Posted by: Harold Ennulat | October 31, 2010

Alarming Links & Resources

Alarming Standards

ANSI/ISA-18.2-2009 is becoming the basis for any new alarming work.  This standard was issued August, 2009 after 3 years of committe work.  An introduction to this standard can be found at: The table of contents can also be viewed here.  The full (aproximately 80 page) standard needs to be purchased from ISA.  ISA members can view the standard for free however.

Note that process levels are shown in the context of "normal" operating ranges to provide "information" instead of "data". click to show details.

Alarming Best Practices

A description of good and bad HMI alarming practices is presented by Bill Hollifield in a PowerPoint presentation that can be downloaded through TopPDF . It may also be available directly from his company’s web site at I found this presentation informative. It shows examples of using HMI’s to display “information” and not just “data”. The screens suggested are getting grayer with much less color. This is so that color can be used to show abnormal conditions and alarm conditions.

Using "breadcrumbs" to indicate alarms. click to enlarge

PAS has also published a handbook based on the ISA 18.2 standard that details their view of HMI alarm managagment best practices.

Rockwell also has a presentation on Alarm Management best practice at For example, the screen on the left shows “breadcrumbs” or small indicators that light up in red or yellow with a small symbol to indicate trouble or an alarm.

Best Practice Organizations - click to enlarge

Additional Resources for best practices are depicted in the graphic on the right.

Alarm Rationalization

I ran across this link on Alarm Rationalization:

There is a LinkedIn discussion on Alarm Rationalization in the Alarm Management Group. One commentator summarized it this way:

A worthwhile alarm rationalization requires 40% expertise and 60% elbow grease. 

After having performed the task on several recent power plant control upgrades, totaling 20,000+ wired I/O, I can tell you:

– The ANSI/ISA-18.2-2009 standard is our first viable non-commercial guideline. Get it, read it, and use it to defend your alarm philosophy and alarm guideline compliance.
– Rationalization is rare since process stakeholders seldom evangelize to management in a manner that wins the needed resource allocation.
– Avoiding one “event” pays for a high-performing alarm system.
– Textbook rationalization involving operations, engineering, and technical resources is not likely to occur. The effort may start but will not be sustained since the resources get yanked back to their “day jobs”.
– Alarm rationalization is like accounting. It requires focus, expertise, and is best left to dedicated professionals.

Richard Marshall, P.E.

LinkedIn Groups


Updated: October 22, 2010 11:30 am | for Publishing October 31, 2010

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