Have you ever wondered why your predictive /condition based maintenance program is not as effective as you think it should be? It has been more than 25 years since the wide spread introduction to predictive maintenance tools/instruments and condition based maintenance practices and still many PdM/CBM programs struggle to get full support from management and that is because many of them struggle to be effective in increasing the reliability of their plant operations and showing and effective payback to their management. Over the year I have seen hundreds of PdM/CBM programs. All of the effective programs that I have been involved with, basically 12 essential elements. They are as follow:
- Definition of the Process
- Leadership and Coordination
- Organization with Clear Roles & Responsibilities
- Training and Qualifications
- Technical Basis
- Guidance for Application of Technology
- Information Integration and Management
- Prioritization and Scheduling of PdM/CBM Work
- Work Closeout and Maintenance Feedback
- Clear Goals and Performance Measurement
- Calculation and Reporting Cost-Benefit and Return on Investment
- Continuous Improvement
Does your predictive maintenance / condition based maintenance program have these essential elements?
Tags: CBM, Condition Based Maintenance, condition monitoring, equipment reliability, maintenance practices, maintenance programs, PdM, Predictive Maintenance
Perceived Negative Change
Perceived Positive Change
Tags: Asset Management, Change management, Condition Based Maintenance, culture change, equipment reliability, Human Response to Change, maintenance, maintenance practices, maintenance programs, Predictive Maintenance, Preventive Maintenance, Reliability Centered Maintenance
Over the last 25 years of my consulting on asset management, equipment reliability and maintenance practices, it has become apparent to me that the outstanding programs in these areas all share the following common characteristics:
- Excellent Personnel
- Effective Organization
- Broad Support
- Quality Environment
- Comprehensive Program
- Measurable Standards of Performance
- Commitment to Improvement
- Regular Reporting
EXCELLENT PERSONNEL
If there is a single common characteristic of “World Class” maintenance it is the excellent people found at the heart of every successful program. A “World Class” program begins with people. A careful process assures that the best available people are responsible for such vital tasks as condition monitoring and analysis. Their shared attributes include commitment, motivation, enthusiasm, and an eagerness to learn. These successful people are willing to advocate their conclusions, challenge conventional practices, and work as a team to resolve differences and disputes among themselves. One supervisor summed it up — “these people are fun to be around”. Thus, the ideal program; dedicated personnel who work well together and challenge one another to achieve excellence.
EFFECTIVE “FLEXIBLE” ORGANIZATION
“World Class” maintenance programs are increasingly team oriented and self directed. Companies at the leading edge have implemented flexible, multi-function teams with ownership and end to end responsibility for a specific process or system. These teams are made up of operations, maintenance, engineering, and other functions needed to fulfill the mission — within a flexible organization structure to achieve maximum efficiency. Gone are the days when operations destroyed a pump due to insufficient flow or maintenance left a machine misaligned under pressures of time. Everyone is on the same page, working to achieve the same objective — optimize production.
Within the flexible organizational structure, there is a commitment to long term efficiency that includes planning and scheduling. Maintenance requirements are prioritized and closely coordinated with operations/production to maintain availability at the highest possible level. This process seeks to minimize the necessity for emergency and overtime work.
BROAD SUPPORT
“World Class” maintenance programs consistently enjoy broad support ranging from the plant and operations management to the mechanics and equipment operators that are actually performing the work. Everyone is well aware of their role and contribution to success. This support ranges from management focused on encouragement, facilitation, and rewarding contribution to the level of coordination and cooperation between maintenance, production, and engineering within a team structure.
QUALITY ENVIRONMENT
“World Class” maintenance organizations all have quality facilities that are clean, well organized, and present a professional appearance. Participants take pride in their surroundings. This in turn builds the commitment, enthusiasm, and motivation that are vital ingredients for success.
A quality environment includes ongoing training and education. Multi-disciplinary cross training to promote versatility, attendance at professional meetings and conferences, and compliance with proficiency standards demonstrated by professional certification are all vital parts of the quality environment.
Advanced skills, proficiency, meeting objectives, and successes are all rewarded within a “World Class” program. Rewards range from promotions and/or monetary bonuses to participation in out-of-town technical conferences and recognition in plant and corporate publications.
