RCM has been successfully applied to ground industries
for over two decades
RCM2 is a logical discipline for the
development of efficient scheduled
(proactive) maintenance programs for
complex assets, and the on-going management
of such programs. These programs are called
reliability-centered maintenance (RCM2)
programs because they are centered on
achieving the inherent safety and
capabilities of assets at a minimum cost.
RCM2 is used to define maintenance
strategy. A central problem addressed with
RCM2 is how to determine which maintenance
tasks, if any, should be applied to an item
and how frequently assigned tasks should be
accomplished. The net result is a structured
blend of experience, judgment, and
to identify the right work at the right
Today more than ever there is a burning need
to increase asset performance while reducing
costs. This is not a new concept as a
typical asset undergoes between 30 and 50
reliability, maintenance and production
optimization initiatives per year.
A key to ensuring success is to shift from
the conventional repair and modification
approaches to a focus on failure consequence
mitigation – the core principle of RCM2.
the past 20
years, we have applied RCM to over 2000 sites
in 80 countries in every major ground industry over the
Read Chapter 1 of our RCM book
Humanity depends more and more on the wealth generated by the continued operation of highly mechanized and automated businesses and services. More than ever, these depend in turn on maintaining continued integrity of physical assets.
Economic demand for greater mechanization and automation means that reliability and availability are increasingly important to the bottom line. This also means that more and more type of failures increasingly affect our ability to sustain any quality standards. More and more failures have serious safety or environmental consequences, yet society's demands of better standards in these areas created situations where survival of the corporation or industry is dependent of the integrity of our physical assets. Also, at the same time as our dependence physical assets is growing, so is their cost - to operate and to own. To secure the maximum return on investment, they must be kept working efficiently as long we want them too. To achieve this, the cost of maintenance has been increasing in absolute terms, and in many industries is now the highest operation cost, so there is pressure to reduce spending on maintenance. How do we nationally balance all these conflicting demands?
We are more and more dependent on the wealth generated by the continued operation of highly mechanised and automated processes. We are also becoming increasingly dependent upon services taken for granted, such as the uninterrupted supply of electricity, trains which run on time, clean water and efficient waste treatment. It is amazing how much these in turn have come to depend on the continued integrity of physical assets. Assets which when they fail not only erode our wealth and upset and inconvenience us, but sometimes threaten our very survival. Equipment failures that lead to serious accidents not only affect the equipment operators, but are the leading cause of major environmental incidents - incidents which have become bywords such as Amoco Cadiz, Chernobyl, Bhopal and the Piper Alpha oil platform in the North Sea.
More and more corporation are beginning to recognise the extent to which society as a whole can be affected these incidents in addition to their potentially catastrophic financial implications. Not only did Piper Alpha kill 167 people, but insurance payments amounted to HK$1.2 billion and one quarter of North Sea oil production was shut down for several months - all because one crucial piece of equipment was not functional at one critical moment. As a result, businessmen everywhere are starting to place an increasingly high priority on learning more about what must really be done to manage equipment failures. This is especially true in Hong Kong following the tragedies and potential disasters which have occurred in recent months.
Now in all major corporations, maintenance is more than keeping equipment running, it is 'managing equipment failures'. What is more, most people believe that the more often and the more thoroughly something is maintained the safer it will be. In recent years, this has led to the development of preventive maintenance programmes which place great emphasis on comprehensive equipment overhauls at regular intervals.
However, following intensive research into the real causes of failure, the international civil aviation industry established some years ago that a surprisingly high proportion of the failures experienced by aircraft occurred wither soon after they were put into service or soon after a major overhaul. Similar finding in other industries have shown that regular overhauls very often - but not always - do more harm than good.
However, it is equally true to say that if equipment does not receive the right maintenance at the right time, it can also become unreliable and sometimes very dangerous.
This apparent contradiction led to a thirty-year search, beginning in the early 60’s, for a way to establish exactly what is meant by the term “maintenance”.
In the early stages of this search, it seemed that there were more questions than answers. Firstly, it began that there are several different methods of managing failure, each of which is appropriate in different circumstances. This led to a further search for a simple way of deciding when to use which method. When a universal decision framework had been developed - this alone took twenty-five years - it then became necessary to decide who was in the best position to make the decisions.
Once all of these questions had been answered, a process began to emerge which enabled people who use it to transform the effectiveness of the maintenance function in a remarkably short space of time. This process is known as “Reliability-centred Maintenance”, or RCM. To understand RCM in more details, it is worth looking more closely at how it was developed.
was the discovery that there a large number of
legitimate ways of managing failures.
These can be divided into five broad
The first category includes well-known
routine overhauls, where equipment is taken
to pieces and reassembled at fixed
intervals, and cases where components are
replaced at fixed intervals without checking
their condition. This
category is generally known as
preventive maintenance, and is
occasionally still appropriate, but far less
often than first thought.
The second category covers vast array of
techniques known as
predictive or condition-based maintenance.
This entails checking equipment regularly to
find out if it is in the process of failing,
and taking corrective action only if it is
do this when we check the oil level in our
cars - if the oil level is OK we take no
action, but if the level is low we add oil. In
industry, if sufficient warning that a
failure is about to occur can be obtained,
then this method provides engineers with
time to collect the necessary spares and
plan remedial action in a way which
The third category covers a special but
increasingly common class of equipment. These
are protective devices which usually can
fail in such a way that no-one knows that
they have failed unless someone makes a
special point of checking.
