What type of protection must be provided to ensure gas ceases to flow in case of a pull-away incident?

The correct provision to ensure that gas ceases to flow in the event of a pull-away incident is break-away protection. This safety feature is specifically designed to disconnect the fuel supply line from the fueling unit when a vehicle unintentionally drives away while still connected to the dispenser. The function of break-away protection is critical in preventing the release of fuel into the environment, which could lead to hazardous situations such as fires, explosions, or environmental contamination.

Break-away devices often incorporate a coupling system that allows for a clean separation without causing damage to the fueling equipment or the vehicle. Such safety measures are necessary in the design of CNG fueling stations and other fuel dispensing scenarios to enhance operational safety and mitigate risks effectively.

Other options, while also important in their respective contexts, do not directly address the immediate need to stop gas flow during a pull-away incident. Pressure relief valves serve to relieve excess pressure in the system, emergency shut-off switches allow for quick manual intervention in a variety of emergencies, and safety locks aid in securing equipment but do not function to immediately stop gas flow in the specific scenario of a pull-away. Therefore, break-away protection is the most relevant and effective measure for this particular situation.