Deriving Functional Safety Requirements Using Undesired Combination State Templates

Functional Safety (FS) has become a major consideration during the development of embedded and reactive systems. When incorporating functional safety into a system under development, the engineer must be cognitive of not just system requirements, but safety requirements as well. These safety requirements are typically derived from an initial set of hazard and risk assessments. While there are various means of performing these assessments, there is a particular classification of hazards, based on undesired combination states that may be overlooked by other techniques. In this paper, we propose a technique that addresses these hazards, using Undesired Combination States Templates (UDCST). The technique has been conceived to accommodate the constraints on time and cost typically encountered in industry. We demonstrate the technique with two real world applications.