What device is required on the vapor equalizing connection when the filling opening is 1 1/4 inch or larger?

• A. Emergency Shutdown Valve on vapor connection
• B. Backflow Check Valve
• C. Sealing Fitting
• D. Rain Cap

Answer: (A)

An Emergency Shutdown Valve on the vapor connection is required when the filling opening is 1 1/4 inch or larger because it provides a fast, reliable way to stop vapor flow if something goes wrong during filling. Larger openings increase the potential for rapid vapor release or a leak, so having an immediate shutoff helps isolate the system and prevent uncontrolled venting or overpressure. This safety feature gives the operator a quick means to halt the fill if a fault is detected or if a disconnect occurs.

The other options don’t fit this protection role. A backflow check valve prevents liquid from flowing backward into the supply line, which is a different kind of protection on the liquid side. A sealing fitting simply seals joints but does not provide a means to stop vapor flow in an emergency. A rain cap protects the vent from weather, but it doesn’t influence shutoff safety during filling.