Maintenance Policies

The following table describes various maintenance techniques that are used. Which policy are you using? When and where?

Breakdown maintenance Maintenance carried out on equipment after breakdown of the machine or equipment has actually occurred.
Planned Preventative Maintenance (PM) Carried out on a planned basis and depends on a 'schedule of work' being carried out at a predetermined time. It maximizes the maintenance team utilization and effectiveness and also reduces the running and spare parts costs.
Fixed Base Maintenance This consists of the replacement of components at a fixed period so that they can be replaced before they fail as a result of normal wear and tear.
Condition Based Monitoring (CBM)

Maintenance work which is carried out on an item when its condition calls for attention. This method of maintenance can also be of a preventative nature. This calls for tests and checks to be conducted on the fleet or equipment using particle count, spectrographic and vibration analysis, etc. By these methods:

  1. Faults can be detected before failure.
  2. Faults can be diagnosed before failure.
  3. An estimate of the time to failure may be calculated.

This method is normally applied to expensive or complex equipment.

Operated to Failure This policy allows the item to fail in service. In many cases, the item may not justify routine maintenance due to the value of the item and the cost to replace it. Care must be taken to ensure that if the item is allowed to fail in service, its failure does not result in secondary damage to the equipment.
Opportunity Maintenance For complex items and continuously operating plant or machinery, maintenance is carried out when the plant has been stopped for any reason. This type of maintenance calls for careful planning and preparation, since all the manpower, equipment, schedule and spares must be put onto the task at short notice. 
Design Out Policy This policy is concerned with the result of data analysis of the maintenance information. This usually identifies areas of high defect rate and high cost. These causes may be as a result of poor design or the equipment failing to meet the specification for a number of reasons, ie, poor quality of material, operating outside of limits or the effects of environmental conditions. This usually calls for modification and/or redesign work to be carried out to reduce the maintenance penalty.