Mechanical Technology February 2015

Mechanical Technology — February 2015

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Proactive maintenance, lubrication and contamination management

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aintenance is perhaps not

the most glamorous field

of engineering, but it is a

fundamentally important

one. Depending on where you live and

work, the result of maintenance – or the

lack of it – is seen and felt by every one

of us. So it matters.

The subject of maintenance is a com-

plex one. In fact far more complex than

anyone not directly involved will give

credit for. Recognition of the complexity

and indeed, importance of maintenance

in asset management are found in the

PAS 55 standard and more recently

in the publication of ISO 55000. This

holds true for profit oriented businesses

and public service organisations alike. It

is also interwoven with related matters

including plant efficiency, overall-equip-

ment-effectiveness, cost-of-ownership,

lifecycle-cost, plant-life-extension, etc. Of

one thing there can be no doubt, getting

it wrong can make the difference between

a profitable business or admired public

service and a failing organisation.

A small indication of the complexity

can be seen in the wide variety of terms

commonly encountered for describing

various maintenance strategies: reactive,

preventative, condition-based, run-to-

failure, predictive, reliability-centred,

corrective, proactive, evidence-based,

and so on. And underestimating mainte-

nance can be very costly. Simply put, it

is relevant to everyone who owns or is re-

sponsible for a physical asset of any kind.

Are these terms simply marketing

hype, or are they linked to meaningful

and substantive variations in mainte-

nance strategy? Are they consequential?

If they are meaningful, what do they

mean? Many textbooks have been written

on these subjects over a long period of

time by very bright, knowledgeable and

experienced people. We will certainly

not fool ourselves into thinking that we

can properly do justice to them here.

However, there is merit in gaining a

basic understanding so as to see how

different maintenance strategies and

techniques can make a difference. With

ageing infrastructure all around, along

with economic realities that seldom

permit wholescale asset replacement, it

is becoming more and more important to

get maintenance right.

There was a time when an asset was

created or acquired in order to deliver a

function and, for all practical purposes,

its only role was to ensure continu-

ity in providing that function. Now, it

is usually equally, or sometimes even

more important, to consider safety and

the environment, that is, not only are

the maintenance processes important,

but also their impact. This, along with

the multi-disciplinary nature of today’s

plant and equipment, are the main

reasons why maintenance has become

so complex.

Since most of the terms used to

describe maintenance strategies mean

different things to different people, we

should begin by defining what we mean.

Here, we take the bigger picture view.

When reduced to the basics and using

common language meanings, there are

In this new regular maintenance column, Mario Kuisis of Martec (left), the reliability

enhancement specialist, introduces the essential approaches to maintenance and points

out that each of them has its place in extending life and maximising productivity. The

challenge for the responsible maintenance manager, he suggests, is to decide which

strategy to adopt for a particular asset in order to balance the benefits of asset reliability

with the cost of asset maintenance.

Martec specialises in reliability enhancement using modern technologies such as the SDT

ultrasound detectors for preventative maintenance.

Proactive maintenance – panacea

at least five possible approaches to main-

tenance. We will consider them below

in the order of their general evolution

in industry:

Passive maintenance

means do noth-

ing intentionally. Only think about

what to do when an asset fails. As-

sess the situation when it happens,

then act according to the prevailing

circumstances. Risk is completely

unmanaged.

Reactive maintenance

means plan-

ning for failure. Not to cause failure,

but pre-planning for the eventuality,

i.e. what will be done when it oc-

curs? No particular steps are taken

to prevent failure. The time and con-

sequential damages associated with

the failure are unknown. While the

consequences of a failure may be

mitigated to some extent, risk remains

substantially unmanaged.

Preventative maintenance

ostensibly

seeks to prevent failure, but is a mis-

nomer. Maintenance is routinely per-

formed on a time or operations basis

with the aim of preventing failures,

however failure remains inevitable.

Done well, mean time before failure

Mario on maintenance