COMPREHENSIVE PROGRAM
A “World Class” comprehensive maintenance program begins with a mission statement that defines the goals and objectives of the program in words that everyone can understand. The goals and objectives must be both achievable and measurable using well defined performance indicators , e.g. increase availability to 98.5%, reduce maintenance costs to $10 per horsepower.
“World Class” maintenance programs include an optimized mix of condition directed, time directed, proactive, and reactive maintenance. Condition measurements are utilized to replace or extend the intervals between time directed/planned maintenance tasks and to direct equipment overhauls.
A computerized maintenance management system (CMMS) is an integral part of “World Class” maintenance. The CMMS tracks scheduling requirements for both preventive and predictive tasks and generates work orders that accurately tracks cost. The best systems issue individual work orders for planned maintenance tasks and repairs, specify the work procedure with helpful hints and pitfalls, and clearly states safety and quality standards/ acceptance criteria. Accurate equipment histories are constructed by requiring entries of work accomplished, including conditions found, parts replaced, and time expended, before a work order can be closed. The benefit/cost of preventive maintenance must be easily available by comparing conditions found with cost. A “World Class” CMMS system includes facilities for automatically identifying common failures by cause, equipment, manufacturer, and model number.
The condition assessment program includes mechanical vibration, lubricating and hydraulic oil analysis (wear debris and chemistry), infrared thermography, electric system analysis and motor static and dynamic (current) analysis, ultrasonic testing for leaks and electric discharge, hydraulic and aerodynamic performance (efficiency) and operating history.
In addition to the well recognized use of vibration for condition monitoring and machine protection, “World Class” organizations require vibration measurements immediately following repairs to validate equipment condition and assess the quality of the repairs.
Assuring the integrity of lubricating and hydraulic oils includes controlled storage, testing before use, and reporting overdue requirements for testing and/or changing operating fluids. Major monetary savings have been demonstrated by basing lubricating and hydraulic fluid changes on test results rather than operating hours. This also reduces the cost of waste oil disposal.
Infrared thermography is performed on a regular scheduled basis to high voltage distribution equipment, switchgear, breakers, motor starters, transformers, and connectors to detect overheating caused by loose connections or failing windings. One “World Class” organization took the added step of installing UL approved lockable doors on dry transformer enclosures. This vastly improved efficiency by reducing the time for thermographic inspections of vital transformers from several hours to less than ten minutes.
“World Class” organizations also utilize infrared thermography for regular insulation and refractory surveys measuring tank levels, checking valve leakage, and many other mechanical system surveys. Thermography is a powerful tool for troubleshooting and for regular route based monitoring programs.
Electrical transformers are monitored and tested periodically, including regular evaluation of oil condition and gas content.
Electrical tests: phase impedance, power factor, harmonic distortion and high potential must all be conducted on a regular schedule. This is an addition to regular dynamic motor current signature analysis to detect electromechanical rotor flaws and periodic static testing for early detection of stator flaws.
“World Class” maintenance programs include ultrasonic monitoring for leaks and electrical discharge coronas.
Condensers are monitored with a variety of means to identify leaks. Monitoring process variables are an important part of “World Class” maintenance. Symptoms of problems such as increasing internal clearances and distributed rotor damage (erosion, corrosion) are observed earlier in process measurements than mechanical vibration.
Proactive alignment and balancing programs are in effect to assure highest quality repairs and installation. Purchase and repair standards based on industry best practice are in place, broadly communicated, and enforced.
One of the program-of-the-year finalists made an interesting comment that vividly illustrates the benefits of condition directed maintenance — “it allows them to run the plant instead of the plant running them!”
MEASURABLE STANDARDS OF PERFORMANCE
“World Class” maintenance sets and tracks objective standards of performance. These include facility parameters such as heat rate, availability, and cost per unit of production. More specific parameters such as lost production cost, overtime hours and percentage of reactive maintenance are also tracked to measure maintenance effectiveness. The process is highly goal oriented. Performance indicators are assigned at the process and system level and tracked regularly to assure continuous improvement and provide early recognition of departures from required results.
