Last month’s article discussed the state of building automation system (BAS) alarming in many buildings, and it’s not good. Building operators are far too often saturated with alarms, and the intended purpose of alarming is lost. Many of these alarms are nuisance alarms, meaning they’re going off unnecessarily. One of the primary reasons for the high quantity of nuisance alarms is the lack of understanding of the concept of latching.
Alarms can be configured to generate when some unexpected condition is observed by a BAS. A latching alarm requires both the alarm condition to have gone away and acknowledgment from the building operator for it to be reset (i.e., go inactive). A non-latching alarm does not require such acknowledgement; if the alarm condition goes away, the alarm will automatically reset.