🔍 Key Concepts

• Internal head pressure – what it means when fuel in the tank is pushing on the line by gravity • Fire protection goal – how to quickly stop fuel feeding a fire if the line is damaged • Location and type of valve required by towing vessel fire protection regulations (46 CFR, Subchapter M)

💭 Think About

• If the fuel line breaks below the tank, what happens to the fuel in each of these options? Which option most effectively stops gravity-fed fuel from continuing to flow? • Which kind of valve and location would let you shut off fuel right at the source without having to go into a burning or flooded space? • Think about the difference between a general "valve in the space" and a specifically required positive shutoff at the tank – which is more reliable in an emergency?

✅ Before You Answer

• Identify which choices clearly stop fuel flow at the tank outlet itself, not somewhere downstream in the system • Check which answer mentions a positive fuel shut-off rather than just any generic valve or drain • Verify in 46 CFR towing vessel fire protection rules that the valve must be located at the tank when the line is under internal head pressure