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A
special thanks to Reliability
Center, Inc. for donating this article.
It does not show up on a company’s
balance sheet and is not usually recognized as an asset, but the data
that a business possesses is an important asset to the company. A
company with good business values can benefit from a reliability program
because it generates lots of important data. This data can be used for
reliability purposes to improve equipment and process performance,
reduce operating costs, and dramatically improve profits. To gather and
manage this data, a good Computerized Maintenance Management System
(CMMS) is extremely helpful.
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.
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- 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.
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- 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.
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- 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.
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- 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.
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- 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.
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- 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.
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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:
Failure Rates - Failures/year
MTTR - Mean Time To Restore after
failure
All Quality Parameters
Quality Reject Rates of Parts and
Supplies
Parts Usage Data
Unavailability of Parts from Stores
Vibration Data
Infrared Thermography Readings:
- Production Rates
- Operational Pluggage Rates
- Rates of Loss of Heat Transfers
- Flow Rates
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.
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