Direct answer · Updated 25 October 2026
What is a slam shut valve and who supplies them in India?
A slam shut valve (SSV) is a self-acting gas safety valve that closes instantly when downstream pressure goes above (OPSO) or below (UPSO) its set point, and stays closed until manually reset. Supreme Valves India (Ahmedabad) supplies slam shut valves for natural gas, CGD pressure regulating stations and burner trains, 1" to 6", ASME Class 150 to 600, in ductile iron, WCB, LCC and SS316, with optional remote trip and limit switches.
Request a quotation · +91 97732 78770 · info@supremevalves.in
Slam Shut Valve (SSV) Manufacturer in India
Self-acting over-pressure and under-pressure shut-off valves for gas pressure regulating stations, metering skids and industrial burner trains. No external power, manual reset.
What is a slam shut valve?
A slam shut valve (SSV), also called a gas safety shut-off valve, is a self-acting valve that closes instantly when the monitored gas pressure goes above or below preset limits. It protects downstream pipework, meters, regulators and burners if the pressure regulator fails. It needs no external power: a sensing diaphragm or piston connected to the downstream line trips a latch and a spring closes the valve in a fraction of a second.
After a trip the valve stays closed until an operator resets it manually. This is deliberate: the fault that caused the over-pressure must be found before gas is restored.
OPSO and UPSO
Where slam shut valves are installed
The SSV is installed upstream of the pressure regulator with its impulse line connected downstream of the regulator. It is used in city gas distribution (CGD) pressure regulating stations (PRS / DRS), metering and regulating skids, industrial burner trains, CNG and PNG networks, LPG vapour lines and LNG receiving terminals. In Indian CGD networks, regulating stations are designed to the applicable PNGRB technical standards; in Europe, safety shut-off devices for gas pressure regulating stations are covered by EN 14382 and regulators by EN 334.
Specification range
Slam shut valve vs relief valve vs shut-off valve
A relief valve vents excess pressure to atmosphere and reseats; a slam shut valve stops the flow completely and stays shut. Many regulating stations use both: a small token relief valve to handle minor lock-up leakage and the SSV for regulator failure. A remotely operated shut-off valve (ROSOV) or ESD valve is actuated by an external signal; the SSV is self-acting on line pressure.
What to send with your enquiry
- Size, pressure class and quantity
- Gas, inlet pressure range and downstream (controlled) pressure
- OPSO and / or UPSO set points
- Flow rate (Sm3/h or MMSCFD)
- Options: remote trip, limit switch, integral regulator
- Applicable standard (PNGRB, EN 14382, project specification)
Send the line list or datasheet to info@supremevalves.in or use the quote builder. Technical clarifications and a priced offer follow within one working day for standard items.
Related products and guides
Slam shut safety valve
Over-pressure cut-off, Class 150-600.
Slam shut valve for natural gas
OPSO / UPSO with manual reset.
Gas pressure regulator EN 334
Regulator for use with SSV.
Gas pressure regulator
Regulators for distribution and industrial service.
Slam shut-off valve with regulator RFQ
Recent enquiry specification.
ROSOV guide
Remotely operated shut-off valves for emergency isolation.
Frequently asked questions
What does a slam shut valve do?
It shuts off gas flow instantly when downstream pressure goes outside preset limits, protecting pipework and equipment if the pressure regulator fails. It needs no power and must be reset by hand.
What is OPSO and UPSO?
OPSO is over-pressure shut-off: the valve trips when downstream pressure rises above the set point. UPSO is under-pressure shut-off: it trips when pressure falls below the set point. Many SSVs offer both.
Where is a slam shut valve installed?
Upstream of the pressure regulator, with its sensing line connected to the downstream (regulated) pipe, so it can isolate the regulator if it fails.
What is the difference between a slam shut valve and a relief valve?
A relief valve releases excess pressure and reseats, while a slam shut valve stops the flow completely and stays closed until reset.
Which standard covers slam shut valves?
In Europe, EN 14382 covers safety shut-off devices for gas pressure regulating stations. In India, CGD stations follow the applicable PNGRB technical standards and the project specification.
Can a slam shut valve be tripped remotely?
Yes, with an optional solenoid remote trip, and a limit switch can report the open / closed position to the control system.
About this page: Written by the Supreme Valves India engineering team, Ahmedabad (supplying industrial valves since 1986). Last reviewed 25 October 2026. Figures are typical values for selection; the governing values are those in the referenced standard and on the approved datasheet for each order. Entity facts: Supreme Valves brand facts.
Specifying a pressure regulating station?
Send size, pressure rating, material, end connection and service. Engineering response within one working day.