🔍 Key Concepts

• Fire behavior in ventilation ducts • Difference between preventive measures vs. firefighting response • How fuel, oxygen, and ignition relate to duct fires

💭 Think About

• Ask yourself which option changes the conditions inside the duct so a fire is less able to start or travel quickly. • Compare actions taken before a fire starts versus actions used after a fire is already burning. • Think about what actually allows a fire to move rapidly through a duct: is it the equipment sitting at the openings, the outside of the duct, or something inside the duct itself?

✅ Before You Answer

• Identify which options are mainly firefighting readiness (after ignition) versus true fire prevention (before ignition). • Consider where the fuel load for a duct fire would be located and which option directly reduces that fuel. • Verify which choice would most effectively limit fire spread along the duct’s length, not just help you fight it at an opening.