Gas Solenoid Valve: Selection, Working Principle & Applications
A gas solenoid valve is an electromechanically actuated shut-off and control valve that uses a solenoid coil to open or close the flow path for combustible and inert gases. It is the standard choice for automated gas shut-off on natural gas, LPG, medical air, and inert gas lines where remote or safety-interlocked control is required.
How a Gas Solenoid Valve Works
When the coil is energised it builds a magnetic field that lifts the plunger against a spring, opening the orifice; de-energising lets the spring return the plunger to the closed seat. This simple on/off action makes the device ideal for interlock and emergency-stop duty. For background on the broader family, see our pneumatic valve solenoid guide.
Normally Closed vs Normally Open
A normally closed (NC) gas solenoid valve stays shut when de-energised and opens on power — the safe default for fuel gas, because a power loss closes the line. A normally open (NO) valve is used where flow must continue during a power loss. For most gas safety applications NC is specified.
Direct-Acting vs Pilot-Operated
Direct-acting valves shift the seat directly with the plunger and suit small orifice sizes and low flow. Pilot-operated valves use line pressure to assist seating and handle larger flows but need a minimum differential pressure to function. Selection detail is covered in our solenoid valve selection guide.
Gas Media Compatibility
- Natural gas / town gas: requires a soft sealing material compatible with dry gas and an explosion-protected coil where specified by local installation rules.
- LPG (propane/butane): needs NBR or FKM seals rated for liquid and vapour phases.
- Medical oxygen / air: demands oxygen-clean body materials and grease-free assembly.
- Inert gases (N2, argon, CO2): the widest material tolerance, often anodised aluminium or brass.
Selection Checklist
- Pressure range: match the valve’s maximum working pressure and minimum operating differential.
- Orifice / Cv: size from required flow at line pressure, not just pipe size.
- Voltage: 24 V DC and 220 V AC are common; confirm coil class for the control panel.
- IP rating: IP65 minimum for panel-mount, higher for washdown or outdoor duty.
- Body material: brass for general gas, stainless for corrosive or oxygen service.
- Leakage class: specify bubble-tight sealing for fuel and medical gas.
Typical Applications
Gas solenoid valves appear in boiler and burner control, laboratory gas lines, packaging machine inert-gas purging, analytical instruments, and automated safety shut-off on industrial gas trains. They are frequently paired with a pneumatic valve in hybrid fluid-power systems.
Safety & Compliance Notes
Gas solenoid valves are safety components. Specify bubble-tight seating, fit a manual isolation upstream, and verify coil protection matches the installation environment. Carroland manufactures to an ISO 9001:2015 quality system and supplies dimensional and test data to support customer compliance filing; purchasers remain responsible for local gas-code approvals.
Frequently Asked Questions
What is a gas solenoid valve used for?
A gas solenoid valve provides automated, electrically controlled on/off control of combustible or inert gas flow, most often for safety shut-off, burner control, and interlocked purge lines.
Should I use normally closed or normally open for gas?
Normally closed is the default for fuel gas: a power loss or emergency stop closes the line. Normally open is only chosen where flow must persist during a power outage.
Can a standard air solenoid valve handle natural gas?
Not by default. Gas service requires media-compatible seals, a suitable coil protection class, and bubble-tight seating; use a valve explicitly rated for the target gas.
What voltage do gas solenoid valves use?
Common coil voltages are 24 V DC and 220 V AC, selected to match the control panel supply. Confirm the coil protection class for the installation zone.
How do I size a gas solenoid valve?
Size from required flow and line pressure using the orifice/Cv, then confirm maximum working pressure, minimum differential pressure, and seal material for the gas media.