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| Browse the . . . |
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| where you'll find books on
maintenance topics from A to Z. |
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| To satisfy facility reliability needs the
Computerized Maintenance Management System (CMMS) must provide for the
collection of data to facilitate Reliability study and analysis. The question
becomes how to capture this data and what type of data is needed. The purpose
of this paper is to shed some insight into the type data needed and why.
From a reliability perspective a CMMS must satisfy the following broad
requirements: |
 |
Help identify reliability deficiencies. |
|
Provide data to aid in the analysis of reliability
deficiencies. |
|
Provide reports that measure the effectiveness
of reliability corrections. |
|
| Help Identify Reliability Deficiencies |
| For the reliability professional to identify
maintenance and operational deficiencies certain information is essential.
Much of this information can be obtained by introducing shift notes that
are kept by mechanics and operators into the CMMS and analyzing tasks depicted
therein for frequency and impact. While there are tools, like computers
and software that now make it possible to sort through unstructured data
in useful ways, data manipulation and analysis is much easier when a logical
coding method is used. A brief example of what is meant by logical coding
is illustrated below. |
| Logical Coding |
| Subsystem |
Failure
Event |
Failure
Mode |
Frequency
(Date) |
Impact
(Downtime) |
| Area 6 |
Pump 14 |
Bearing Failure |
12-Jan-99 |
8 hours |
| Area 6 |
Pump 14 |
Bearing Failure |
17-Jan-99 |
4 hours |
| Area 6 |
Pump 14 |
Bearing Failure |
18-Jan-99 |
12 hours |
|
| Note: Drop Down Windows Facilitate Logical Coding |
| Compare this to the illogical coding that follows: |
| Illogical Coding |
| Subsystem |
Failure
Event |
Failure
Mode |
Frequency
(Date) |
Impact
(Downtime) |
| In Area 6 |
Pump # 14 |
Bad Bearing |
1/17/99 |
1/4 day |
| Area#6 |
Pump (14) |
Noisy Bearing |
Jan.18, 1999 |
2 weeks |
| Area 6 |
Pump 14 ? |
Bearing Failure |
25-Jan-99 |
8 Hours |
|
| Logical coding will require some training
for those individuals who write shift notes. Once training is complete
and a logical coding method is adopted, deficiencies can be determined.
Some examples of the type deficiencies that can be delineated in this manner
are: |
|
Repeat pump failures and the amount of production
lost. |
|
Repeat sprocket and/or chain failures and amount
of production lost. |
|
Chronic or repetitive leaks by service line
(e.g., steam, acid, condensate, etc.) and dollars expended to correct these
leaks. |
|
Repeat failures of systems or equipment and
the amount of production lost in total or per occurrence. |
|
Stores substitutes made and probable production
lost if the substitute fails. |
|
Trips to stores to secure parts and dollars
expended in this effort. |
|
Number of safety lockouts that occur and the
money expended in securing the lockout plus the amount of work or workers
delayed while the lockout is secured. |
|
| In identifying deficiencies like those above,
it is important to not only identify the deficiency, pump failures,
but to also identify the cost associated with that deficiency, the amount
of lost production. Also, in perusing the above deficiencies, it can
be seen that some of the deficiencies are process, leaks,
some are equipment related, equipment and system failures, and some
are administrative in nature, stores substitutes, trips to stores, and
safety lockouts. Typically, process and equipment problems are considered
reliability issues whereas administrative situations often are not. This
is a fallacy. Administrative issues like substituting for parts in Stores
because a substitute part is more easily obtained or costs less often creates
reliability issues and should be tracked. Non-value-added situations like
trips to stores and safety lockouts, while necessary, are reliability issues
and should be analyzed to minimize costs and process interruptions. In
addition, there are other reliability deficiencies that must be considered. |
| Other ways that reliability deficiencies can
be identified and analyzed is to keep track of these items in the CMMS.
The CMMS should: |
|
Identify and statistically
sample the number and type of key strokes made by control room operators.On
the surface this activity may seem unnecessary, but it is something that
should be examined periodically. The goal should be to maximize operator
attention time to the process and minimize keystrokes. The keystrokes may
be necessary to operate the process and/or equipment and to provide information
on how well the equipment and process is performing. Regardless, keystrokes
should be minimized because every keystroke is a chance for error. |
|
|
Identify the frequency
and type of adjustments made to specific machinery and equipment. It
goes almost without saying that frequent and/or large adjustments
to machinery and equipment indicates that the process is either being changed
frequently, or that the machinery and equipment is operating or was designed
unreliably. Frequent adjustments are sometimes taken for granted and go
unreported for ages. |
|
|
Identify the time
it takes to ramp down, stay down, and ramp up when an outage or production
interruption occurs. Standards for ramping down (shutting down)
and ramping up (starting up) should exist or be established. If possible,
deviations from standard should be noted and explained. Serious deviations
should be investigated. For the length of time the equipment or process
stays down, standards by reason (i.e. felt change, filter change, maintenance,
etc.) should also be established and deviations noted. |
|
|
Identify the frequency
and impact of shortages of parts and operating supplies, such as spare
parts, raw materials, additives, filters, blanks, hoses, etc. These
items, commonly known as stock-outs, can have a serious impact on production.
