TABLE OF CONTENTS In the last chapter we looked at aspects of reliability engineering that can be of use to the maintenance practitioner. We discussed some of the underlying principles that can help us identify reliability parameters from historical maintenance records. In order to apply this knowledge, it is useful to understand the nature of failure. In this chapter, we will examine the following.
Failure in relation to the required performance standards; critical, degraded, and incipient failures;
Significance of the operating context;
Use of failures as a method of control of the process;
Role of maintenance in restoration of desired performance;
Incipiency and its use in condition-based maintenance;
Age-related failures;
System-level failures;
Human errors and the effect of stress, sleep cycles, and shift patterns;
Role of feelings and emotions and how these affect our reactions to situations.
Failure is the inability of an item of equipment, a sub-system, or system to meet a set of predetermined performance standards. This means that we have some expectations, which we can express quantitatively. For example, we can expect the discharge pressure of a centrifugal pump to be 10 bar gauge at 1000 liters per minute. In some cases, we can define our expectations within a band of acceptable performance. For example, the discharge flow of this pump should be 950-1000 liters per minute at 10 bar gauge. The performance standard may be for the system, sub-system, equipment, or component in question. These standards relate to what we...
