Generating alternative modules for a plant alarm system based on first-out alarm alternative signals

Support is required for operator activity in the correcting abnormalities in chemical plants. A plant alarm system must provide useful information to operators as the third layer of the Independent Protection Layers. Therefore, a method for designing a plant alarm system is important for plant safety. Because plants are modified throughout their plant lifecycles, any alarm systems need to be properly managed throughout the plant lifecycles. To manage the changes, the design rationale of the alarm system should be explained explicitly. Takeda et al. (2013) [3] proposed a logical and systematic alarm system design method that explicitly explains design rationales from know-why information for appropriate management of change throughout the plant lifecycle. For the combined or branched component of a cause-effect (CE) model, multiple alternative modules have been proposed. We propose a method of generating alternative modules for a plant alarm system based on first-out alarm alternative signals for the combined or branched component of a CE model.