Introduction

Abstract

Failure is inevitable for everything in the real world, and engineering systems are no exception. The impact of failures varies from minor inconvenience and costs to personal injury, significant economic loss, and death. Examples of major accidents are those at the Three Mile Island and Chernobyl nuclear plants, the gas leak at the Bhopal pesticide plant, and the Challenger space shuttle explosion. Causes of failure include bad engineering design, faulty manufacturing, inadequate testing, human error, poor maintenance, improper use, and lack of protection against excessive stress. Designers, manufacturers, and end users strive to minimize the occurrence and recurrence of failures. In order to minimize failures in engineering systems, it is essential to understand why and how failures occur. It is also important to know how often such failures may occur. Reliability deals with the failure concept, whereas safety deals with the consequences after the failure. Inherent safety systems/measures ensure the consequences of failures are minimal. Reliability and safety engineering attempts to study, characterize, measure, and analyze the failure, repair, and consequences of failure of systems in order to improve their operational use by increasing their design life, eliminating or reducing the likelihood of failures and risky consequences, and reducing downtime, thereby increasing available operating time at the lowest possible life cycle costs.