Software Engineering Institute

As software-intensive systems become more pervasive, more and more safety-critical systems are being developed and deployed. Yet when most people think about safety requirements, they think of safety-critical functional requirements, which are requirements that have critical safety ramifications if not correctly implemented. However, there are actually four major classifications of safety-related requirements: (1) pure safety requirements, (2) safety-significant requirements, (3) safety constraints, and (4) requirements for safety systems. This paper describes a taxonomy of these different kinds of safety-related requirements, and clearly and briefly defines and describes each of them.