🔍 Key Concepts

• How different extinguishing agents work to stop the fire triangle (heat, fuel, oxygen) • Surface cooling vs. smothering (oxygen removal) vs. separating fuel from oxygen • Which agents leave protection on the fuel after discharge, and which leave nothing behind

💭 Think About

• For each choice, ask: does this agent only remove heat, only displace oxygen, or also create a lasting barrier on the fuel? • Think about which agent dissipates quickly into the air without cooling the fuel very much, allowing hot surfaces to re-ignite when oxygen returns • Consider which agents are best for deep‑seated fires versus only for quick knockdown in a closed space

✅ Before You Answer

• Identify which agent is primarily an oxygen-displacing gas with little or no cooling effect • Decide which agents (water stream, water fog, foam, CO₂) can continue to cool or blanket the fuel after application stops • Ask yourself: after I stop applying this agent, which situation would most easily let flames come back if any ignition source remains?