Preventive Maintenance Approach
practice of Maintaining Infrastructure assets has evolved and improved markedly
in the last couple of decades. This development in the Infrastructure Industry
is due to a variety of factors, such as a big rise in the number and heterogeneity
of infrastructure assets that need to be maintained, complexity in their
designs & structure, new and upcoming maintenance tools & methods, heightened
safety standards and the ever changing global outlook on maintenance strategies.
the past decades, preventive maintenance was the most widely used maintenance
technique. It was deemed to be the most effective technique at disposal to the
construction & infrastructure industry. This preventive Maintenance
strategy was established on the assumption of a “cause-n-effect correlation” between the functional
reliability of the component and its scheduled maintenance. In turn, this
assumption was founded on the hypothesis that, since the mechanical components
of any system are subjected to regular “wear and tear”, their
reliability is directly associated to their operational lifetime. Hence it was
conjectured that the more routinely an equipment was serviced or overhauled,
the more secure it was against the possibility of any failure.
this strategy of preventive maintenance comes with a lot of limitations :
of system downtime:
Shutting down of a system, results in loss of productive time and consequently
a loss of revenue.
of system maintenance:
Utilization of resources to routinely perform inessential scheduled maintenance
of grave safety or environmental ramifications: Shutting down and starting-up a
facility is one of the high-risk operations, thus intrusive preventive
maintenance practice tends to increase the risk of environmental damage.
of systems: The
more complex the systems are, the more strenuous it is to perform planned/
Reliability Centered Maintenance
intent of an any efficient maintenance strategy is to avert or assuage the
consequences of failure, not to avert the failure itself. In other words: if
the ramifications of any failure do not have deleterious consequences on
safety, operations, environment or cost, then there is no exigency to proceed
with the scheduled maintenance.
to Nowlan and Heap, 1978, “A reliability-centered maintenance program
includes only those tasks which satisfy the criteria for both applicability and
effectiveness. The applicability of a task is determined by the characteristics
of the item, and its effectiveness is defined in terms of the consequences the
task is designed to prevent.”
strategy provides a framework for exploring the various functions and likely
failures for any asset, with an emphasis on safeguarding the system’s
functions, rather than equipment itself.