Preventive maintenance

Preventive maintenance (PM) has the following meanings:

The primary goal of maintenance is to avoid or mitigate the consequences of failure of equipment. This may be by preventing the failure before it actually occurs which Planned Maintenance and Condition Based Maintenance help to achieve. It is designed to preserve and restore equipment reliability by replacing worn components before they actually fail. Preventive maintenance activities include partial or complete overhauls at specified periods, oil changes, lubrication, minor adjustments, and so on. In addition, workers can record equipment deterioration so they know to replace or repair worn parts before they cause system failure. The ideal preventive maintenance program would prevent any unnecessary and costly repairs.

Preventive maintenance for various equipment and facilities is quite nuanced. For instance, maintaining certain equipment may include a "preventive maintenance checklist" which includes small checks which can significantly extend service life. Furthermore, other considerations such as weather and equipment are taken into account; for instance, in the case of HVAC systems, maintenance is often performed before the hottest time of the year.

There is a controversy of sorts regarding the propriety of the usage "preventative".

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