TABLE OF CONTENTS Safety/Reliability engineering has not developed as a unified discipline, but has grown out of the integration of a number of activities which were previously the province of the engineer.
Since no human activity can enjoy zero risk, and no equipment a zero rate of failure, there has grown a safety technology for optimizing risk. This attempts to balance the risk against the benefits of the activities and the costs of further risk reduction.
Similarly, reliability engineering, beginning in the design phase, seeks to select the design compromise which balances the cost of failure reduction against the value of the enhancement.
The abbreviation RAMS is frequently used for ease of reference to reliability, availability, maintainability and safety-integrity.
Throughout the history of engineering, reliability improvement (also called reliability growth) arising as a natural consequence of the analysis of failure has long been a central feature of development. This test and correct principle had been practised long before the development of formal procedures for data collection and analysis because failure is usually self-evident and thus leads inevitably to design modifications.
The design of safety-related systems (for example, railway signalling) has evolved partly in response to the emergence of new technologies but largely as a result of lessons learnt from failures. The application of technology to hazardous areas requires the formal application of...
