At most sites, the alarms are specified by project teams that design the systems but will never have to operate them. After commissioning, the system is then turned over to operators who are not intimately familiar with every facet of its design. Both sides tend to favor “more information” at design time. Once the system is turned over, these alarms become nuisances that do more to hinder operations than they do to streamline them.

At some point, there is an alarm remediation effort where a lot of smart people work really hard to get a handle on the problem; but getting teams to agree on what should get deleted can quickly become impossible.

ISA 18.2 provides a solution. It isn’t a quick and easy solution, but rather a paradigm and process for developing and refining alarm systems. The standard itself is relatively brief and readable, and there is an abundance of training resources online. Some important ideas that the standard promotes are:

• That each alarm must represent an unusual and actionable situation that must be responded to with some urgency, or some negative consequence will occur. The identification of these criteria is called “rationalization” and is guided by a site-specific document called an “alarm philosophy”.
• The criteria for the alarms should be persisted in some kind of central data store that is subject to a change control process.
• The system should undergo periodic audits and assessments.

The periodic audits should ensure that rationalization and change control occur. The assessments should determine how often the alarm interface is more obstructive than it is instructive, due to alarm chatter, flood, or other conditions. Ideally, the assessments would also be able to work with site operations teams to identify any recent negative events in order to ensure that they were captured by a single instructive and valuable alarm.

In the context of the growing interest in Fault Detection and Diagnostics (FDD), it is particularly important for HVAC automation systems to implement an alarm management approach that is inspired by ISA 18.2. It is very common for FDD criteria to be presented to operators through the same interface (and as a result, often with the same urgency) as the site alarms. A periodic review of the user experience for a facilities operator using the alarm system should have immediate value.