SUMMARY
Achieving “World Class” maintenance requires a broad scope, attention to detail, accurate and representative measures of performance, efforts to achieve constant improvement and regular reports of performance. Many have achieved this level of success. All must recognize that remaining at this level is a moving target as expectations and standards of performance are continually elevated by the leaders.
Tags: Asset Management, equipment reliability, maintenance, maintenance practices, maintenance programs
The purpose of a predictive/condition based maintenance (PdM/CBM) program is to communicate information about the condition of the machinery under surveillance. The PdM/CBM report should include only information that helps the reader to clearly understand the results of the condition monitoring efforts. The report should include:
- An equipment status report including operating availability and component availability
- A priority work list including work pending, work in progress, and work completed
- Status definitions for satisfactory, marginal, and critical
- A summary of the operating status of each component to include fully operational, marginal, critical, and inoperable
Individual equipment status reports for equipment that is marginal or worse
The report serves two primary functions:
- It provides a valuable source of information for plant maintenance, operations, and engineering.
- It continually shows the impact of PdM/CBM on the plant to upper management. This line of communication justifies the program and allows for continued management support.
The reporting period is determined by the needs of the plant but a report should be prepared at least annually. It is important to note that the report should not contain any raw data collected from a diagnostic system. It should be concise and clear.
The following elements should be included in a PdM/CBM periodic report:
- Management summary – Provides a synopsis that highlights the activities performed during the reporting period. When possible, use photographs of actual plant conditions that illustrate successes.
- Equipment performance – Provides a list of equipment that predictive maintenance indicates is in an abnormal condition and has been placed on an alert or watch list.
- Windows® format and supporting documentation can be used to identify equipment condition. Also indicate in this section those pieces of equipment that have been removed from the alert or watch list.
- Information sharing – Provides a section to be used by predictive maintenance personnel to explain various aspects of the program or to share examples where assistance has been provided to other station departments.
- Cost-benefit – Provides cost savings that are attributed to predictive maintenance activities. Consider costs that were avoided because equipment replacement, maintenance labor hours, and purchase of replacement power were not needed.
- Continuous improvement and operating experience – Provides discussions on new technologies and training received by predictive maintenance personnel. This section could also be used to document any internal or external examples of operating experience factored into the predictive maintenance program.
Program Metrics
All nuclear plants have extensive goals and metrics to indicate effectiveness of plant programs and processes and to measure progress toward desired improvements. These metrics do not always relate to the effectiveness and progress of the PdM/CBM program itself. Therefore, it is useful to have a clearly defined set of performance measures that specifically relate to the PdM/CBM process.
A Best practice set of metrics is as follows:
- Focus on four important cost areas:
- Equipment reliability and unit availability
- Operations and maintenance costs
- Capital expenditures
- Thermal unit performance
- Maintenance task balance between unplanned corrective maintenance tasks (which are reactive), planned CM on run-to-failure equipment, repetitive PM tasks, and condition directed tasks, which are planned CM or PM tasks initiated as a result of decisions from the PdM/CBM process. Planned CM is defined as a situation where either the equipment has been predetermined as run-to-failure, or condition monitoring has detected degradation of the equipment and allowed time for proper planning and optimum scheduling of the task.
- Return on investment for PdM/CBM activities.
- Effectiveness in implementing the PdM/CBM process
PdM/CBM Key Performance Indicators
| Performance Parameter |
Indicator |
Target |
| Data Collection
|
Number of delinquent data collection PMs |
0 |
| Number of surveillance tests repeated due to
errant vibration data |
0 |
| Percentage data collection of total PdM/CBM
components – Motor Analysis Program |
100% |
| Percentage data collection of available PdM/CBM components – Motor Analysis Program |
100% |
| Percentage data collection of total PdM/CBM
components – Thermography Program |
95% |
| Percentage data collection of available PdM/CBM components – Thermography Program |
98% |
| Percentage data collection of total PdM/CBM
components – Vibration Program |
95% |
| Percentage data collection of available PdM/CBM components – Vibration Program |
98% |
| Data Analysis |
Number of occurrences of unidentified equipment degradation within PdM/CBM scope |
0 |
| Lube oil sample backlog |
80% ≤ 2 weeks
0% > 4 weeks |
| Equipment Reliability |
Percentage of undetected failures of PdM/CBM scope components |
<1.0%
|
Tags: CBM, Condition Based Maintenance, condition monitoring, PdM, Predictive Maintenance
