Particular emphasis is placed on the importance of the product-based safety rationale within the argument and the role this rationale should play in assessing functional safety.
In this paper, we categorise and analyse the main argument structures required of a safety case and specify the relationships that exist between these structures. More importantly, the standard does not describe how the safety argument should be evaluated in the functional safety assessment process.
However, the standard does not provide practical guidelines for how it should be developed and reviewed. In order to justify freedom from unreasonable risk, a safety argument should be developed in which the safety requirements are shown to be complete and satisfied by the evidence generated from the ISO 26262 work products. (The blue iso-surface connects all locations having 90F and forms a closed surface. Compliance with the automotive standard ISO 26262 requires the development of a safety case for electrical and/or electronic (E/E) systems whose malfunction has the potential to lead to an unreasonable level of risk. Figure 8 Blue iso-surface showing 90F plume for Scenario 2, 20 minutes into cycle 1.