System Safety for the 21st Century, 2nd Edition

CHAPTER 2Fundamentals of System Safety

BASIC DEFINITIONS

One of the major problems confronting the system safety community is a lack of standardization or commonality. (This problem is discussed in detail in Chapter 4.) Presenting “universally accepted” definitions to even basic terms is therefore difficult because, by and large, they do not exist. The following terms are defined in nontechnical language to ensure the reader understands each term as used in this book. Specific definitions from documents widely used in the system safety effort are contained in the glossary, and definitions used by specific organizations are included in Chapter 3.

• Safety: Freedom from harm. Safety is achieved by doing things right the first time, every time.
• System: A composite of people, procedures, and plant and hardware working within a given environment to perform a given task (Fig. 2‐1).
• System safety: The discipline that uses systematic engineering and management techniques to aid in making systems safe throughout their life cycles.
• Hazard: Something that can cause significant harm.
• Risk: The chance of harm, in terms of severity and probability.
• Safety community: That group of individuals who provide staff support to the line organization in support of the safety effort. It includes occupational and industrial safety, system safety, industrial hygiene, health, occupational medicine, environmental safety, fire protection, reliability, maintainability, and quality assurance personnel.