Which of the following is an active safeguard?

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

Answer: (C)

Active safeguards are controls that automatically respond to process conditions to prevent a hazardous situation. A flow controller fits this because it continuously measures the process flow and automatically adjusts a valve or pump to keep the flow at the setpoint. This automatic, energy-powered action happens without needing operator input, actively maintaining safe conditions.

Nitrogen inerting can prevent hazards by displacing oxygen, but it’s typically a passive protective measure unless it’s part of an automatically controlled system. A check valve provides passive protection by preventing backflow and doesn’t react to changing conditions. An alarm system warns when something is off, but it usually requires human response to prevent a consequence, so it’s a detection/alert rather than an automatic protective measure.

So the flow controller stands out as the active safeguard because it actively maintains safe operation through automatic control.