API · ASME · DIN · EN standard industrial valves
Pressure Reducing Valves
Valves that hold a stable downstream pressure below upstream pressure in steam, water and utility networks.
Last updated: 2026-10
Family specifications
| size range | DN20 to DN400 |
|---|---|
| pressure class | PN16 to PN64, ANSI Class 150 to Class 2500 |
| body materials | WCB (ASTM A216), CF8, CF8M (ASTM A351), F316, F316L (ASTM A182), F51/2205 duplex (ASTM A182), F11, F22 (ASTM A182), GG25 cast iron (EN 1561), GGG40, GGG50 ductile iron (EN 1563), C95400, C95800 aluminium bronze (ASTM B148), C83600, LG2 bronze (ASTM B62), CW617N, DZR brass (EN 12165) |
| temperature range | -10 to 70°C (direct-acting, water), 0 to 80°C (200X, water) |
| end connections | Flanged (EN 1092) |
| design standards | ASME B16.34 |
| testing standards | API 598 |
| designs | Direct Acting, Steam, Water, Pilot Operated, Pressure Relief and Sustaining, Float Control |
| accuracy behaviour | For pilot-operated steam regulators, set pressure is more stable and varies only a few percent over the full flow range. |
| internals material example | Benchmark pilot-operated steam regulators use all stainless steel internals for high-pressure applications up to 450 PSIG. |
| seat hardness example | Hardened stainless steel seat and disc (55 Rc). |
| size capacity example | Benchmark pilot-operated steam segment: sizes 1/2" to 4", NPT or 150/300 flanged connections, PMO 20 to 450 PSIG, steam capacity to 83,300 lbs/hr. |
| operating principle | A pilot-operated regulator uses a pilot (a small regulator) that senses the outlet pressure and controls the main valve through a pilot line, modulating the pressure on one side of the main valve actuator so the valve opens or closes to maintain the set pressure. |
| selection guidance | Direct-acting regulators suit small-scale applications for their simplicity and cost; pilot-operated regulators serve harsh industrial environments where high flow rates are required. |
| droop definition | Pressure droop is the reduction in the controlled outlet pressure of a pressure reducing regulator as the flow rate increases — an intrinsic characteristic of the internal force-balance mechanism, not a malfunction. Because the regulator is proportional-only in control, the outlet pressure must decrease slightly to re-establish force balance as flow rises; the setpoint is defined at a very low flow rate, just outside the lockup zone. |
| droop mitigation | Droop is reduced by a larger body size with higher Cv capacity, flexible composition diaphragm material, the largest available port size, softer and longer range springs, or pressure-loaded (dome-loaded) designs; pilot-operated regulators with integral "reset" action eliminate steady-state droop altogether. |
| droop typical value example | Benchmark dome-loaded regulator capacity tables are based on 95% accuracy (2 psi minimum droop). |
| pilot setpoint accuracy | Pilot-operated steam regulators hold secondary set pressure within ±0.01 MPa, maintained even when steam load or primary pressure at the valve changes. |
| pilot steam line envelope | Pilot-operated steam line example envelope: PMO 250 psig, TMO 428°F, primary pressure 30-250 psig, secondary pressure 5-210 psig, max flow capacity 47,380 lb/h, cast iron (FC250) body. |
| pilot droop quantified | Pilot-operated regulators: the fall in downstream pressure from fully open to fully closed is typically less than three hundredths of a bar (3 kPa; 0.5 psi). |
| pilot capacity vs direct | A pilot-operated pressure reducing valve will usually be smaller than a direct acting valve of the same capacity. |
| hydronic prv body materials | Hydraulic pilot-operated PRV body and cover material options: ductile iron, cast steel, or bronze. |
| hydronic prv trim materials | Trim (disc guide, seat, cover bearing): bronze standard, stainless steel optional. |
| hydronic prv stem spring | Stem, nut and spring: stainless steel. |
| hydronic prv check feature | With an added check feature, a pressure reversal admits downstream pressure into the main valve cover chamber, closing the valve to prevent return flow. |
| hydronic parallel station | Wide-range reducing stations use two pilot-operated reducing valves in parallel: the larger valve meets peak loads while the smaller handles low flows; a downstream pressure relief valve is recommended for such stations. |
| pilot drip tight closure | When downstream pressure exceeds the control pilot setting, the main valve and pilot valve close drip-tight. |
| anti cavitation trim | Anti-cavitation trim variants exist for high-differential duty: they provide optimum downstream pressure control while reducing cavitation noise and damage, and candidacy is screened with a cavitation guide/chart. |
Ordering & documentation
Documents
Ask for the documentation set with the inquiry — typical items (material certificates, test reports to the listed inspection standard, dimensional drawings) are confirmed and supplied with the quotation.
