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 Excerpt from our

 RCM textbook.

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1.1 The Changing World of Maintenance

Over the past twenty years, maintenance has changed, perhaps more so than any other management discipline. The changes are due to a huge increase in the number and variety of physical assets (plant, equipment and buildings) which must be maintained throughout the world, much more complex designs, new maintenance techniques and changing views on maintenance organization and responsibilities.

Maintenance is also responding to changing expectations. These include a rapidly growing awareness of the extent to which equipment failure affects safety and the environment, a growing awareness of the connection between maintenance and product quality, and increasing pressure to achieve high plant availability and to contain costs.

The changes are testing attitudes and skills in all branches of industry to the limit. Maintenance people are having to adopt completely new ways of thinking and acting, as engineers and as managers. At the same time the limitations of maintenance systems are becoming increasingly apparent, no matter how much they are computerized.

In the face of this avalanche of change, managers everywhere are looking for a new approach to maintenance. They want to avoid the false starts and dead ends which always accompany major upheavals. Instead they seek a strategic framework which synthesizes the new developments into a coherent pattern, so that they can evaluate them sensibly and apply those likely to be of most value to them and their companies.

This book describes a philosophy which provides just such a frame-work. It is called Reliability-centered Maintenance, or RCM

If it is applied correctly, RCM transforms the relationships between the undertakings which use it, their existing physical assets and the people who operate and maintain those assets. It also enables new assets to be put into effective service with great speed, confidence and precision. 

This chapter provides a brief introduction to RCM, starting with a look at how maintenance has evolved over the past fifty years. 

1.2 Reliability-Centered Maintenance 

Since the 1930's, the evolution of maintenance can be traced through three generations. RCM is rapidly becoming a cornerstone of the Third Generation, but this generation can only be viewed in perspective in the light of the First and Second Generations.

The First Generation

The First Generation covers the period up to World War II. In those days industry was not very highly mechanized, so downtime did not matter much. This meant that the prevention of equipment failure was not a very high priority in the minds of most managers. At the same time, most equipment was simple and much of it was over-designed. This made it reliable and easy to repair. As a result, there was no need for systematic maintenance of any sort beyond simple cleaning, servicing and lubrication routines. The need for skills was also lower than it is today.

The Second Generation

Things changed dramatically during World War II. Wartime pressures increased the demand for goods of all kinds while the supply of industrial manpower dropped sharply. This led to increased mechanization. By the 1950's machines of all types were more numerous and more complex. Industry was beginning to depend on them.

As this dependence grew, downtime came into sharper focus. This led to the idea that equipment failures could and should be prevented, which led in turn to the concept of preventive maintenance. In the 1960's, this consisted mainly of equipment overhauls done at fixed intervals.

The cost of maintenance also started to rise sharply relative to other operating costs. This led to the growth of maintenance planning and control systems. These have helped greatly to bring maintenance under control, and are now an established part of the practice of maintenance.

Finally, the amount of capital tied up in fixed assets together with a sharp increase in the cost of that capital led people to start seeking ways in which they could maximize the life of the assets.

The Third Generation

Since the mid-seventies, the process of change in industry has gathered even greater momentum. The changes can be classified under the headings of new expectations, new research and new techniques.


     Figure 1. 1 shows how expectations of maintenance have evolved.

Downtime has always affected the productive capability of physical assets by reducing output, increasing operating costs and interfering with customer service. By the 1960's and 1970's, this was already a major concern in the mining, manufacturing and transport sectors. In manufacturing, the effects of downtime are being aggravated by the worldwide move towards just-in-time systems, where reduced stocks of work-in-progress mean that quite small breakdowns are now much more likely to stop a whole plant. In recent times, the growth of mechanization and automation has meant that reliability and availability have now also become key issues in sectors as diverse as health care, data processing, telecommunications and building management.

Greater automation also means that more and more failures affect our ability to sustain satisfactory quality standards. This applies as much to standards of service as it does to product quality. For instance, equipment failures can affect climate control in buildings and the punctuality of transport networks as much as they can interfere with the consistent achievement of specified tolerances in manufacturing.

More and more failures have serious safety or environmental consequences, at a time when standards in these areas are rising rapidly. In some parts of the world, the point is approaching where organizations either conform to society's safety and environmental expectations, or they cease to operate. This adds an order of magnitude to our dependence on the integrity of our physical assets - one which goes beyond cost and which becomes a simple matter of organizational survival.

At the same time as our dependence on physical assets is growing, so too is their cost - to operate and to own. To secure the maximum return on the investment which they represent, they must be kept working efficiently for as long as we want them to.

Finally, the cost of maintenance itself is still rising, in absolute terms and as a proportion of total expenditure. In some industries, it is now the second highest or even the highest element of operating costs. As a result, in only thirty years it has moved from almost nowhere to the top of the league as a cost control priority.

New research

Quite apart from greater expectations, new research is changing many of our most basic beliefs about age and failure. In particular, it is apparent that there is less and less connection between the operating age of most assets and how likely they are to fail. 

Figure 1.2 shows how the earliest view of failure was simply that as things got older, they were more likely to fail. A growing awareness of 'infant mortality' led to widespread Second Generation belief in the "bathtub" curve.


However, Third Generation research has revealed that not one or two but six failure patterns actually occur in practice. This is discussed in detail later, but it too is having a profound effect on maintenance. 

New techniques

There has been explosive growth in new maintenance concepts and techniques. Hundreds have been developed over the past fifteen years, and more are emerging every week.

Figure 1.3 shows how the classical emphasis on overhauls and administrative systems has grown to include many new developments in a number of different fields.


The new developments include:

  • decision support tools, such as hazard studies, failure modes and effects analyses and expert systems
  • new maintenance techniques, such as condition monitoring
  • designing equipment with a much greater emphasis on reliability and maintainability
  • a major shift in organizational thinking towards participation, team-working and flexibility. 

A major challenge facing maintenance people nowadays is not only to learn what these techniques are, but to decide which are worthwhile and which are not in their own organizations. If we make the right choices, it is possible to improve asset performance and at the same time contain and even reduce the cost of maintenance. If we make the wrong choices, new problems are created while existing problems only get worse.

The challenges facing maintenance

In a nutshell, the key challenges facing modem maintenance managers can be summarized as follows: 

- to select the most appropriate techniques to deal with each type of failure process in order to fulfill all the expectations of the owners of the assets, the users of the assets and of society as a whole
- in the most cost-effective and enduring fashion
- with the active support and co-operation of all the people involved.

RCM provides a framework which enables users to respond to these challenges, quickly and simply. It does so because it never loses sight of the fact that maintenance is about physical assets. If these assets did not exist, the maintenance function itself would not exist. So RCM starts with a comprehensive, zero-based review of the maintenance requirements of each, asset in its operating context. 

All too often, these requirements are taken for granted. This results in the development of organization structures, the deployment of resources and the implementation of systems on the basis of incomplete or incorrect assumptions about the real needs of the assets. On the other hand, if these requirements are defined correctly in the light of modem thinking, it is possible to achieve quite remarkable step changes in maintenance efficiency and effectiveness.

The rest of this chapter introduces RCM in more detail. It begins by exploring the meaning of 'maintenance' itself. It goes on to define RCM and to describe the seven key steps involved in applying this process.