General applicability

This technical report addresses alarm systems for facilities in the process industries to improve safety, quality, and productivity.

In the design stage, the alarm attributes are specified and designed based on the requirements found in the alarm philosophy and determined by rationalization (e.g., alarm priority and setpoint). There are three areas of design: basic alarm design, HMI design, and design of advanced alarming techniques. This technical report addresses considerations for the basic alarm design. Note that HMI design detailed requirements and recommendations can be found in ISA-18.2 Clause 11 and guidance on advanced alarming techniques is provided in TR4.

Basic alarm design vs. enhanced and advanced alarm methods

This technical report, TR3, addresses basic alarm design while TR4 is focused on enhanced and advanced alarm methods. The purpose of this subclause is to provide clarity as to what methods and techniques are treated as basic alarm design vs. those that are treated as advanced alarm design. In general, basic alarm design principles should be applied first. In some cases though, such as dynamically changing processes (e.g., most batch processes), advanced techniques need to be considered up front. The use of advanced alarm design techniques typically carry with them added complexity and cost, and as such, are typically applied only when basic techniques are inadequate to address the necessary alarm functionality.

Purpose of this technical report

This technical report provides details on the basic alarm design process described in ISA-18.2 Clause 10. Following the lifecycle model shown in Figure 1, this report assumes that alarms to be addressed in basic alarm design have completed rationalization where attributes such as alarm setpoint and priority have been defined.