B-1.1, r. 2 - Construction Code

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8.170. The piping of a tank installed at an elevation above the base of the motor fuel dispenser must have a solenoid check valve at the tank outlet that is designed to open only when the dispenser is being operated.
If the piping is connected to a submersible pump with a leak detection system, the solenoid check valve must be installed between the tank and the leak detection system.
O.C. 220-2007, s. 1.