Scheduled overhauls or replacement, on condition and failure finding tasks
(themselves time-based), are all part of the preventive maintenance program.
When work is carried out on a predictive or expected basis, it is called proactive
maintenance. If work is carried out after the equipment has functionally failed, it is
called reactive maintenance. When the incipiency period is very small, not enough
time is available for planning the work. There are reduced prospects to minimize
production losses, which might be unavoidable. In such cases, the timing of the work
is outside control, and the corrective maintenance is called reactive. Thus, corrective
maintenance work can be either proactive or reactive, depending on the operating
conditions.
All preventive maintenance can be planned and scheduled, i.e., prepared well
ahead of intended implementation.
Although, in most cases, corrective maintenance can be planned as well, however, less time is available to program the work, since the beginning of failure has
already arisen. The term scheduling means the distribution of materials and
resources as well as fixing a start and finish date to the job required.
It is difficult to plan breakdown maintenance, as the exact scope and timing are
unknown in advance, which therefore is less efficient as regards resource use and
time required. Thus, it is fashionable not to think highly of breakdown maintenance,
in contrast to preventive and predictive maintenance, because the former results in
unwanted maintenance expenditure and equipment downtime.
From a broader perspective, however, there are many failure modes entailing
insignificant effects on the infrastructure service as a whole. Therefore, in such cases,
it is cost-effective to accept the failures occurring before considering any action.
Preventive maintenance entails that equipment components become “due” for
maintenance, even though they are performing perfectly well. Each strategy is
appropriate under certain circumstances, and the choice must be based on the most
appropriate method to reduce risks. When the consequences are considered negligible, the risk is usually low, so a breakdown strategy might be appropriate. If there is a
hazard to safety, production, or the environment, preventive strategies are appropriate. Question: A car servicing regularly carried out (every 10,000 km, or as prescribed) tries to minimize the risk of the car breaking down, without warning, on the
road. In most cases, the consequence is probably negligible, as having to walk to
fetch a mechanic, etc. However, somebody whose car breaks down on a busy road,
when he is in a hurry, will think many times about not going for his regular
servicing!
20.3.3 The Need for Maintenance
Narayan (1998) asserts that maintenance is required to diminish the quantified risk of
serious safety, environmental, adverse publicity to a minimum or minimize production incidents that can reduce the sustainability and lucrativeness of the organisation,
both in the short and long term, and to carry this out at the lowest total cost.
580
20 Human Resources Management for Infrastructure
(themselves time-based), are all part of the preventive maintenance program.
When work is carried out on a predictive or expected basis, it is called proactive
maintenance. If work is carried out after the equipment has functionally failed, it is
called reactive maintenance. When the incipiency period is very small, not enough
time is available for planning the work. There are reduced prospects to minimize
production losses, which might be unavoidable. In such cases, the timing of the work
is outside control, and the corrective maintenance is called reactive. Thus, corrective
maintenance work can be either proactive or reactive, depending on the operating
conditions.
All preventive maintenance can be planned and scheduled, i.e., prepared well
ahead of intended implementation.
Although, in most cases, corrective maintenance can be planned as well, however, less time is available to program the work, since the beginning of failure has
already arisen. The term scheduling means the distribution of materials and
resources as well as fixing a start and finish date to the job required.
It is difficult to plan breakdown maintenance, as the exact scope and timing are
unknown in advance, which therefore is less efficient as regards resource use and
time required. Thus, it is fashionable not to think highly of breakdown maintenance,
in contrast to preventive and predictive maintenance, because the former results in
unwanted maintenance expenditure and equipment downtime.
From a broader perspective, however, there are many failure modes entailing
insignificant effects on the infrastructure service as a whole. Therefore, in such cases,
it is cost-effective to accept the failures occurring before considering any action.
Preventive maintenance entails that equipment components become “due” for
maintenance, even though they are performing perfectly well. Each strategy is
appropriate under certain circumstances, and the choice must be based on the most
appropriate method to reduce risks. When the consequences are considered negligible, the risk is usually low, so a breakdown strategy might be appropriate. If there is a
hazard to safety, production, or the environment, preventive strategies are appropriate. Question: A car servicing regularly carried out (every 10,000 km, or as prescribed) tries to minimize the risk of the car breaking down, without warning, on the
road. In most cases, the consequence is probably negligible, as having to walk to
fetch a mechanic, etc. However, somebody whose car breaks down on a busy road,
when he is in a hurry, will think many times about not going for his regular
servicing!
20.3.3 The Need for Maintenance
Narayan (1998) asserts that maintenance is required to diminish the quantified risk of
serious safety, environmental, adverse publicity to a minimum or minimize production incidents that can reduce the sustainability and lucrativeness of the organisation,
both in the short and long term, and to carry this out at the lowest total cost.
580
20 Human Resources Management for Infrastructure