What's your maintenance strategy?

In this guest blog from Daniel Penn Associates, common maintenance strategies used by plant professionals are highlighted and expanded upon.

08/01/2014


Maintenance strategy doesn't enter our non-technical brains unless it directly affects our productivity and well-being. You change the oil in your car's engine (that's preventive maintenance) to keep it running so the engine doesn't seize and you’re not late for work. However, if you've ignored your car's transmission and it drops out on the way to a new business presentation, you have no choice but to stop at a garage for some reactive maintenance. (The other 'reaction' will be losing that new business opportunity, but I digress.)

Maintenance professionals who have hundreds of millions of dollars riding on consistent production and on-time delivery know there is much more to the story. The maintenance strategy they choose can have significant financial consequences.

Five methods, various uses

Each of the five basic maintenance strategies — preventive (aka planned), reactive, predictive, condition based, and reliability based —has its own distinguishing features and optimal applications.

  • Preventive (aka Planned) Maintenance (PM). This is maintenance activity that takes place before something breaks so you don’t incur equipment downtime or lost product. It is almost always cheaper to do this than to wait for failure.

  • Reactive Maintenance. Just as it sounds, this is maintenance activity that reacts to equipment failure after it occurs. However, sometimes waiting for equipment to fail is the best thing to do, as I’ll explain below.

  • Predictive Maintenance (PdM) is maintenance based on specific information about the equipment that is a reliable predictor of imminent failure. Examples include oil analysis, vibration analysis, and thermal analysis.

  • Condition Based Maintenance (CBM) – this is often used synonymously with predictive maintenance The distinction? CBM is driven from real-time data gathered from sensors and other devices that measure specific conditions against known parameters of failure so that action can be taken in advance.

  • Reliability Centered Maintenance (RCM) has a much broader scope, often incorporating all of the other strategies. RCM has been referred to as a process to establish the safe minimum levels of maintenance. RCM begins with answering seven questions about the equipment:

    • 1) What are the functions and associated performance standards of the asset in its present operating context?
    • 2) In what ways does it fail to fulfill its functions?
    • 3) What causes each functional failure?
    • 4) What happens when each failure occurs?
    • 5) In what way does each failure matter?
    • 6) What can be done to prevent each failure?
    • 7) What should be done if a suitable preventive task cannot be found?

RCM is a complete engineering approach designed to do whatever it takes to promote the greatest level of equipment reliability with the least investment of maintenance cost.

Decisions, decisions.

Some general guidelines for choosing a maintenance strategy:

Preventive Maintenance (PM): You’ll need to develop detailed job plans that spell out the maintenance tasks and the time intervals for each to keep the equipment up and running. You also should have a means to capture the conditions found at each inspection. This is usually done with a PM work order and captured by the computerized maintenance management system (CMMS) for later analysis.

Reactive Maintenance (RM) only works if the equipment cannot be easily / cheaply repaired. If it is cheaper to replace than to repair, use reactive maintenance and then make sure you have a ready supply available. A common example is an electrical motor rated at 5hp or less.

Predictive Maintenance (PdM) requires an investment either in analytical equipment and user training or contractors to do the analysis. The decision depends on your specific situation.

Condition Based Maintenance (CBM) is considered a good strategy overall (again, depending on your type of equipment) but it is also good way to minimize energy expense. CBM usually requires an investment in a remote data gathering system and user training.

Reliability Centered Maintenance (RCM) is a great maintenance strategy and considered the most cost effective overall. As we mentioned, RCM may encompass all of the other strategies depending on the equipment component and the available resources.

Plant Engineering recently gathered a lot of information about how maintenance professionals feel about these strategies. Take look at the Plant Engineering 2014 Maintenance Report to see what your peers have to say.

How have you resolved the issue of which maintenance strategy to employ in one or more scenarios at your facility? Please share your insights and experience, and thanks for visiting!

