Best Practices: Implementing Preventive Maintenance Prioritization

Why does Preventive Maintenance Activities require prioritization?

Objective of Preventive Maintenance program is to minimize unplanned failures, improve equipment availability, reliability and safety, deliver superior performance, and extend equipment life.  Preventive Maintenance programs are designed to meet these objectives in a consistent and efficient manner. 

Preventive Maintenance planning is done at the plant level with numerous assets and the schedules are defined for a long horizon (3 or 5 years).   PM Schedules run as per the frequency set in and generate the quarterly, monthly or weekly schedules.  For a given period (say month), numerous preventive maintenance schedules will be generated and includes combinations of equipment, PM frequency etc.   All the PM Work Orders are generated with same priority.

Availability and  performance of equipment and production lines are highly impacted  by the execution of preventive maintenance activities.  Resources available with the organization is always limited and hence there is a need for prioritization.  Prioritization of these preventive maintenance work orders systematically and based on pre-defined criteria will help in improving maintenance efficiency and optimization of resources. 


What are the factors that should be considered in PM Prioritization?

The factors that need to be considered while prioritizing Preventive Maintenance Work Orders include

1.  Equipment Criticality

Not all equipment are equal.  In any production line certain equipment are more critical than others.  Unplanned downtime of such equipment impact production line disproportionately higher and maintenance of such critical equipment should be considered on higher priority.

2.  Breakdown Since Last PM Work Order:

Despite timely Preventive Maintenance, equipment do fail unexpectedly.  Analyzing cause of the failure and strengthening the PM tasks to avoid their recurrence is a best practice.  PM prioritization based on the traceability of failure phenomena to the mitigating PM Schedule and task can be a factor in prioritization.

3.  Type of Preventive Maintenance:

Scope of preventive maintenance activities executed vary depending on the nature of PM schedules (Time based or Condition based) and the frequency (Annual Vs Quarterly).   Preventive maintenance schedules that are based on  yearly frequency or other such longer durations tend to be more comprehensive in scope and include a variety of inspection and mitigation tasks.   Condition Monitoring schedules tend to focus on a specific problem in a deeper and focused manner.  Thus, type of Preventive Maintenance is an important consideration in determining priority.

4.   Days since Last PM > MTBF:

MTBF indicates the expected run time of the equipment before failure. MTBF can also be calculated in a more granular way, by failure mode.  Re-prioritization of PM activity for an equipment can be considered when the elapsed time is more than the MTBF or when the MTBF by failure mode is above the threshold.

5.  Risk score / Ageing Analysis:

Certain equipment are prone to more failures due to operating conditions or other factors.  Age of the equipment affect the incidence of breakdowns.  Composite equipment risk scores computed from equipment age, health, failure history, performance etc. can be considered as a factor for prioritization.

6.  Residual Spares Life is trending to Zero:

Spares have a definite life and spares failure result in downtime.  Prioritization can also be done where the spares are nearing their end of life  (measured in calendar days or run hours) are given a higher priority.

7.  Condition Monitoring parameters:

Condition Monitoring of usage and critical performance parameters can give insights on equipment performance and early symptoms of deterioration.  Providing insights on the usage and critical parameters status and estimates on when next condition monitoring schedules will be triggered can also help in prioritization.  

8.  Last PM Missed / Incomplete Tasks:

Preventive Maintenance activities are scheduled to avoid downtime.  However, due to production schedules and other real life situations, preventive maintenance may get delayed, cancelled or completed partially.   Such missed out PM activities should be given additional priority in the next cycle.

9.  Peer Class CAPA:

Root cause analysis of breakdowns can result in Corrective Actions and Preventive Actions (CAPA).  Extending the same CAPA activities to other peer class equipment via horizontal deployment is a best practice.  Such CAPA actions can be scheduled and taken up together with the subsequent Preventive Maintenance activities and their scope and criticality can  impact prioritization as well.

How do we implement PM Prioritization?

PM Prioritization is often done heuristically.  While such methods take into account the experience, expertise and judgement of the practitioners, they are highly personal and not scalable.  A systematic way to quantify the above factors and arriving at a composite score for PM Prioritization can result in a scientific and standardized process, that is more scalable across different plants and timeframes.

 PM Prioritization Score can be       computed as

        PM Prioritization Score = g(f1, f2, .. fn)

         where g is the computational function and fi  is the influencing factor.

Implementation of  Computerized Maintenance Management System (CMMS) can help in preventive maintenance prioritization.  CMMS platform keeps all the equipment and failure history, maintenance metrics, connect and retrieve condition monitoring parameters etc. and act as the central repository.  Building the PM prioritization scoring and process on top of CMMS can help in execution and standardization across plants. 


How can MaintWiz help in PM Planning and Prioritization?

MaintWiz industry 4.0 CMMS provides comprehensive tools to set up preventive maintenance schedules and tasks effectively.  It supports Time Based, Condition Based and Event Based Maintenance.  Library based schedules and tasks help in propagating the revised schedules and tasks to all peer class assets effectively.

It has many planning tools that can help in forecasting and visualizing the upcoming PM activities.  Visualizations based on equipment calendar, tools calendar, resource loading, spares requirement and vendor coordination can help derive a holistic view, prioritize  and plan the activities better.

MaintWiz holds the complete equipment history including OEM specifications and recommended schedules, past failures and failure modes, calculated metrics like MTTR and MTBF.  It can connect with PLCs and other control systems to ingest condition monitoring data automatically.   It can support advanced computations, derived parameters and PM Prioritization score and other metrics. 

It hosts a powerful rules engine under the hood which helps in configuring business rules based on condition monitoring values, calculated values and workflows, to trigger work orders and other maintenance activities.  MaintWiz CMMS institutionalizes the processes and best practices, and makes them available as contextual and intelligent decision support tools.

MaintWiz has many more powerful features that can super-charge your maintenance organization.  It simplifies technology and is very easy-to-implement and use. 

Contact us or schedule an Online Demo of MaintWiz CMMS, to revitalize your Maintenance.