TABLE OF CONTENTS Definitions are given below of some of the more important terms used in this book. They are broadly in line with those given in the British Standards publication BS 3811:1984, but some have been significantly amended or extended by the author. The list does not include definitions already given clearly in the main text.
| Maintenance | The combination of all technical and associated administrative actions intended to retain an item in, or restore it to, a state in which it can perform its required function. |
| Preventive maintenance | The maintenance carried out at pre-determined intervals, or corresponding to prescribed criteria, and intended to reduce the probability of failure or the performance degradation of an item. Preventive maintenance is planned and scheduled (or carried out on opportunity). |
| Condition-based maintenance | The preventive maintenance initiated as a result of knowledge of the condition of an item derived from periodic, routine or continuous monitoring. |
| Condition monitoring | This periodic, routine, or continuous measurement and interpretation of data to indicate the condition of an item. |
| Corrective maintenance | The maintenance carried out after a failure has occurred and intended to restore an item to a state in which it can perform its required function. Corrective maintenance can be planned and scheduled. |
| Emergency maintenance | The corrective maintenance which it is necessary to put in hand immediately to avoid serious consequences. Thus, emergency maintenance cannot be scheduled. In some cases, however, it can be planned for by ensuring that decision guidelines have been prepared and that necessary resources will be available. |
