Juraj Grencik

University of Zilina

juraj.grencik@fstroj.uniza.sk

Slovakia

Proactive Maintenance is a generally known concept, although this term is not mentioned in the EN 13 306 Maintenance Terminology standard [1]. The inventors of Reliability Centred Maintenance (RCM), Thomas D. Matteson and Anthony Smith [2] recognized that insufficient proactive maintenance problems were due to the fact that the majority of maintenance personnel were acting in a “reactive manner”. This resulted in increased costs caused by a combination of return of the equipment into operation and penalties for lost production.

Similarly, John Moubray stresses in his bestseller RCM [3] that proactive maintenance is an important part of RCM. As a “domestic” example, I want to mention a system developed by CMMS s.r.o. called “Proactinance” [4] focusing on the basic problems of the proper lubrication and alignment of rotating machines. Also my colleague, Professor Hana Pacaiova from the Technical University of Kosice always promotes the proactive maintenance strategy as the most efficient approach in preventing failures before they occur [5]. The proactive approach in maintenance seems to be a generally accepted concept. The European terminology standard however, does not use the term of “Proactive Maintenance”. The term “preventive” has a much broader meaning in Europe than on the American continent; in the Americas the term “preventive maintenance” is usually understood as what in Europe is called “predetermined maintenance” (EN 13 306): maintenance carried out in accordance with established intervals of time or number of units of use, but without previous condition investigation. A more advanced area of preventive maintenance in the European context is “condition based maintenance” including a combination of condition monitoring and/or inspection and/or testing, analysis and the ensuing maintenance actions. At the top of this is “predictive maintenance”, condition based maintenance, which is carried out based on forecasts derived from repeated analysis or known characteristics and evaluation of the significant parameters of the degradation of the item [1].

In the American perception there is “preventive maintenance” (PM) and “predictive maintenance” (PdM), and at the top is “proactive maintenance” (PaM), the central theme of which involves directing corrective actions focusing on failure root causes, not the active failure symptoms, faults or machine wear conditions. It keeps operating conditions within the limits where a machine and its components will not fail. The machine conditions are monitored and actions are determined to return the machine into a safe state. Maintenance actions are taken before and not after the failure. In Europe, understanding preventive maintenance certainly covers also principles of the proactive maintenance.

Figure 1. The surface of Mars, The Moon and Slovak roads (source Internet).

Perhaps the main feature distinguishing proactive from predictive maintenance, is its focus on discovering the root causes of failures. For example, bearings can be replaced before failure, based on condition monitoring when unacceptable vibrations occur. But if the vibration was caused by misalignment, this state will be frequently repeated. Once the machines are aligned, increased vibrations will take a much longer time to occur as the operational conditions of the machine have been improved. Another example of this can be lubrication; an increased amount of abrasive particles in oils may speed up the wear of gears. The gears may be replaced frequently before they actually fail, but improved oil filtration can help to reduce the wear of gears. Again, the improved operational conditions result in the extended life of machine components.

We can also look at the definition of durability of an item, “the ability to perform a required function under given conditions of use and maintenance until a limiting state is reached”. The limiting state may be redefined by changes in conditions of use. The condition of use, or operational mode, is also an important factor for useful life. It is obvious that machines and technical equipment in general, as well as buildings and structures, are designed for specified and expected loading during their useful life.

One more well-known example from a different area is roads; shortening of the useful life (damage) of road pavement caused by the overloading of trucks and trailers on roads. Roads are designed and built for specified maximum admissible axle loads. When excessive axle load is repeatedly exerted, the consequence is that the useful life of road surface is dramatically shortened. And when unfavourable conditions from winter weather is added to this equation, the result is similar to the surface of Mars or The Moon (figure 1).

Proactive Operation

The conclusion is that a proactive approach to create optimum operating conditions for the machine is not only a matter of maintenance, but the machine operation plays an important role too. So, combining both terms gives “proactive operation”.

My thought was that this was a great invention – before I checked the concept on the Internet. As the Bible says: “nihil novi sub sole” (there is nothing new under the sun), or nowadays “everything is on the Internet”. One can find proactive operation for example in the work of Northamptonshire police, who uses this approach in proactive targeting offences caused by car and motorbike drivers that have been identified as a priority by the community.

There are reasons to emphasize the importance and close relation between operations and maintenance, especially when thinking and acting proactively. With regards to this relation, I recall the historical name of the “Operation and Maintenance of Rail Vehicles” department at the former University of Transport and Communications in Zilina. The founder of the department, professor Louda, was an open-minded person with a sound professional background in practice (maintenance of railway vehicles). He realized already 50 years ago that for the best utilization (exploitation) of rolling stock, both operation and maintenance are necessary.

Note – it is interesting, that the Polish maintenance society is actually the Polish exploitation society, as the Polish language does not have a word having the exact meaning of maintenance, but they use “eksploatacja” (utilization, exploitation). So they already combine operation and maintenance as a unified system.

Below are some areas, where proactive operation has the potential to extend useful life, save energy and operational costs of machines and facilities:

• Keeping a specified operational load (without overloading, misalignment, etc.)
• Keeping a specified (maximum and minimum) temperature
• Keeping specified output of a machine
• Cleaning of machines
• Proper filtration of liquids (oil, fuel, coolants, etc.)
• Qualified and cautious operators.

Summary

I agree that the above-mentioned principles belong to normal quality operations and the maintenance of machines and facilities. But that is what it is all about; proactive actions, either in maintenance or operations, are nothing more or less than to understand how the technology and facilities work and what they require in order to run at a smooth and high utilization rate.

»»References ››1. EN 13 306: 2010: Maintenance – Terminology ››2. Smith, A.M.: Reliability-centered maintenance. New York : McGraw-Hill, 1993 ››3. Moubray, J.: Reliability-centered Maintenance. Industrial Press Inc. New York 1997, ISBN 0-8311-3078-4 ››4. Valent, O.: Proactinance – the proactive maintenance solution. conference proceedings National Forum on Maintenance 2008, SSU, 2006, Vysoke Tatry, pp.94-98, ISBN 80-8070-541-0 ››5. P acaiova, H., Maintenance strategy as a basic tool for major hazard prevention. Conference proceedings from Euromaintenance 2008, 8-10 April 2008, Brussels ››6. https://www.northamptonshirealert. co.uk/da/19242/Police_departments_join_ forces_for_proactive_operation_.html