These checks differ from predictive
maintenance because they entail checking
whether an item
has failed, rather than checking whether
An apparently subtle difference
but one which profoundly affects both the
nature of the check and the frequency with
which it has to be done.
These checks are known as
detective maintenance. Typical
examples includes periodic checks on smoke
detectors and burglar alarms to find out if
they have failed.
The fourth broad category of failure
management techniques is known as
As the name suggests, this entails fixing
items either when it is immediately evident
that they have failed of their own accord
(normally referred to as a 'breakdown'), or
when they are found to be failing following
a predictive maintenance check, or if they
are found to be failed after a detective
The fifth and final way of dealing with
failures is to
change of design of the asset in such a
way that the failure no longer occurs, or if
it does occur, to change the consequences of
the failure in such a way that the failure
no longer matters.
Redesign usually is the last resort.
This is because the engineer on duty today
has to maintain the equipment as it exists
today, and not what should be there or what
might be there at some time in the future.
Since redesigns take time, we only challenge
the design when a cost-effective maintenance
programmes cannot be found.
Once the early researchers had gained a clear
understanding of the strengths and weaknesses
of these different approaches, the next step
was to develop a sensible basis of deciding
when to use which one. The
first point which became clear was that it is
too simplistic - and too dangerous - to
haphazardly choose any one of these
approaches are needed for different machines,
or even for different parts of the same
again about a private car.
We check the brakes and tyres for wear on a
regular basis - both forms of
preventive maintenance, while checking
periodically to see the hazard warning
On the other hand, changing the oil and the
spark plugs at fixed intervals is still
Then again, we would probably do not
routine maintenance at all on (say) the
cigarette lighter or the electric window
winders , and only arrange for them to be
repaired if they fail.
In trying to establish a sensible frame work
for making these choices, the aviation
industry realised that the reason why we worry
about failures at all is because they have
Sometimes failures only cost the fund of
the repair job.
More often, they interfere with production or
operations, in which case they usually cost
rather more than the direct cost of repair.
In the most serious cases, they can lead to
serious environmental incidents or kill people
Clearly, the more serious the consequences of
a failure, the more time and effort should be
spent on trying to prevent it.
This led the airlines to use a formal
evaluation of failure consequences as a basis
for deciding what maintenance should be done. The
decision-making framework which they developed
to do this is at the heart of Reliability-centred
The application of RCM starts with an analysis
of the functions of the equipment. This
is done in close consultation with the
Maintenance is all about preserving the
function of physical assets, so a
comprehensive review of equipment functions
enables everyone to agree on what maintenance
is trying to 'maintain’.
It is also surprising - sometimes very
surprising - how much people learn about how
the equipment is supposed to work.
Once the functions of the equipment have been
agreed, the next step is to analyse all the
ways in which it is reasonable likely to fail,
and what would happen if each failure actually
This step is called failure modes and effects
analysis, and it enables everyone to agree on
what they are actually trying to prevent when
they do 'preventive’ maintenance.
is to assess the consequences of each failure in a strict sequence. Depending on both the nature and the severity of the consequences, the final step is to select the most appropriate of the five types of maintenance listed above for dealing with the failure.
This process leads to much more tightly focused and far more effective maintenance programmes. RCM has contributed to a massive decrease in the number of civil aircraft accidents over the past thirty years - from more than sixty crashes per million takeoffs in 1960 to less than two per million takeoffs in 1988. Such results led to its widespread adoption in ground-based industries around the world. RCM has and is being used to initiate step changes in maintenance effectiveness - often in the space of a few months - by someone the world's leading companies in fields such as petrochemicals, food manufacture, pharmaceuticals, railways, electricity generation and distribution, mass housing, steel making, water distribution, military undertakings and auto-mobile manufacture.
Given the power of the RCM process and the speed with which it can produce results, the final questions concern how and by whom it should be applied. Most people tend to believe that the equipment supplier is in the best position to provide a viable maintenance programme for his equipment. However, no supplier - indeed no outsider - can possibly appreciated all the unique features of the user's business which will affect the machine throughout its life, nor can they fully appreciate all the ways in which the failure of their equipment might affect the users business. This means that although the supplier can - and in the case of new equipment, should play a part in developing such a programme, there is no way that he can do it all.
In practice, the organisations which have derived the most value from the RCM process are those which have developed the capability to apply it themselves. They do so using multi-disciplinary teams of people trained to use RCM under the guidance of even more highly trained individuals known as RCM facilitators. These teams usually include members of the operations department, because they understand most clearly what the equipment is to be used for and what the consequences are if it fails. The equipment users are the 'customers’ of the maintenance department, and it is wholly in keeping with all the principles of Total Quality that the customers should be involved in specifying the kind service they expect. The teams also include members of the maintenance function, because they tend to have the clearest understanding of what fails and what can be done to prevent or repair it.
Getting members of operations and maintenance departments to apply RCM together in this way not only ensures that the 'best' maintenance programme is drawn up with all the available information. It also causes two notoriously hostile sections of the business to start working together as a team to fulfill common, clearly understood objectives. This feature of RCM alone is causing it to be widely adopted by some of the world's largest multinational manufacturing organisations.
RCM is transforming the world of industrial maintenance from what is often seen as an expensive and erratic drain on resources, into truly proactive contributor to world-class manufacturing excellence.