Maintenance Optimization: Optimize Planned & Preventive Maint.

What is planned maintenance optimization?

Planned Maintenance Optimization (PMO) is a method of improving maintenance strategies based on existing preventive maintenance (PM) routines and available failure history.


While most companies have identified the need for a preventive maintenance (PM) program, the effective execution of such maintenance activities can be challenging given the everyday demands of a facility. Unseen circumstances that require urgent attention can easily derail planned activities and can potentially disrupt a smoothly running plant.

While alternatives such as reliability centered maintenance (RCM) addresses some of the factors that make PM a cost- and labor-intensive process, coming up with a robust RCM strategy may take long periods of time.

PMO provides a method through which maintenance activities are carried out more efficiently. By performing PMO, a new maintenance strategy is derived from existing PM tasks. Given the existing tasks, modifications on the schedule and frequency of the routines are done based on the failure history of the equipment. With a relatively shorter time to develop, the resulting strategy can be similar to performing RCM.

The three phases of PMO

The PMO process can be summarized in three phases:

Data collection

Any attempt at optimization starts with good, reliable data. Data on equipment performance, particularly on failure history over time, must be collected. A minimum time period must be set to ensure that enough insight is obtained from the data. Tools such as a CMMS program can make this process easier and more accurate.

Data analysis, review, and recommendations

The collected data must be analyzed to identify which equipment is the most critical. Some points to consider are criticality to the plant’s operations, cost to repair, MTBF, and MTR.

The information gathered from analyzing the data must then be reviewed against existing PM routines. Some key points to review are: 1) whether the PM routines are scheduled correctly to align with the MTBF and MTR data points, and 2) whether failure points are within acceptable tolerances set by original equipment manufacturer (OEM) specifications or industry standards. Any substantial deviations from such checks can be a source of improvement from a maintenance standpoint.

Based on the review, recommendations on modifications for the PM tasks should be made. Schedules and frequencies of activities need to be optimized to meet MTBF and MTR constraints. Any missing maintenance activities, as well as redundancies in tasks, need to be addressed accordingly.

Agreement and execution

Agreed action items must be delegated properly. Identified task owners should be accountable for any required action and monitored for progress. Note that the PMO process is a continuous effort and reviews should be done habitually.

Benefits of applying PMO

Regular maintenance activities are clearly a key part in ensuring a plant’s reliability. But PMO further increases the benefits of maintenance activities by showing substantial reductions in costs.

In the laboratory and life sciences industry, a PMO program is estimated to reduce overall maintenance costs by around 25%. Payback periods of investing in a PMO strategy are estimated at around 12 to 24 months, just considering the measured savings from maintenance costs.

Aside from the improvements in uptime and reliability that come with a robust maintenance strategy, PMO methods enable company resources to be spent more wisely without sacrificing the quality of execution of maintenance tasks.

How can I optimize an existing preventive maintenance plan?

There are a few different approaches to preventive maintenance optimization (PMO).

One of the easiest methods is simply asking your technicians. Odds are, they’ve been performing the same PM tasks for a while, and they’d probably have some insight on what could be done better. If any of their tasks seems irrelevant, they’ll let you know if you ask.

While this is the simplest way to track down superfluous PM tasks, it’s not the most precise, and it is pretty subjective. That said, it’s easy to do when you’re just starting to optimize PM in your facility.

The next way is a bit more precise, though it is based on some industry assumptions. A few decades ago, a maintenance and engineering manager named John Day, Jr. proposed the 6:1 rule. This rule asserts that for every 6 PM tasks you perform, you should be finding one corrective maintenance task.

This rule isn’t perfect, but it can give you a good starting point for optimizing your PM. If you’re performing more than six PMs for each CM, you may want to scale back a bit, but only after doing some research. if it looks like your PM:CM ratio is too high, I’d advise analyzing the types of failures you’re preventing. If they don’t pose too much of a threat, scaling back relevant PM tasks could be a good idea.

On the other hand, if you have more CM than the ratio dictates, you might be facing one of these two possibilities:

  1. You’re not doing enough PM.
  2. You’re doing too much of the wrong PM.

Again, some extra analysis will help you make the right choice here. Do some digging into the kinds of preventive maintenance tasks you’re performing and see if those are addressing the right issues. If they are, your PM timing or quantity may be off. If they’re not, then you’ll want to scale those back and replace them with more relevant tasks.


A similar approach involves tracking hours performed on PM and emergency maintenance for a single asset. If you have more emergency repair hours than PM hours, you’ve probably got a problem and will want to do some analysis on the root cause.These last two approaches give you more precision, but they do take more planning, so keep that in mind when you start streamlining your PM.


Maintenance activities, particularly PM activities, are already proven concepts that increase the overall performance of a plant. With continuous practice, PMO is a tool that can help execute PM activities more efficiently and effectively.

Want to keep reading?

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