We have seen ruptured gas lines that has caused explosions and building fires caused by earthquakes and also by other natural disasters. An example is the hurricane that hit the East Coast a few years ago and caused buildings to catch fire in the flooded areas.
The design of the emergency gas shutoff valve is based on the following: A gas line and gas meter is installed at a building with the right volume of gas capacity to feed the building for the devices that need the gas (furnace, dryer, stove,, etc.). The meter can provide more volume or flow than what the gas devices require. If another gas using device is added then another gas meter and gas line that can handle the higher volume must replace the old meter and line to accommodate the increased usage.
The emergency gas shutoff valve is designed to be set to the maximum volume or flow of the existing gas meter. The sensor in the shutoff valve monitors the flow of gas. For normal user conditions the gas flow is lower than the maximum flow that the gas meter is able to provide.
The emergency gas cutoff valve is placed between the gas meter and the gas pipe going into the building.
When the emergency gas shutoff valve senses that the flow coming out of it is equal to the maximum flow from the meter which was preset, then it will automatically close to prevent further flow into the building. This prevents gas flow and potential explosion and fire.
There is a manual reset button that pops ups and has a red color to indicate that the valve has closed. Also an optional communications system can be built into the unit to send a message of the valve being activated to the gas company and the location of the valve.
This emergency gas cutoff valve unit can also be used in underground gas lines that feed the buildings from the street. An additional circuitry added to the unit would allow the unit to be reset by remote control since it is buried in the ground.
The manufactures of gas meters can implement the designs into new gas meters. They already have built into new meters a system for reading the meters from the street for billing purposes. New electric meters that are installed already have the ability to send meter readings to the electric utility company. The same or similar technology can be used on gas meters to identify the emergency gas shutoff being activated.