Reliability, Maintainability and Risk, 8th Edition

Chapter 2. Understanding Terms and Jargon

2.1. Defining Failure and Failure Modes

Before introducing the various reliability parameters it is essential that the word failure is fully defined and understood. Unless the failed state of an item is defined, it is impossible to define a meaning for quality or reliability. There is only one definition of failure and that is:

Non-conformance to some defined performance criterion

Refinements that differentiate between terms such as defect, malfunction, failure, fault and reject are sometimes important in contract clauses, and in the classification and analysis of data, but should not be allowed to cloud the issue. These various terms merely include and exclude failures by type, cause, degree or use. For ...