DEFINING SAFETY REQUIREMENTS

One of the biggest challenges, and a common problem for many safety engineers is understanding how to define and identify safety requirements. Most standards discuss safety requirements as though they are unique requirements independent of the design or performance requirements. Another common misconception is that all safety requirements are derived requirements.

Safety performance requirements are just as important to define as operational or functional performance requirements. In truth, there are rarely ever any pure safety requirements. There are performance and design requirements that have safety influence or the potential for hazardous effect. Defining the safety requirements should be consistent with, and fully integrated with, the systems engineering requirements development effort.

Many references are made with regard to addressing safety requirements. Oddly though there is very little to define what a safety requirement is. In order to establish any safety process, the criteria for a defining and determining safety requirements must be defined. SSSE has had significant success with the following approach to defining safety requirements.

There are two primary parts to defining safety requirements:

1. The Safety Basis of Certification
2. Error detection and deterministic failure response

Contact SSSE to learn how to define and implement the safety basis of certification and integrate error detection and deterministic failure behaviors into system safety and software safety processes.