Maintenance Strategy

Picture below describe how much maintenance cost compare to maintenance strategy. Break down maintenance is highest cost and condition based is the lowest cost.

Breakdown Maintenance meaning repair when fails.

Predictive / Regular Preventive Maintenance meaning comprehensive maintenance in advance to reduce chance a trouble.

Condition Based Maintenance meaning maintenance as it needed just before problem arise.


Break Down Maintenance.
Advantages, can be the cheapest solution if the repair is easy and there is no safety risk or possibility of consequential damage.

Disadvantages, the cost of consequential damage can be high and there might be safety risk. The plant may be of a type which can not be allowed to stop suddenly because of product solidification or deterioration, etc. The failure may occur at an inconvenient time or, if the plant is mobile at an inconvenient place. the necessary staff and replacement components may not then be available.



Predictive / Preventive Maintenance.
Advantages, reduce the risk of failure in service. Enables the work and availability of special tools and spare parts to be planned well in advance. Is particularly appropriate for component which need changing because a capacity absorption such as filter element.

Disadvantages, Some failures will continue to occur in service because components do not fail at regularly intervals. The failure can be unexpected and inconvenient. During the overhaul many components in good condition will be stripped and inspected unnecessarily. Mistakes can be made on reassembly so that the plant can end up in a worse condition after the overhaul. The overhaul process can take a considerable time resulting in a major loss of profitable production.



Conditioned-based Maintenance.
Advantages, enables the plant to be left in service until a failure is about to occur. It can then be withdrawn from service in a panned manner and repaired at minimum cost. Consequential damage from a failure can be avoided.

Disadvantages, can only detect failure which show a progression to failure, which enables the incipient failure to be detected. Components with a sudden failure mode can not provide the required advanced detection. Failures of components due to an unexpected random overload in service can not be avoided, even by this method.



Others.
Opportunistic maintenance carried out when the plant or equipment happens to become available.
Advantages, the maintenance can be carried out with no loss of effective operating time.
Disadvantages, staff and spare parts have to be kept available which may cause increase costs. is only practical in combination with condition based maintenance or some preventive maintenance, because otherwise any work which needs to be done is not known about. Breakdowns are still likely to occur in service.

Maintenance / replacement based on expected component life.
Advantages, is the only safe method usable for components which have a sudden failure mode.
Disadvantages, requires monitoring of the operating conditions of the components so that its expected life can be estimated. If all failures are to be avoided many components will need to be changed when individually they have a useful life still remaining.