🔍 Key Concepts

• Flame screen location and purpose on cargo tanks, fuel tanks, and vents • Difference between vapor movement and flame propagation through openings or gauging devices • How gas-freeing, venting, and explosion protection are handled on tank vessels

💭 Think About

• Think about what a flame screen is trying to stop: is the main concern vapors moving, or a fire/explosion traveling? • Consider whether normal tank operations (loading, discharging, and breathing of tanks) require vapors to move in and out through vents. • Ask yourself: if vapors could not pass, what problems would that cause for a tank under changing temperature and pressure?

✅ Before You Answer

• Verify the primary function: prevent ignition from passing through an opening, not to seal gases completely • Confirm whether venting of vapors must still be allowed for safety of the tank structure • Check that the statement matches what you’d find on gooseneck vents, flame arresters, and P/V (pressure/vacuum) valves on tankers and fuel systems