Approaches to maintenance

The key approaches are considered in the context of time, deterioration of function and maintenance interventions.

Preventative and corrective maintenance

The basic principles are illustrated below.

An item deteriorates with time; its ability to meet its functional requirements decreases. At a critical level the item will fail to meet its functional requirements.

• Preventative maintenance is carried out before this critical time.
• Corrective maintenance is carried out after this critical time.

Figure 1: Corrective and preventative maintenance

Figure 2: Condition based maintenance

Figure 3: Planned maintenance