Question 7: What are the requirements for quick-release connection and refueling hoses at hydrogen filling stations?

Answer: The quick-release filling connection must comply with the requirements of the ČSN EN ISO 17268 standard “Hydrogen gas – interface filling stations for land vehicles”. It must be able to detect overpressure. Hoses, that provide a conductive connection to the mobile device can be used for filling only. These hoses must withstand the flow of hydrogen at its operating pressure. The filling hose should not be shorter than 3 m and longer than 5 m. The design of the filling quick-release connection excludes its use for other purposes, except for filling the tanks of hydrogen mobile devices. The quick-release coupling allows filling only if it is tightly and correctly connected to the counterpart of the filled vehicle gas tank, preventing its unintentional disconnection. The quick-release coupling can only be disconnected after the pressure has been released. If the mechanical stress, applied to the filling hose, exceeds a certain limit, the quick-release coupling mechanism will mechanically disconnect itself from the counterpart of the filled tank, the hydrogen supply will be shut off, and the filler neck of the vehicle will also be automatically closed. The force required to automatically disconnect the filling device is significantly lower than the breaking strength of the filling hose itself or the force required to damage a quick-release coupling or the filling device. The filling hose has a certain electrical conductivity. This circumstance is necessary to bring the filling station and the vehicle to the same potential, thereby preventing the possibility of ignition due to a voltage jump.