Planned Maintenance and Key Performance Indicators (KPI)


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What should a company uses for a benchmark when scheduling work orders? At what point or timeframe do you cut off the schedule and call it "unscheduled"?

Answers or Advice:

  • Scheduling may simply be based on the days of the work week. Here's an example from: Youe maintenance planners meet with their production counterparts on Thursday's to review the backlog for that area. Together, they select the workorders to be scheduled for the following week. They have until Friday evening to enter the target start date for those workorders into the CMMS. The planners create a custom table in your CMMS system into which these records are loaded. You may use the data in this table for compliance reporting. (This is a way to "lock" the schedule since the dates can't be changed in the custom table).

  • While designing the KPI and setting up the (% deviation allowable) be sure that the average exception is in the range of 30-40% and not more. Otherwise, nobody may be intrested in the KPI. Once the lower deviation is achieved lower the deviation level to next level. Also make sure that you are not over-maintaing the plant equipment.

  • If your planners can't handle incorporating additional work less than 12, 24 or 36 hours before a shift, that should be the cutoff time. It should also depend on how much is already scheduled for that particular shift, in other words you can't really come up with "one rule fits all". Additionally, it's recommend that people perform proper RCM (reliability-centered maintenance) analyses on their plant, so they know exactly what needs to be done and how often. It is also recommended that people respond to asset performance deterioration as soon as possible. If not, you get substandard production in either quantity or quality. If you address deterioration, you should only get very few, perhaps random, failures. That means that the overwhelming majority of your work is planned. So, why should anybody come up with additional work 10 or 12 hours before a new shift? Perhaps the only reason that your organization responds is to breakdowns. So this may be a reason to look into how to improve asset management, rather than worrying whether a cut-off time should be 20 or 16 hours before a shift.

  • Try not to completely follow another company or organization's example. Determine what is possible at your company. If your planners can't handle incorporating additional work less than 12, 24 or 36 hours before a shift, then that should be the cutoff time. It should also depend on how much is already scheduled for that particular shift. In other words, you can't really come up with "one size fits all" strategy.

    One industrial manager for a major petroleum company noted that she always recommends that people perform proper RCM (reliability-centered maintenance) analyses on their plant, so they know exactly what needs to be done and at which frequency. She also recommends that people respond to asset-performance deterioration ASAP. If not, she noted, you get substandard production in either quantity or quality. If you address deterioration, you should only get very few, perhaps random, failures. This means that the overwhelming majority of your work is planned. So, why should anybody come up with any additional work 10, or 12 hours before a new shift? She adds that the only reason that some organizations respond to breakdowns. Hence this is perhaps a justified reason to look into how to improve asset management, rather than worrying whether a cut-off time should be 20 or 16 hours before a shift.

What percentage corrective and predictive maintenance should a company strive for?

Answers or Advice:

  • Some feel KPI's and benchmarks may not be such a good idea, as people think that they should achieve certain published figures (percentages, etc).

    A certain Asian factory with several plastic molding machines rarely used all of them (the machines) at once. If one failed, they took the mold and placed it on another, then repaired the failed machine. This factory doesn't seem to need any preventive nor predictive maintenance. Imagine if they were going to strive for 50% condition-based, 45% time-based and 5% breakdown. Would that save them money?

    So beware of KPIs that somebody else may have achieved. Don't believe that trying to copy those will guarantee that you will be better off.

    A good alternative would be to calculate the overall equipment effectiveness factor, which is based on six major losses that all directly affect your profit. Measure where you are, then analyze which loss contribute mosts, do something about it and keep improving. Benchmark first against yourself and be guided by what measuring those losses tell you. Eventually you may try and compare against your competitors, but we doubt whether you could get hold of their figures. Your competitors are the ones to worry about, not published figures from one particular plant in Taiwan or Ireland, making something totally different to what you do.

  • The maintenance plan does not stop -- it's a program of activities that constantly needs to be updated and managed. You are not going to ignore a critical, unexpected failure just because it's not on the plan. It is all about risk, and jobs are prioritized and get done based on the consequences of the issue to be addressed. If the job has to be done, put it on the due list and manage it from there to allow proper assessment of resources and impact.

    Some things to look out for:

    1. Align you resources (per trade), to your current workload scenario with some safety margin. This implies that you must acknowledge any current trend in re-active workload and allow time for this on top of your pro-active workload otherwise you pro-active effort is going to suffer. If the reactive work does not manifest, you have your backlog then to help make up your utilization of resources.
    2. Establish risk-evaluation rules on due and overdue management. As inspection and service intervals are associated with specific PF Intervals, a weekly going overdue by one week, is far more critical than a bi-monthly becoming overdue in three weeks when evaluating the straight theoretical principals. You should have specific overdue-management rules to prevent the creation of failures.
    3. Structure your tasks types to allow a very clear differentiation between proactive and reactive work. Proactive work here meaning that the work is executed through standard tasks from your CMMS, which were established as part of an evaluation process where they were found to be technically feasible, safe and environmentally friendly, and cost-effective. These are typically your Condition-based Maintenance Task sets (Scheduled Condition-Monitoring Task and Dormant Follow-up Corrective Task), Usage-Based Maintenance Tasks, and Run-to-Failure Task sets (Scheduled-Failure Finding Task and Dormant Follow-up Corrective Task).
    4. Structure you Work-In-Progress/Due- and Overdue-Work Lists to effectively support planning on resources, presenting the impact of the individual tasks on production availability, spares issues, trade allocation, PF Intervals, criticality, overdue period etc.

    The percentage of work done (based on number of, hours, costs), through standard tasks as opposed to newly created work orders, is a good measure of the maturity of maintenance programs. It is often more usable than other ratios due to the huge margin of interpretation and poorly structured task types which does not allow effective analysis. For most industrial companies, if this percentage is less than 50%, you are very reactive, above 60%, it starting to look up and the upward trend should be the target. It is quite an interesting discussion about whether 100% is achievable. Theoretically it's .

    There is no short answer in maintenance...

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