If the stock-out is for a critical item the impact can be devastating.
Therefore, stores stock items should be assigned criticality codes and
stocked accordingly. All stock-outs should be noted. Care should be taken
to designate a stock-out whenever a substitute part is used because the
item wanted was not available. A situation comes to mind where an electrician
wanted a twenty five amp heater and because it was not available in stores
used a 23.5 amp heater as a temporary fix. The piece of equipment involved
in that temporary fix experienced numerous resets for months before that
condition was uncovered and corrected. |
|
|
Identify and keep
track of the runtime for each process and each piece of operating equipment
before a shutdown occurs. Runtime must also be tracked for vehicles,
fork trucks, cranes, tow motors, and other types of motorized equipment.
Runtime is essential for calculating Mean Time Between Failure (MTBF),
an important reliability indicator, for equipment that is not run continuously
and useful for calculating MTBF for equipment that is run continuously. |
|
|
Identify each human
interface and make potential inferences when problems occur as to which
interfaces may have contributed to the problem. For example,
in an area that experiences heavy failures, the supervisor to hourly employee
interface may be contributing to the problem. |
|
|
Identify product flow
slowdowns due to ramping, equipment failure, and administrative order.It
is a reliability concern whenever production rates are curtailed for any
reason. Whenever this happens, the time the slowdown started, the reason
for the slowdown, and its duration should be captured. |
|
|
| Provide Data to Aid in the Analysis of Reliability
Deficiencies |
| Once reliability deficiencies have been identified,
it is imperative that these deficiencies be analyzed to determine root
cause and corrective measures initiated to improve reliability. The analysis
and subsequent solutions can be aided by such CMMS data as discussed in
these five major categories: |
|
Process Supporting Data |
|
Machinery Supporting Data |
|
Other Supporting Data |
|
Direct Failure Information |
|
Financial Information |
|
| Process Supporting Data |
| Depending on the deficiency, certain process
supporting data is necessary. In order to cover the full range of possible
deficiencies, the list of supporting data becomes fairly large. Included
in this list would be a list of processing exemplars and where to obtain
actual specimens or samples. Also included would be the results of job
audits, quality parameters that must be met to assure a first quality product,
and the data and analyses of previous process failures. In addition, a
continually updated list of experts in various disciplines, and on various
machinery and processes, should be maintained and readily available in
the CMMS. Finally, a common problem list should be maintained. The problem
list should include a list of chronic problems within the same process
such as yield deficiencies, pluggage problems, quality problems, and deteriorating
heat transfers. |
| Machinery Supporting Data |
| A significant amount of machinery supporting
data must be maintained in order to analyze and resolve reliability deficiencies.
This data should be stored in the CMMS and should include machine histories
that delineate all past repairs and adjustments. It should also include
all previous failure analyses on the same equipment. It should also include
a listing of the clearances for the machine in question, plus a listing
and pictorial representation of the spare parts used in that particular
machine. Additionally, for critical machinery the CMMS should include graphics
capable of showing 3D cutaway views of the machine with parts installed.
Finally, the CMMS should include a list of quality parameters for the machine
and a list of past deficiencies in part quality. |
| Other Supporting Data |
| Besides process and machinery data, certain
other data is necessary to completely resolve reliability deficiencies.
This data should be stored, maintained, and retrievable from the CMMS.
In this category of data would be such things as: a listing of the applicable
operating, maintenance, and safety procedures for the area in which the
reliability deficiency exists, a list of trained failure analysts for the
site or company, and area training records showing past training experiences.