1. Objective – provides an unbiased appraisal of a given condition or attribute
2. Countable/Measurable – can be trended objectively with time.
3. Controllable – assigned to the group that can direct the outcome of the condition being measured.
4. Meaningful – Reflect a condition that has a true impact on performance of the process
Tags: Key Performance Indicators, KPI, KPIs
Have you “Optimized” your PM program only to end up with more preventive maintenance tasks than you started with? – If you have, you are not alone; the majority of the organizations that we have talked with ended up with more to do not less and they seriously questioned the value of the new task in their PM program.
When optimizing a preventive maintenance program there are two key elements to keep in mind. The first is to effectively classify equipment and the second is to place an emphasis on predictive maintenance and equipment condition monitoring tasks. Effective classification of equipment allows the proper focus of resources for both the optimization and the conduct of the Preventive Maintenance program. Effective equipment classification should be based upon a clear understanding of the probability of equipment failure and the consequences of that failure, so as to minimize the risk to safety, production, and operating budgets. Historically many plants have used a 2 tier system for classifying equipment. The equipment was classified as either critical or non-critical with all safety related equipment having a default classification as critical. In theory the most plants in the industry now uses a minimum 3 or 4 tiered system. However, many plants still seem to default to the 2 tier system, “critical and everything else”, due to an excessive number of PMs. When optimizing a PM program a six tiered priority system seems to provide enough granularity to effectively allocate resources, the exact number should be determined by your plant. A caution should be noted here, use of a large number of tires in the classification systems risks the chance that the system becomes too complicated to be useful. In that case the organization ends up defaulting back to a 2 tiered system. The following is an example of an equipment classification system for consideration:
- Safety Critical – functional failure could result in significant injury to plant personnel or the failure of a nuclear safety function
- Production Critical – functional failure could result in all or major loss of production capability
- Safety Important – functional failure require significant effort to put in place barriers to protect personnel
- Production Important – functional failure could result in a significant loss of production capability
- Minor – functional failure has little or no impact to production or safety however it is financial prudent to perform work prior to failure
- Run-to-Failure
Adhering to the classification system that is developed is important and will take organizational discipline.
Most of us are familiar with the “bathtub curve” that was developed out of equipment reliability studies performed in the 1950’s. This curve has us make the assumption that as a whole our plant equipment has some period of infant mortality, followed by a period where the probability of equipment failure is fairly flat and then close to the end of the equipments usefully life the probability of equipment failure increases. If we follow this assumption, our natural tendency then is to develop maintenance tasks timed to be performed just before a piece of equipment would fail to perform its intended function; thereby allowing for the longest period of useful life and the lowest probability of production interruptions due to equipment functional failures. If equipment failures did occur, the “bathtub curve” might also draw us to the conclusion that there were either an insufficient number of PMs or that their frequency of the existing PMs was insufficient to prevent the equipment failure. This is how most early PM program analysis was performed and PM programs grew to be too large to effectively manage.
During the development and refinement of Reliability Centered Maintenance (RCM) analysis methodology Stanley Nowlan and Howard Heaps broke down the “bathtub curve” into six separate curves. Their studies showed that only 11% of equipment failures followed an age related degradation path while 89% of equipment failures were random in nature.
Nowlan & Heap
While some reliability experts may argue over the exact percentages of age related failures versus random failures the general consensus is that random failures far outnumber age related failures in our plants. So why then, are the majority of plants maintenance strategies predominately comprised of time based maintenance (preventive maintenance) tasks? If the majority of equipment functional failures in our plants are random in nature, then shouldn’t the majority of maintenance strategy tasks be designed to detect the onset of those random failures?
Predictive Maintenance and Condition Monitoring (or CBM) tasks are designed to identify degrading conditions in equipment prior to functional failure. The appropriate PdM/CBM dependent on the type of equipment and failure modes associated with the equipment and its operating environment. The frequency at which PdM/CBM tasks should be performed should be based upon a number of factors including; the risks (probability and consequence) associated with functional failure, the availability of operating conditions needed to collect data, the ability of the monitoring technique(s) being applied to detect the onset of degradation, the skill of the technicians collecting and analyzing the data, and the rate of degradation of the of the failure modes being evaluated.
