Which of the following is employed as a safeguard against the hazards of flow?

• A. Check Valve
• B. Line Blank
• C. Gate Valve
• D. Pressure Transmitter

Answer: (A)

A check valve acts as a safeguard against flow hazards by automatically allowing fluid to move in only one direction and shutting off if flow tries to reverse. This prevents backflow, which can cause contamination, mixing of incompatible streams, pressure surges, or damage to equipment, all without needing any operator action. The other options don’t provide this automatic backflow protection: a gate valve controls or isolates flow but doesn’t inherently prevent reverse flow and can be bypassed, a pressure transmitter monitors conditions but doesn’t stop flow, and a line blank is an isolation method rather than a continuous anti-backflow safeguard.