Which sequence describes a basic boiler emergency shutdown?

• A. Stop water feed only
• B. Stop fuel supply, close fuel valves, stop ash or air feed as required, trip burner control, open safety devices only as authorized, evacuate if needed and notify supervisor
• C. Increase fuel, open valves
• D. Keep burner running, ignore safety devices

Answer: (B)

In a boiler emergency shutdown, the priority is to quickly stop all sources that could keep the flame burning and to secure the system so it cannot re-ignite. The best sequence does this by first cutting off the fuel supply and closing fuel valves, which prevents any new fuel from being delivered to the burner. Then stop the ash or air feed as required to remove the reactant (air) that supports combustion. Next, trip the burner control to kill the flame and halt firing. Safety devices should be opened only as authorized when the situation requires it for protection, ensuring proper protection and record-keeping. If conditions threaten people or the plant, evacuate the area and notify the supervisor so responders can manage the incident.

This approach is why it’s the correct option: it rapidly isolates energy and extinguishes the flame, reducing the risk of fire, explosion, or damage. Stopping only the water feed doesn’t stop combustion and can cause other hazards. Increasing fuel or keeping the burner running while ignoring safety devices would worsen the danger.