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RE: equipment criticality
This month's topic is "equipment criticality" and using
OEE to evaluate it. This topic is in respond to our reader Davie's inquiry.
Hi everyone, and welcome to November's issue of our Feed Forward Newsletter! My name
Don Fitchett, the author of
"The Maintenance War Newsletter". This first area of the
newsletter is for introductions and commentary. I would like to comment on
how the new Feed Forward Publications company is doing and then tell you a
little about the new resources we have added to our Feed Forward Publications website.
If you are reading this newsletter after someone forward you a copy,
you can find an online version on the newly redesigned website www.feedforward.com.au
This newsletter and the new website have met with great acceptance and
success. I first and utmost want to thank the 1000 plus newsletter
subscribers and our customers who purchased over 70 ebooks and CDs in
October (not including the sales that our affiliates made!).
We know that success could not have come without our subscribers and
customers spreading the word. We have strived not only to improve customer
service within our own company, but our affiliates too. I would like to personally
thank a few of our affiliates who have worked extra hours last month to
update our product listings on their websites.
Sutton Technical Books has worked with us throughout the month updating
and listing our new products. Sutton Books specializes in a more detailed,
engineering and theory type books. If you have need for these type
publications, please give them a visit. (Sutton Titles on our site: Operating Procedures
for Process Plants, Fault Tree Analysis)
Perspective CMMS (PEMMS) has also updated and list some of our new
products. A very valuable aspect of PEMMS is that their material is non
CMMS vendor biased. You get the expertise of a CMMS consultant without a
particular software vendor being promoted. (PEMMS Titles on our site: The CMMS Selection KIT,
The CMMS Insider's Guide)
Besides adding new titles for you to download, we have added many free
resources. In line with this month's topic "equipment criticality and using
OEE to evaluate it." we present the newly published article
- Overall Equipment
Also in our Resources:
Articles area we have our first Technical Writing "Finite
Element Analysis in Structural Design" graciously donated by
ARTECH engineering. If you have a 2-5 page technical brief you would like
to donate, please contact
We have also added many new free downloads in our Resources:
Downloads area. Too many to mention here. hope you enjoy and profit
from all the resources we found for you this month.
The maintenance manager while face with the task of adopting a standard
methodology to assign equipment criticality, is faced with a world of
solutions to sift through. Many have opted for the oldest and least
"Who ever screams the
Although I am may be subconsciously biased, I honestly believe Mike
Sondalini's advice to be a sound and down to earth method. I found the
section "Equipment Criticality" in his book The
How to SMASH Maintenance Advisor, to be simple and logical. I like
Before I present an excerpt from Mike's book, I would like to answer
our readers question of how OEE should be used in the criticality formula.
Have you ever seen the show "The weakest link"? That is what
your equipment/area with the lowest OEE percentage is.
If you take my advice in this
month's highlighted article and calculate corresponding monetary values (TDC)
with each cost center's OEE, you will know which equipment/area will be
burning the most money up. The true cost of downtime should be a high
factor in assigning criticality.
Actually OEE measures the main factors of production and quality, but
does not measure the number one factors of hazards, environmental and
safety. Those need be factored in separately and given the extra weight
Below is an excerpt on the subject from Mike Sondalini's book...
How to SMASH Maintenance Advisor
"The two approaches often used to determine criticality is either
Reliability Centered Maintenance or Risk Based Maintenance. Both methods
determine the consequences of failure and then address the appropriate
response to prevent the failure. One other way of determining equipment
criticality is to consider knock-on effect of a failure and the severity
of the consequences. It is the same intention as the previously mentioned
methods but it arrives at the rating and the response
in a quick four-step process.
People from operations and maintenance work through it together,
equipment by equipment, using the simple flow chart
below. Those failures that cause 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 is put on a condition monitoring
program. Those failures that caused production loss or affect quality is
also not allowed to happen or put into a condition-monitoring program. And
those failures that didn’t matter are treated as a breakdown.
The flowchart lets one arrive at a rating and a corrective action for
each piece of equipment and component. If an equipment or component loss
produces dangerous situations, or if the failure stops production or
affects quality, it is either changed out before the end of its working
life or put on a monitoring program."
(You can find the flowchart Mike refers to on page 159 of his book
How to SMASH Maintenance Advisor" the flowchart simplifies
and standardizes the criticality decision making process. If you would
like to download the book today for US$20 you can use this buy it now link
A more colorful representation of the criticality flowchart can be
found in Mike's book "The Japanese Path To Maintenance
Excellence". Below is an excerpt from page 10 of
this book explaining the Japanese criticality rating scale.
"The SABC is the criticality rating scale. On the chart you notice
that equipment gets an ‘S’ rating when it is never permitted to fail
because of serious danger to life and the environment from a failure.
Under the ‘S’ rating parts are replaced before they reach the end of
their working life.
An ‘A’ rating also requires parts to be changed before the end of
their working life but that is because of the production problems a
failure would cause. A ‘B’ rating required condition monitoring. And a
‘C’ rating meant breakdown maintenance was acceptable. The SABC chart
is both a criticality scale and a maintenance strategy decision
If you would
like to download the book today for US$12.50 you can use this buy it now link
Below are some of the best resources to help you with deciding
equipment criticality scores.
Analysis - Use it to optimize your plant's four key drivers—product
quality, production volume, safety and finished goods inventory. (By David
Berger, Contributing Editor to Plant Services)
Order Prioritization - this article has a basic recommendation for
determining Equipment Criticality and has been posted on several popular
maintenance sites. (By Daryl Mather, Australia :>)
risk and reliability based methods to score criticality - touches on
an important factor in determining criticality. The probability of
failure. (Capstone Engineering Services, Inc.)
downtime cost, maintenance cost and criticality - While this is not an
endorsement of their product, I do think it's fine example of accounting
for all factors in the decision making process. (Zentech International
Best regards and thanks for being a subscriber to this
Feed Forward Publications
Tel : (573) 547-5630
www.feedforward.com.au 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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