Try this experiment – ask five or more people at random from within your company whether the tasks below are part of a preventive maintenance program:.
- Removing the oil dipstick each month and replacing the oil when its color is too dark
- Going around the plant on a routine inspection to check out fire and safety equipment, exit lights, etc., and replacing an exit light bulb that was observed to be out
- Replacing a filter every six months regardless of how clean or dirty it is
- Replacing a battery when the indicator light is on
- Adjusting aging equipment to run slower in order to lower the likelihood of equipment failure
- Repairing a redundant motor that failed to prevent overall system failure.
Then ask them how they would define the term “preventive maintenance” or “PM” and see if it is consistent with their earlier responses. Now probe on the following:
- Isn’t #1 condition-based maintenance or predictive maintenance based on the condition of the oil on the dipstick?
- Isn’t #2 run-to-failure or corrective maintenance because the exit bulb had failed and was replaced when discovered? In fact, is an inspection really “maintenance” if nothing has been done to the asset except observe it? In my view, inspections, measurements and tests are a means of determining if maintenance is required, where maintenance is defined as an adjustment, a repair, or a replacement.
- Isn’t #3 unnecessary if the filter is clean? What if the filter is so dirty that the asset requires repair – is this still preventive maintenance?
- Isn’t #4 considered a battery failure if the indicator light means the battery is inoperable or predictive maintenance if the indicator light means the battery is about to fail?
- Isn’t #5 more of an operational decision and not maintenance at all if all you are doing is operating the equipment at a lower speed to slow its deterioration?
- Isn’t #6 run-to-failure or corrective maintenance? In my view, the act of having redundant parts, components, or assets, is not really part of a PM program.
I have found that most people at all levels in the organization would consider most if not all six tasks listed above as legitimate parts of a PM program. When asked the definition of preventive maintenance, many would say variations on the theme of “PM is maintenance to prevent asset failure.” It is hard for people to avoid using the same two terms they are defining in their responses, so dig deeper and ask them to define “maintenance” and/or “prevent.” Not surprisingly, even further inconsistencies tend to emerge. Now throw in terms such as “predictive maintenance,” “condition monitoring,” and so on, and you just add fuel to the fire.
I have tried variations of this experiment many times over the years, and it never ceases to amaze me the wide range of responses, the high level of confusion, and the inconsistencies exhibited. You will also find similar inconsistencies in the definition of many other terms, such as those below. Can you differentiate among the terms in each group? Are your definitions similar to mine or to your colleagues’?
- Problem code, symptom code, fault code, cause code, root cause code, failure code, delay code, remedy code, solution code and action code
For example, if a pipe lying beside other pipes in unusually wet soil conditions has corroded prematurely and is leaking oil, is the problem code “surface oil detected,” “oil leak,”, “pipe leak,” “corroded pipe,” “excessively wet soil,” or other? I use “problem code” and “symptom code” interchangeably and define them to be how the issue appears to the initial observer who is usually not a maintainer. In the example above, if homeowners call into a pipeline company with their observation, the problem would be recorded as “surface oil detected” because we do not yet know if there is a pipe leak. When the maintainer goes out to investigate, a cause code might be recorded as “corroded pipe” against the appropriate pipe asset. Failure analysis by engineers may determine the root cause to be unusually high moisture content in the soil, in which case the “failure code” (or root cause code) would be “excessively wet soil.”
- Computerized maintenance management system (CMMS) versus enterprise asset management (EAM)
Suppliers of these software packages like to define EAM systems as more suitable for managing equipment across a large company. However, in my view and many users’ view, this is also what a CMMS does. Most CMMS packages today can manage assets across a multisite enterprise.
- Risk ranking, risk rating, risk score, and other risk-related terms
In my view, these are equivalent terms that encompass the probability and impact of failure. A risk score can be calculated for asset criticality, work order priority, incidents, and so on.
- Asset, equipment, rotating asset, component, part, serialized part
The main difference between assets and parts is that work order history is collected against a specific, serialized asset, equipment (a type of asset) or component (child asset), but not against a part. Also, parts are typically not serialized; they are kept in inventory and are managed through an inventory control system.
Why defining terms is important
A good leader has a vision, measureable goals and objectives, and a comprehensive action plan. Exceptional leaders can motivate people to accept that vision if and only if the definition of terms is clear. For example, if a leader proudly introduces an initiative dubbed the Lean Maintenance Project, some stakeholder groups may define the terms as follows:
- Lean: This means job cuts
- Maintenance: Management is once again picking on the maintenance department, when the real problems lie with operations, engineering, etc., and ultimately senior management
- Project: It’s yet another flavor-of-the-month initiative
Great leadership starts with a definition of terms that is well-understood at all levels in the organization. Without this, people act on their assumptions as to what is expected, which may not support what the leader intended. If you want to implement a comprehensive PM program that reduces risk, improves the lifecycle cost of assets, and gets more value out of your CMMS, start with a definition of terms aligned with these lofty objectives. Then set targets, provide an action plan, and monitor progress.