For example, the training records should include who was trained in what
subject or skill and particulars about the training. Finally, this category
should include a vendor list including phone numbers and who to contact
for each vendor. |
| Direct Failure Information |
| Many reliability deficiencies involve chronic
process or machinery failures. Until resolved chronic failures occur over
and over again When they do occur, it is important that direct failure
information be gathered and maintained in the CMMS. This data must include
operating data for the period of time prior to and at the time of failure,
and observations of witnesses prior to and at the time of failure. Gauge
readings prior to and at the time of failure should be recorded, and observed
liquid spills or gas releases, their timing, volume and/or size should
also be recorded. If the failure involved an explosion, the exact location
of parts immediately after the explosion occurred should be recorded. Sketches
and photographs of the failure site, and eyewitness accounts of people
interviewed immediately after the failure should also be recorded. Failed
parts should be tagged, bagged, and saved for the failure analyst, and
a listing of the failed parts and their present location should be recorded
in the CMMS. Finally, operational paradigms should be identified and recorded.
For a variety of reasons, operational paradigms are usually best secured
by outside experts. |
| Financial Information |
| Applying scarce resources to analyze and
resolve reliability deficiencies must be cost effective. To assess cost
effectiveness and to determine the impact of failures and slowdown on plant
financials, certain financial information is necessary. Although there
is a reluctance by some to put financial information in the CMMS, it works
best for the failure analyst when this is done. The following financial
information is suggested: production rates, parts usage rates, product
output, unit cost, expected return on investment, downtime cost per unit
of time, fully loaded hourly rates or a standard hourly rate for assessing
repair costs, value added costs by department, cost accounting data used
internally to evaluate costs, and overhead costs. |
| Provide Reports that Measure the Effectiveness
of Reliability Deficiency Corrections |
| Once a solution to a reliability deficiency
has been devised it has to be tested and tracked on two levels, operational
and financial. To do this certain additional data must be available in
the CMMS. Briefly, the following operational and financial data is required: |
| Operational Level |
| On the operational level, the following data
should be stored, maintained, and retrievable from the CMMS: |
|
Slowdowns or Rate Reductions |
|
| Most of the above items have been discussed
earlier in this paper or are self explanatory. However, a few items are
worth mentioning again. For example, whenever an equipment or process failure
occurs, the equipment or process that failed, the date and time of the
failure, and its runtime to failure should be recorded. Additionally, the
time to restore the equipment or process should be recorded. Using this
input, the CMMS should tabulate the number of failures, the mean time between
failures, and the mean time to restore after failure. |
| Other than to count incoming stores stock
items to ensure against shortages and a visual inspection to spot obvious
damage, many companies do not inspect stores stock items against specifications.
Where possible and feasible this should always be done. In addition, there
should be a provision in the CMMS for recording stock item quality defects. |
| In addition to quality defects of parts, quality
parameters for all products manufactured at the facility should be retrievable
through the CMMS. These parameters and how well the products are meeting
the parameters should be stored in the CMMS or retrievable through an interface
with other plant systems, for example the Quality Control system. This
concept also applies to production data for such things as production rates,
flow rates, pluggage rates, etc., and to non-destructive testing data for
things like vibration data, infrared thermography readings, etc. This type
data, which is useful to the failure analyst, does not have to reside in
the CMMS, but should be retrievable from the CMMS. |
| Financial Level |
| On the financial level, trends of certain
financial information should be tracked and maintained in the CMMS or retrievable
from the CMMS through an interface with other plant systems. Trends of
product output, unit cost, customer complaints, on-time deliveries, stores
inventory, and raw material inventories (intermediate and final product)
are very useful to the reliability professional for assessing the impact
of reliability deficiencies as well as evaluating the solutions to these
deficiencies. |
| Summary |
| A properly used and set up CMMS is a powerful
tool for enhancing reliability efforts. A word of caution though, an improperly
setup and used CMMS can have an equally negative impact on reliability.
The trick is to do it right in a consistent manner. Like any tool, CMMS
must be maintained and used properly to achieve the greatest potential
possible. |
| William C. Worsham is a Senior Consultant for Reliability
Center, Inc. Mr. Worsham has over 30 years experience in the field of Maintenance
and Reliability program managment. He has participated in and led teams
in the development, design and implementation of three separate maintenance
management systems. He has also participated in the design and implementation
of specialized reliability inspection programs such as lubrication scheduling,
vibration monitoring, instrument inspection and preventive maintenance.
Mr. Worsham is a practitioner of root cause analysis in the field with
his clientele as well as an educator. He can be contacted at 804/458-0645
or bworsham@reliability.com. |
| Charles J. Latino is president & founder of Reliability
Center, Inc. Mr. Latino is a chemical engineer with a background in psychology
and human factors engineering. He is a leader in the development of an
integrated approach to achieving greater reliability in manufacturing and
industrial systems and processes. He has served as consultant to many companies
in the United States and abroad. He is the author of Strive For Excellence...The
Reliability Approach. Mr. Latino can be contacted at 804/458-0645 or info@reliability.com |
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