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Revision of Annunciator Sequences and Specifications Standard

  • Standards

The ISA18 committee, Instrument Signals and Alarms, has reactivated a working group to revise ISA–18.1, Annunciator Sequences and Specifications, which was first published as an American National Standard in 1979 and then reaffirmed without change in 2004. The working group has started by working through comments from a prior revision draft from several years ago, from which it will determine if new content is needed—such as, perhaps, around the use of software annunciators.

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At one time, the most important alarms were found in annunciators, but the advent of computer monitor–based control systems in the 1980s and 1990s saw a major shift of most alarm window displays onto computer screens. This led to a downturn in sales of conventional alarm annunciator systems, with some supplier companies being sold off or going out of business. However, new annunciator panels have continued to be included in designs for a variety of reasons. In recent years, in fact, alarm annunciators have seen a resurgence in popularity—especially for use in IEC 61508 SIL 1 and safety, health, and environmental alarm-monitoring applications.

The ISA-18.1 working group plans to release an updated version for review within the ISA18 committee in the coming months, with the intent to complete the revised standard by the end of 2022. Individuals interested in participating are welcome and are asked to contact For more information on ISA18, visit

This update was provided by Bridget Fitzpatrick of Wood, who, with Cristobal Ruiz of Dow, is co-chairing the annunciator working group for ISA18. Fitzpatrick is a member of the ISA Standards & Practices Board, for which she serves as managing director of the ISA18 committee.

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