Which of the following is an example of an active safeguard?

• A. Flow Controller
• B. Nitrogen Inerting
• C. Alarm System
• D. Check Valve

Answer: (A)

Active safeguards are protective actions that automatically intervene to keep the process within safe limits, using energy or control action rather than relying on passive hardware or a human response. The flow controller fits this role because it continuously monitors the flow and automatically adjusts a valve to maintain the desired flow rate. This automatic feedback prevents unsafe conditions like overflows, incorrect mixing, or pressure fluctuations by responding to disturbances in real time.

Other options don’t embody this automatic control function as clearly. A check valve is a passive device that prevents backflow without sensing or adjusting anything. Nitrogen inerting helps reduce risk by maintaining an inert environment, but it doesn’t automatically regulate a process parameter in response to changes. An alarm system alerts when something is off but doesn’t itself change the process to bring it back to safe conditions unless an automatic or operator response kicks in.