.
To get your own copy of the spreadsheet that was passed to me (It’s now
fully translated into English) please email me at info
@ trade-school.education or click "The
Japanese Path to Maintenance Excellence" to download the book. New! MP3
audio books version available
UP-TIME Publications teaches your maintenance crew engineering and asset
care knowledge so that they can solve more problems, become more knowledgeable,
make better decisions and your plant runs more reliably!
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