Discrete manufacturing and process industries move towards flexible production to cope with individualization. Safety systems often counteract these developments. In this paper, a generalized methodology to draft an overall safety concept using different technologies is presented. Motivated by use-cases from both domains, requirements for future safety systems are described and summarized in a structured way. These requirements are then generalized and classified in building blocks to fulfill the needs of flexible functional safety. A methodology to structure safety systems and their general parts is presented. The used building blocks refer to aspects as interfaces, communication, and certification. Within the building blocks different technologies can be applied, to fulfill the part of the safety system accordingly.