Which layer of protection includes alarms that signal operators to take action before a trip or relief occurs?

• A. Alarms / operator action
• B. Normal automatic controls
• C. Tech Spec Limit
• D. Break point

Answer: (A)

In a multi-layer protection scheme, the alarms that prompt operators to take corrective action before a trip or relief occur belong to the alarms and operator action layer. This layer sits between the automatic controls and the automatic trip or relief actions. When normal automatic controls can’t fully maintain a parameter in the safe range, alarms alert the operators and give them a window to adjust, reduce risk, or intervene manually. If the operator action succeeds, the system stays in a safe state without triggering a trip. If not, the protective mechanism will eventually trip or relieve to bring the system to a safe condition. The Tech Spec Limit defines mandatory operating constraints rather than a human-in-the-loop alert, and Break point isn’t a standard protective layer here. So this alarms/operator action layer best fits the idea of signaling operators to take action before a trip or relief occurs.