OEM manufacturer ASME B16.36 · ASME B1.20.1
Orifice Flanges — ASME B16.36
Orifice flanges are paired flanges with radial pressure taps, used to hold an orifice plate and measure the pressure drop across it for flow metering. Teshi Group manufactures orifice flanges to ASME B16.36 in weld neck, slip-on and threaded types, supplied as sets with jack screws.
Also called: orifice flange union, orifice flange set, flange tap orifice flange, metering flange
What is an Orifice Flange?
An orifice flange set clamps an orifice plate between two flanges. Each flange has pressure taps drilled radially through the rim, normally ½″ NPT, so a differential pressure transmitter can read the drop across the plate. The flanges are thicker than standard ASME B16.5 flanges to make room for the taps. Jack screws allow the flanges to be spread to remove and inspect the plate without disturbing the pipe. ASME B16.36 covers weld neck orifice flanges in Class 300 to 2500, and slip-on and threaded types in Class 300 only.
Key features
- Paired taps per flange, typically ½″ NPT; socket-weld taps on request
- Jack screws for plate removal
- Weld neck bore matched to pipe schedule for metering accuracy
- Supplied as sets with studs, nuts and gaskets on request
- RF or RTJ facing
Specification
| Supply | OEM manufacturer — Teshi Group, India |
|---|---|
| Standard | ASME B16.36; tap threads to ASME B1.20.1 |
| Size range | NPS 1″–24″ weld neck (Class 2500 to NPS 12″) |
| Pressure class | Weld neck: Class 300, 400, 600, 900, 1500, 2500; slip-on and threaded: Class 300 |
| Taps | Two ½″ NPT taps per flange as standard; socket-weld taps or other sizes on request |
| Facing | RF, RTJ |
| Materials — carbon steel | ASTM A105 / A105N; ASTM A181 Cl 60, Cl 70; ASTM A266 Gr 2, Gr 4 (large forgings) |
| Materials — high-yield carbon steel | ASTM A694 F42, F46, F48, F50, F52, F56, F60, F65, F70 (MSS SP-44 grades F52–F70) |
| Materials — low-temperature carbon steel | ASTM A350 LF1, LF2 Cl 1, LF2 Cl 2, LF3, LF6, LF9 |
| Materials — alloy steel (Cr-Mo) | ASTM A182 F1, F2, F5, F5a, F9, F11 Cl 1 / 2 / 3, F12 Cl 1 / 2, F21, F22 Cl 1 / 3, F22V, F91, F92, F911; ASTM A336 F11, F22 (large forgings) |
| Materials — stainless steel | ASTM A182 F304, F304L, F304H, F304LN, F309H, F310, F316, F316L, F316H, F316LN, F316Ti, F317, F317L, F321, F321H, F347, F347H, F348 |
| Materials — 904L and 6Mo | 904L (ASTM A182 F904L, UNS N08904); 254 SMO / 6Mo (ASTM A182 F44, UNS S31254); AL-6XN (ASTM A182 F62, UNS N08367) |
| Materials — duplex stainless steel | ASTM A182 F51 (UNS S31803), F60 (UNS S32205, 2205) |
| Materials — super duplex stainless steel | ASTM A182 F53 (UNS S32750, 2507), F55 (UNS S32760), F61 (UNS S32550) |
| Materials — nickel alloys | ASTM B564 / B160 / B462: Nickel 200 / 201 (N02200 / N02201), Monel 400 (N04400), Monel K-500 (N05500), Inconel 600 (N06600), Inconel 625 (N06625), Inconel 718 (N07718), Incoloy 800 / 800H / 800HT (N08800 / N08810 / N08811), Incoloy 825 (N08825), Hastelloy C276 (N10276), Hastelloy C22 (N06022), Hastelloy B2 / B3 (N10665 / N10675), Alloy 20 (N08020) |
| Materials — titanium | ASTM B381 Grade F1, F2, F5 (Ti-6Al-4V), F7, F12 |
| Materials — copper-nickel | Cu-Ni 90/10 (UNS C70600) and 70/30 (UNS C71500), ASTM B151 bar; flanges to ASME B16.5 or EEMUA 145 |
| Grade availability | Every grade listed is made or supplied against order, with EN 10204 3.1 certificates (3.2 / third-party inspection when specified) and PMI on alloy, stainless, duplex and nickel grades. |
| Testing | Visual and dimensional inspection, PMI on alloy and stainless grades, hardness; UT, MPI/DPI as specified |
| Documents | EN 10204 3.1 mill test certificate; 3.2 / third-party inspection when the order specifies; dimensional inspection report; IBR certification when specified |
Applications
- Natural gas and fuel gas metering
- Steam flow measurement
- Crude and product custody transfer runs
- Process flow measurement in refineries and chemical plants
- Water and utility flow metering
Technical data sheets
Dimensions & weights
FAQ
Orifice Flange: common questions
Which classes does ASME B16.36 cover?
Weld neck orifice flanges in Classes 300, 400, 600, 900, 1500 and 2500. Slip-on and threaded orifice flanges are covered in Class 300 only. Class 150 lines normally use Class 300 orifice flanges.
What tap size is standard?
Each flange normally has two ½″ NPT taps, placed opposite each other, so a set has four taps. Socket-weld taps or other sizes can be machined when the instrument specification requires.
Why do orifice flanges have jack screws?
Jack screws push the flanges apart so the orifice plate can be removed, inspected or changed without springing the pipe. Usually one jack screw is fitted to each flange, 180° apart.
Do I need to give the pipe bore?
Yes for weld neck orifice flanges. The bore must match the pipe ID exactly to avoid disturbing the flow profile, so state the pipe schedule or ID.
Need a size or grade not listed here?
Our engineering team manufactures against your drawing or datasheet, with dimensional sign-off before dispatch.
Send us your specificationTraceability
From mill heat to your site
- 01
Approved mill material
Received against the mill certificate; heat number registered.
- 02
Forging & machining
Heat number carried through every stage in our Indian works.
- 03
PMI, dimensional & NDT
Every lot inspected to the governing standard; TPI witness on request.
- 04
Stamped & certified dispatch
Hard-stamped pieces with EN 10204 3.1 / 3.2 certificates.
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