API · ASME · DIN · EN standard industrial valves
Fixed Orifice Double Regulating Valves
Fixed orifice double regulating valves add a calibrated orifice to the double-regulating trim, so flow is read from the differential pressure across a fixed restriction — the manufacturer notes the integral fixed orifice offers greater accuracy than variable orifice designs, with easier set-up and fewer connections. The range covers a bronze PN25/PN16 line in DN15 to DN50 (including low-flow and ultra-low-flow variants) and ductile iron PN16 / Class 125 lines in DN65 to DN300, with BS EN 10226-2 (ISO 7-1) taper or BS 2779 (ISO 228) parallel threads on small sizes and flanged ends on ductile iron lines. Selection turns on the measurement accuracy the commissioning standard demands, the flow band (standard/low/ultra-low), and the end-connection standard of the pipework.
Part of the Balancing Valves family
Last updated: 2026-10
Family specifications
| bronze line | D931 DN15 to DN50 Fixed Orifice Double Regulating Valve (FODRV) – Bronze PN25 |
|---|---|
| low flow variant | D933 DN15 Low Flow Fixed Orifice Double Regulating Valve (FODRV) – Bronze PN16 |
| ultra low flow variant | D934 DN15 Ultra Low Flow Fixed Orifice Double Regulating Valve (FODRV) – Bronze PN16 |
| ductile ansi line | DA941 DN65 to DN300 Fixed Orifice Double Regulating Valve (FODRV) – Ductile Iron Class 125 |
| ductile pn16 line | DM941 DN65 to DN300 Fixed Orifice Double Regulating Valve (FODRV) – Ductile Iron PN16 |
| design principle | The integral fixed orifice design offers greater accuracy than the variable orifice design valves |
| end connections | taper threaded to BS EN 10226-2 (ISO 7-1) formerly BS 21 |
| end connections | End Connections Flanged |
| parallel threads | BS 2779 (ISO 228) parallel |
| body materials | Bronze, Ductile Iron |
| fv design focus | Single unit Y-pattern globe valve incorporating a fixed orifice plate flow measurement unit, with a pair of measuring plugs |
| fv measurement accuracy | +/-5% across all opening settings |
| fv design standard | BS 7350 |
| fv threaded connection | EN 10226-1 (ISO 7) taper thread |
| fv working pressure | 25 bar |
| fv shell test pressure | 37.5 bar (x1.5) |
| fv seat test pressure | 27.5 bar (x1.1) |
| fv application | Hydronic balancing of heating and cooling systems |
| fv temperature range | -10 deg C to 120 deg C |
| fv suitable medium | Water |
| fv body materials | Bronze |
| fv bonnet materials | DZR brass (DN15 to DN32), bronze (DN40 to DN50) |
| fv stem materials | DZR brass |
| fv disc materials | DZR brass (DN15 to DN20), DZR brass + PTFE (DN25 to DN50) |
| fv orifice insert materials | DZR brass |
| fv seal materials | EPDM (O-ring) |
| btt size range | DN65 to DN300 (WRAS approved); DN350 to DN600 (standard design) |
| btt operating pressure | 233 psi (16 bar) |
| btt design standard | BS EN 12334 |
| btt approvals | WRAS approved |
| btt end connections | PN16 flanged (BS EN 1092-2) |
| btt coating | Fusion bonded epoxy (FBE), RAL 5015 blue |
| btt body materials | Ductile iron with fusion bonded epoxy (FBE) coating |
| btt operation | Lockable handwheel with position indicator |
| btt applications | Potable water distribution and balancing, HVAC chilled and hot water circuits, mechanical service systems, pump circuit and equipment flow control, industrial process water regulation |
| ht design focus | Single unit Y-pattern globe valve with integral orifice plate forming a fixed orifice flow measurement unit, with regulation and isolation capacity |
| ht double regulating feature | Valve can be used for isolation and reopened to its pre-set position to maintain required flow rate |
| ht measurement accuracy | 5% accuracy class at all open positions in accordance with BS 7350: 1990 |
| ht design standard | BS 7350: 1990 |
| ht size range | DN65 to DN300 |
| ht nominal pressure | PN16 |
| ht temperature range | -10 deg C to 120 deg C |
| ht body materials | Ductile iron |
| fv size range | DN15, DN20, DN25, DN32, DN40, DN50 |
| fv kvs full open | Kvs (fully open): 2.2, 4.6, 8.5, 16.7, 26.1, 43.2 (DN15-DN50 order) |
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 materials are fixed orifice double regulating valves available in?
The published specification lists body materials: Bronze, Ductile Iron. Material availability for a specific size and rating is confirmed at quotation.
What end connections do fixed orifice double regulating valves support?
The published specification lists taper threaded to BS EN 10226-2 (ISO 7-1) formerly BS 21 as the available end connections. The connection for a specific size is confirmed at quotation.
What should a quotation inquiry for fixed orifice double regulating 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.
Request a quote for fixed orifice double regulating valves
Submit the requirement here — a quotation-ready inquiry states the governing standard and class, size, materials, medium, temperature and destination.
What happens to your details is described in our privacy notice.
Get a quotation for Fixed Orifice Double Regulating Valves
Send the standard, pressure class and size for a quotation-ready inquiry — answered with documents and terms.