Integrated hazards method (IHM): a new safety allocation technique

The acronym R.A.M.S. (Reliability, Availability, Maintainability, Safety) concerns the application of important methodologies for designing and managing complex systems. The present work proposes some guide lines for a right analysis and consequently allocation of the Safety parameter during the design and management phases of a complex system. The identification and allocation of Safety requirements is the process that assigns these requirements to each part and subsystem, allowing the whole system to reach the Safety target predesigned. The starting point is the analysis of the allocation techniques present in literature. Starting from the application fields, advantages and disadvantages of the above techniques, the work proposes a new methodology, called "Integrated Hazards Method" (IHM), first of all applicable to the pre-design phase of complex systems, but also to following phases of development and management, systematically and economically. The mathematical formulation of the new method has been developed thanks to a case study, an unmanned aerospace system. We have validated the obtained results through an Analysis of Sensitivity, showing a great flexibility of the new mathematical formulation, able to discriminate among the parts of the system, in order to guarantee high values of Safety.