Pressure Reducing Valve Selection Guide for Steam and Air
Choosing a pressure reducing valve (PRV) or pressure regulating valve starts with duty: continuous downstream control, not overpressure relief. Supreme Valves India supplies self-actuating SV-PR, bellows-operated SV-BR and pneumatic SV-PN series from Ahmedabad.
1. Confirm it is a PRV, not a PSV
If the valve must hold a set outlet pressure during normal flow, specify a PRV. If it must open only when pressure exceeds a set limit to protect equipment, specify a safety relief valve such as Supreme SV-SR. Mixing these duties is a common specification error.
2. Map inlet, outlet and flow
Record maximum inlet pressure, required outlet pressure, minimum differential, flow rate and temperature. Self-actuating pilot-piston valves typically need adequate differential (SV-PR notes a minimum around 7 psig). Reduction ratios up to 20:1 are available on series designs; large cuts may need staging or an external balance line when outlet is below about 55% of inlet.
3. Pick the actuation family
4. Material and class
ASTM A216 WCB covers most steam utility lines. Move to CF8/CF8M or alloy steel for corrosive or higher temperature duty. Match flange class (150/300/600) to design pressure via ASME B16.34 practice.
5. Shut-off and trim
Pilot and main-valve guiding support tight shut-off. Steam often uses stellited or stainless trims. Air and non-corrosive gas can use non-metallic seats where dead-tight shut-off is required.
6. RFQ data that speeds a correct offer
- Fluid / state
- Flow rate
- Inlet pressure
- Outlet pressure
- Operating temperature
- Line size / end connection
- Fail position (SV-PN)
Send an RFQ
Frequently asked questions
What is the difference between a PRV and a PSV?
A PRV continuously regulates downstream pressure during normal flow. A PSV or safety relief valve opens only when pressure exceeds a set limit to protect equipment. See also PSV vs PRV difference guide.
When should I use a self-actuating PRV vs a pneumatic PRV?
Self-actuating PRVs suit many steam and air utility duties without instrument air. Pneumatic or motorized PRVs are used when remote setpoint, fail position or integration with a control system is required.
What data is needed on a PRV RFQ?
Fluid and state, flow rate, inlet and outlet pressure, temperature, line size and ends, and fail position for actuated models.