We specified solenoid valves for our ON/off valves to work with 120 VAC.  Some of these solenoid valves must operate in a classified area and require to be intrinsically safe.  The vendor says that is impossible to obtain intrinsically safe solenoid valves operating at 120 VAC.
An I.S. device typically draws only a few mW from the supply. The supply, which is usually through a barrier or galvanic isolator, is inherently incapable of delivering more than a fraction of the energy required to cause ignition, hence it is 'intrinsically safe'. The maximum amount of energy depends on the type of gas, but is never high enough to operate a normal solenoid valve. I have used hydraulic servo valves in I.S. circuits, but these draw tiny currents at limited voltages.
If you are designing or specifying equipment for a hazardous area then get help from someone who knows what they are doing. The questions you are asking demonstrate that you don't have sufficient knowledge to do this design to a competent level. There are the obvious safety implications of getting it wrong and under the European ATEX legislation both you personally and your employer are liable for the installation design. I am unsure what applies in the rest of the world.

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