Transdisciplinary Engineering Design Process

8Risk, Reliability, and Safety

Often the difference between a successful man and a failure is not one's better abilities or ideas, but the courage that one has to bet on his ideas, to take a calculated risk, and to act.

Maxwell Maltz

8.1 Introduction

This chapter introduces the concept of risk management, reliability, and safety as applied to engineering practice. Risk, reliability, and safety are three main components of a system design. There is a natural conflict between reliability and safety. High system reliability and performance are often achieved through the proper balance between performance and reliability so that an adequate safety factor is provided.

Customers expect to obtain reliable and maintainable systems that are of high quality, readily available and dependable, and able to satisfy their needs with some fair and reasonable cost parameters. A focus on maintainability in the design process results in a system that can be maintained realistically within given time constraints. Availability is also an important parameter in complex systems. Having high reliability does not ensure that the system will be operational (available) when needed. Conversely, a system can be available but not reliable. System dependability is an important design parameter that provides a measure of the system condition combining its reliability and maintainability. This chapter examines the mathematical relationships involved to determine the importance of the above-mentioned parameters ...