This recommended practice is provided for the benefit of design engineers and, ultimately, plant operators. Use of this recommended practice will result in a more coherent and useful application of plant alarms for operations personnel. The goal of this recommended practice is to reduce alarm discrepancies, clutter, excessive noise levels, and information overload, but it is not intended for post-factum analysis of events. This recommended practice will address the following alarm-related issues. Functional grouping Prioritization Order and consistency Colors Formats and displays Audio tone and pitch Acknowledge, reset, and test functions Nuisance alarms These items are addressed both individually and with respect to their relationships with one another. This recommended practice pertains to alarms displayed using lights or light boxes, but not software-based alarms (e.g., CRP-based alarms) and is intended to supplement the information provided by ISA-18.1-1979 (R2004), Annunciator Sequences and Specifications.