ISA TR18.2.1-2018 was written in support of the standard ANSI/ISA-18.2-2016, Management of Alarm Systems for the Process Industries (March 2016), hereinafter referred to as ISA-18.2. The goal of this technical report is to provide guidance on how to implement the recommendations and the requirements described in the Alarm Philosophy clause (Clause 6) of the standard. It outlines potential approaches and provides specific examples that can be included in an alarm philosophy in order to properly manage the identification, rationalization, detailed design, implementation, operations, maintenance, monitoring and assessment, management of change, and audit life cycle work processes. Similar to ISA-18.2, this document is intended for those individuals and organizations that: manufacture or implement embedded alarm systems; manufacture or implement third-party alarm system software; design or install alarm systems; operate and/or maintain alarm systems; audit or assess alarm system performance.