So in summary, an effective PM optimization effort, along with all the other considerations management may place on the effort, must stress the accurate classification of the equipment and provide a focused effort on replacing time based tasks with PdM/CBM tasks.
Tags: Maintenance Basis, PM, PM Templates, Preventive Maintenance, RCM, Reliability Basis, Reliability Centered Maintenance
It has been more than two decades since predictive maintenance and condition monitoring were introduced in the electric power industry. Since then, the industry as a whole has learned a lot about equipment failures, the mechanisms that induce those failures, and how to identify impending failures. The tools that are available today cover more than just the “big three technologies” (vibration, oil, and infrared analysis).
Yet with all that is available to us as an industry many organizations still struggle to take full advantage of condition monitoring and predictive maintenance. Or, may because of all the information and technology that is available to us we struggle to get the full value of our programs.
Being successful at implementing Predictive/Condition Based Maintenance requires that an organization be successful in three areas: People – train and educate our plant’s staff (not just the PdM/CBM staff) to understand the importance of PdM/CBM to the success of the organization; Technologies – select the right technology for the right application and understand what the information being provided is telling us about the health of our equipment and plants; and Processes – designing and implementing PdM/CBM processes that are integral to our daily work and provide actionable information to the work management efforts.
The Electric Power Research Institute (EPRI) identified “14 Key Elements” of successful predictive/condition based maintenance programs. These “14 Key Elements” include:
1. Task Technical Basis – should provide a clear understanding of what potential failure mechanisms are being “monitored for”, the impact of those failure mechanisms on the equipment and the plant, and the likely hood of their occurrence.
2. Technology Application – should include procedures and guidelines for application. Each technology being applied should be well understood and consistently applied.
3. Process Flow Definition – should be well defined including all interfaces with engineering groups, work management, maintenance, and operations.
4. Program Leadership and Coordination – should include good visibility within the organization for the PdM/CBM leadership. That leadership should promote the use of and the benefits of PdM/CBM.
5. Organization, Roles, and Responsibilities – should include real accountability and evidence that the responsibilities are being carried out as defined by the process.
6. Information Management and Communications – personnel should correlate PdM/CBM data with other forms of plant information to provide a clear picture of the health of equipment. This information should be communicated to other groups efficiently to support timely actions.
7. Equipment Condition Assessment and Decision Making – condition data should be trended, analyzed, integrated and a report generated on anomalies for equipment owners and management to review. It should be clear who has the responsibility for making decisions on equipment based upon its health.
8. Training and Qualifications – the users of the information developed by PdM/CBM should have a basic understanding of the techniques. The PdM/CBM personnel should be well trained and certified and should be participating with their pier in the industry.
9. CBM/PdM Work Prioritization and Scheduling – data collection tasks should be well defined, prioritized and scheduled in the work management process. The plant should ensure that data is collected consistent with the program requirements.
10. Work Closeout and Maintenance Feedback – should include documentation of as found conditions; it should be timely and be provided to the PdM/CBM organization, maintenance and the equipment owners.
11. Goals and Performance Metrics – should be part of the integrated metrics used by the plant. They should be well developed and consistent with the overall goals of the organization.
12. Calculations of Cost-Benefits and Return on Investment – should include both a probabilistic approach to cost avoidance along with and the real budget associated with running the program. Management should understand and support the analysis process and the values used in the analysis.
13. Internal Customer Satisfaction – internal customers should be identified and their input as to how the PdM/CBM process could be more useful to them should be solicited.
14. Continuous Improvement – industry and technologies should be reviewed on a regular basis to incorporate lessons learned and new thought process so as to make the PdM/CBM process more effective.
When looking to enhance or revitalize your PdM/CBM process create a clear definition of your ideal organization with respect to the above 14 Key Elements; once this has been complete an assessment of where your organization is performing in each of needs to be performed. With an understanding of where your organization needs to be and where it is today, an organizational change plan can then be developed to effectively move your organization forward.
Tags: CBM, Condition Based Maintenance, condition monitoring, PdM, Predictive Maintenance