Quotation
Send the medium, temperature, pressure, size and connection for a quotation-ready inquiry. Lead time, MOQ and price are confirmed at quotation, together with the documents to be supplied with the order.
Sample & supply
Supply terms, order quantities and lead time are agreed per order — state the destination country and required schedule with the inquiry.
Storage & shipping
Store valves with seats and seals protected from UV, ozone and deformation, and keep end-face protectors on until installation; storage limits and shipping arrangements for the selected materials are confirmed at quotation.
Frequently asked questions
What standards govern the design and testing of pressure reducing valves?
The published specification for this family lists ASME B16.34 as the design standards. Testing follows API 598.
What sizes and pressure ratings are available for pressure reducing valves?
The published size range is DN20 to DN400, and the published pressure ratings are PN16 to PN64, ANSI Class 150 to Class 2500. Availability of a specific size and rating is confirmed at quotation.
What materials are pressure reducing valves available in?
The published specification lists body materials: WCB (ASTM A216), CF8, CF8M (ASTM A351), F316, F316L (ASTM A182), F51/2205 duplex (ASTM A182), F11, F22 (ASTM A182), GG25 cast iron (EN 1561), GGG40, GGG50 ductile iron (EN 1563), C95400, C95800 aluminium bronze (ASTM B148), C83600, LG2 bronze (ASTM B62), CW617N, DZR brass (EN 12165). Material availability for a specific size and rating is confirmed at quotation.
What working temperature range do pressure reducing valves cover?
The published working temperature range is -10 to 70°C (direct-acting, water), 0 to 80°C (200X, water). For a medium at the edge of the range, confirm the suitability of the selected seat and body materials at quotation.
What end connections do pressure reducing valves support?
The published specification lists Flanged (EN 1092) as the available end connections. The connection for a specific size is confirmed at quotation.
What should a quotation inquiry for pressure reducing valves include?
The governing standard and class, nominal size, body and seat materials, the service medium with temperature, and the destination — anything missing is confirmed during quotation.
Types in this family
Type
Direct Acting Pressure Reducing Valves
Direct acting pressure reducing valves balance downstream pressure against a setting spring in a single compact body, so no pilot line or external sensing is ne
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Pilot Operated Pressure Reducing Valves
Pilot operated pressure reducing valves let downstream pressure act on a large diaphragm through a small pilot valve, so a compact body modulates high flows wit
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Steam Pressure Reducing Valves
Steam pressure reducing valves drop live or saturated steam from a high-pressure header to the steady lower pressure that equipment, tracing and heating station
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Water Pressure Reducing Valves
Water pressure reducing valves hold a fixed downstream pressure in building supply, fire-protection and distribution networks, protecting fixtures and meters fr
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Pressure Relief / Sustaining Valves
Pressure relief / sustaining valves guard upstream pressure: a normally-closed pilot senses the inlet line, the main valve stays closed while upstream pressure
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Float Control Valves
Float control valves open and close on the level a float pilot reports from the tank, filling reservoirs and break-pressure cisterns to a set line and shutting
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Surge Anticipator Valves
Surge anticipator valves are pilot-controlled diaphragm valves that open on a pressure-rise transient and dump the surge to atmosphere or return line before it
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