Steve Mueller is Director of Commercial Operations for Daniel Penn Associates. As such he is responsible for project development, management and the delivery of results for our private sector clients.  Steve has over 30 years consulting experience.



Top Plant
The Top Plant program honors outstanding manufacturing facilities in North America. View the 2017 Top Plant.
Product of the Year
The Product of the Year program recognizes products newly released in the manufacturing industries.
System Integrator of the Year
Each year, a panel of Control Engineering and Plant Engineering editors and industry expert judges select the System Integrator of the Year Award winners in three categories.
February 2018
2017 Product of the Year winners, retrofitting a press, IMTS and Hannover Messe preview, natural refrigerants, testing steam traps
March 2018
SCCR, 2018 Maintenance study, and VFDs in a washdown environment.
Jan/Feb 2018
Welding ergonomics, 2017 Salary Survey, and surge protection
April 2018
ROVs, rigs, and the real time; wellsite valve manifolds; AI on a chip; analytics use for pipelines
February 2018
Focus on power systems, process safety, electrical and power systems, edge computing in the oil & gas industry
December 2017
Product of the Year winners, Pattern recognition, Engineering analytics, Revitalize older pump installations
April 2018
Implementing a DCS, stepper motors, intelligent motion control, remote monitoring of irrigation systems
February 2018
Setting internal automation standards
December 2017
PID controllers, Solar-powered SCADA, Using 80 GHz radar sensors

Annual Salary Survey

Before the calendar turned, 2016 already had the makings of a pivotal year for manufacturing, and for the world.

There were the big events for the year, including the United States as Partner Country at Hannover Messe in April and the 2016 International Manufacturing Technology Show in Chicago in September. There's also the matter of the U.S. presidential elections in November, which promise to shape policy in manufacturing for years to come.

But the year started with global economic turmoil, as a slowdown in Chinese manufacturing triggered a worldwide stock hiccup that sent values plummeting. The continued plunge in world oil prices has resulted in a slowdown in exploration and, by extension, the manufacture of exploration equipment.

Read more: 2015 Salary Survey

The Maintenance and Reliability Coach's blog
Maintenance and reliability tips and best practices from the maintenance and reliability coaches at Allied Reliability Group.
One Voice for Manufacturing
The One Voice for Manufacturing blog reports on federal public policy issues impacting the manufacturing sector. One Voice is a joint effort by the National Tooling and Machining...
The Maintenance and Reliability Professionals Blog
The Society for Maintenance and Reliability Professionals an organization devoted...
Machine Safety
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
Research Analyst Blog
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.
Marshall on Maintenance
Maintenance is not optional in manufacturing. It’s a profit center, driving productivity and uptime while reducing overall repair costs.
Lachance on CMMS
The Lachance on CMMS blog is about current maintenance topics. Blogger Paul Lachance is president and chief technology officer for Smartware Group.
Maintenance & Safety
The maintenance journey has been a long, slow trek for most manufacturers and has gone from preventive maintenance to predictive maintenance.
Industrial Analytics
This digital report explains how plant engineers and subject matter experts (SME) need support for time series data and its many challenges.
IIoT: Operations & IT
This digital report will explore several aspects of how IIoT will transform manufacturing in the coming years.
Randy Steele
Maintenance Manager; California Oils Corp.
Matthew J. Woo, PE, RCDD, LEED AP BD+C
Associate, Electrical Engineering; Wood Harbinger
Randy Oliver
Control Systems Engineer; Robert Bosch Corp.
Data Centers: Impacts of Climate and Cooling Technology
This course focuses on climate analysis, appropriateness of cooling system selection, and combining cooling systems.
Safety First: Arc Flash 101
This course will help identify and reveal electrical hazards and identify the solutions to implementing and maintaining a safe work environment.
Critical Power: Hospital Electrical Systems
This course explains how maintaining power and communication systems through emergency power-generation systems is critical.
click me