Which device is required to prevent unwanted discharge in clean agent suppression systems?

• A. Valve lockout tag
• B. Relief valve
• C. Pressure gauge
• D. Emergency stop switch

Answer: (B)

In clean agent suppression systems, preventing unintended release hinges on controlling pressure automatically. A relief valve is installed to vent excess pressure if the system over-pressurizes, which can happen from thermal expansion, plant conditions, or a partial blockage. By opening at a predetermined set point, the relief valve prevents the pressure from forcing the agent into discharge paths or damaging components, thereby avoiding an unwanted discharge and keeping the system safe until the release sequence is deliberately initiated. Other devices don’t provide this automatic pressure-relief function: a lockout tag is an administrative control, a pressure gauge only measures pressure, and an emergency stop switch requires manual action and doesn’t prevent overpressure events.