IEC 880: feedback of experience and guidelines for future work

This paper presents an outline of the work currently done at Electricite de France for the identification of requirements applicable to software in category, B (as defined by publication 1226 of the IEC) systems. The first part presents an analysis of the weaknesses of publication 880 of the IEC, an existing and related standard expressing requirements applicable to software in category A systems. Based on this feedback of experience, the second part identifies some general recommendations and guidelines that should be followed for the establishment of requirements in a standard for software. The third part presents the main technical objectives that can be proposed for software in category B systems. These technical objectives are all derived from a unique primacy objective: safety integrity, i.e., the likelihood of software to achieve its safety functions under all stated conditions within a stated period of time