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Detective Maintenance versus Predictive Maintenance

Detective Maintenance versus Predictive Maintenance

Detective Maintenance

Detective MaintenanceDetective MaintenanceTerrence O'Hanlon

If you were to step into Mr. Peabody's Way-Back machine and be there for the original publication of Reliability-centered Maintenance by Nolan and Heap more than 40 years ago - the pure version- not reinterpreted, there a few BIG ideas that should have been kept "pure" or in their original state.

In my opinion one of these concepts, phrases, approaches, work types, called Predictive Maintenance did NOT originate in Nolan and Heap and has caused massive confusion and may have actually hindered the advance of reliability in many cases.

Nolan and Heap explain so clearly I am not sure why we changed.

Please follow my logic:

Argument 1:

A potential failure (point C on the P-F curve below) is an identifiable physical condition which indicates that a functional failure is imminent

Original P to F Curve Reliability-centered Maintenance [Nowlan and Heap]

Argument 2:

There are essentially only four types of tasks in a scheduled maintenance program that maintenance personnel could be asked to do and the first one to "Inspect an item to detect a potential failure - a potential failure is an identifiable physical condition which indicates that a functional failure is imminent"

If I apply that to modern Vibration Analysis, Infrared Thermal analysis, Ultrasound, Fluid Analysis or any of the other Asset Condition Management technologies - that seems well within their capabilities. To detect a potential failure (an identifiable physical condition) which indicates that a functional failure is definitely going to happen. No prediction, no guessing.

Argument 3:

The definitions

Detect - discover or identify the presence or existence of.

Predict - say or estimate that (a specified thing) will happen in the future or will be a consequence of something.

I would rather detect than predict.

Do you speak Reliability?Do you speak Reliability?

So we started using Asset Condition Management as the term for several reasons:

  • The objectives are much higher per ISO-55001 and aligned to the organizational objectives through line of sight
  • We do not want to simply monitor the condition of the asset - we want to manage the condition of the asset.
  • We think that prediction or predictive sets up unrealistic expectations
  • The term predictive is not found in Nolan and Heap's Reliability Centered Maintenance
  • We want to accomplish more than predicting maintenance

You can follow some of the very interesting LinkedIn discussions that have led to this post here:

No Predictive Maintenance 01

No Predictive Maintenance 02

No Predictive Maintenance 03

No Predictive Maintenance 04

No Predictive Maintenance 05

No Predictive Maintenance 06

No Predictive Maintenance 07 (IoT Version)

No Predictive Maintenance 08 (Bearing version)

No Predictive Maintenance 09 (CEO)

No Predictive Maintenance 10

Michael Whittaker added the point that there are are accurate "predictive" tools for prognostics so I found this description. It is not a topic I am well versed in but I will begin researching

"Progresses in prognostic maintenance technologies offer opportunities to aid the asset owner in optimal maintenance and life cycle decision making, e.g. replacement or life-time extension of physical assets. Using accurate lifetime predictions is critical for ensuring just-in-time maintenance."

Publishers note:

Q : Why do I rally against the words "predictive maintenance?

A1: Because they are simply a marketing term - not a technical term.

A2: Marketing/sales created all kinds of crazy words and concepts around CMMS and EAM in the early days and I just sat and watched. It ended up creating 70%-80% software project failure rates because the context of those words, maintenance approaches and maturity descriptions were not possible. I do not plan to "watch" this time. Digitalization has too much potential for competitive advantage, safety, sustainability, quality, cost, profit, retention etc...

The language. should reflect the reality of the asset owner/operators (customers) - NOT the vendors (sellers).

Terrence O'Hanlon

Terrence O’Hanlon, CMRP, and CEO of® and Publisher for Uptime® Magazine, is an asset management leader, specializing in reliability and operational excellence. He is a popular keynote presenter and is the coauthor of the book, 10 Rights of Asset Management: Achieve Reliability, Asset Performance and Operational Excellence.

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