Gas, LPG, Propane or Biogas solenoid valves are typically only be used with this fail-safe closed function. For instance in the event of a fire either the fire brigade or a health and safety officer will shut off all electrical power especially before trying to extinguish flames with high pressure water hoses. Additionally with power off and systems shut boiler and furnace flames could and need to be extinguished and therefore any gas supplied would simply be pumped into the surrounding atmosphere generating a very potentially explosive atmosphere. So you do not want your gas valves in the open position.
Some gas valve users ask for normally open gas solenoid valves, but in fact the majority of cases a manual reset solenoid valve is required.
Gas pressure: Gas solenoid valves slam shut isolation valves typically work from zero pressure up to typically 0.2 (200 millibar) and 0.5 (500 millibar) and gas supply systems are normally at a very low pressure measured in millibar.
pGas valve sizes: Typically available 1/8", 1/4", 3/8",1/2", 3/4",1",11/4",11/2" and 2" threaded ends with flanged PN16 sizes DN65, DN80, DN100, DN125, DN150, DN200, DN250 and DN300.
Gas valve materials: Typically Aluminium, miniature gas solenoid valves Brass and large flanged sizes from DN250 typically Cast Iron.