Glossary · HMI, SCADA and operations
Alarm shelving
Also known as: Shelving
German: Alarmunterdrückung
In alarm management, alarm shelving is a controlled, operator-initiated way to temporarily remove an alarm from the active alarm display, typically for a limited time and with the shelved alarm tracked and returned automatically.
- HMI and SCADA
- Process industry
In one sentence
Alarm shelving lets an operator temporarily remove a nuisance alarm from the display, with time limits and tracking.
Example
A level switch chatters because of foam; the operator shelves its alarm for eight hours, and the shelved alarms list shows it until maintenance repairs the switch.
How it applies
- Engineering: ISA-18.2 distinguishes shelving (operator-initiated, temporary) from suppression by design (logic-based, for example when equipment is out of service) and out-of-service alarms (removed for maintenance). Shelving should be time-limited, logged and restricted by Access level.
- Operation: A shelved alarm hides a real condition. Shift handovers should review the shelved alarms list.
- Documentation: State who may shelve which alarms, for how long, and how shelved alarms are reviewed. The German list term "Alarmunterdrückung" is broader (suppression); in German documents, distinguish "Zurückstellen" or "Shelving" if the system makes the distinction.
Alarm shelving vs. bypass
Shelving hides an alarm indication; the process logic keeps working. Bypassing a protective or safety function disables the protection itself, which is a different and much more serious action (see Bypass behavior).