Nipoflange
Nipoflange : Specifications | Materials | Types | Dimensions | Weight Chart | Tolerances | FAQ
Reliable source for ASME B16.5 Nipoflanges in carbon, stainless, alloy, and high-nickel steels. We offer ½″–24″ sizes and 150#–2500# pressure classes, perfect for high-pressure pipelines in energy, chemical, and process industries.
Best Export Prices: sales@midlandforgefittings.com
Midland Forge and Fittings Pvt. Ltd. is a dedicated manufacturer and exporter of high-quality Nipoflanges designed for demanding piping applications. Based in India, we specialize in producing ASME B16.5 compliant Nipoflanges in carbon steel, stainless steel, alloy steel, and high-nickel alloys.
Our modern forging shop, CNC machining units, and in-house testing facilities allow us to control every stage of production—from raw-material inspection to final dispatch—ensuring consistent quality and on-time delivery to clients across oil & gas, petrochemical, power generation, and process industries worldwide.
The company follows a quality-first, customer-centric policy guided by international standards and ISO-aligned procedures. Each Nippoflange undergoes rigorous dimensional checks, non-destructive testing, and third-party inspection as required. We emphasize transparent sourcing, ethical business practices, and full material traceability to maintain long-term trust with EPC contractors, distributors, and end users. By combining advanced technology, skilled professionals, and a responsive service team, Midland Forge and Fittings Pvt. Ltd. delivers reliable Nipoflange solutions that meet critical project specifications while supporting sustainable and safe manufacturing practices.
A Nipo flange is a forged piping fitting that combines a Nipolet branch connection with a flanged end, providing a convenient bolted connection for valves, instruments, or auxiliary lines. It is designed according to ASME B16.48 standards for seamless integration with industrial piping systems.
Nipoflanges are available in carbon steel, stainless steel, alloy steel, and high-nickel alloys. The branch is butt-welded to the header pipe, ensuring smooth stress distribution, while the flange end—Raised Face (RF), Flat Face (FF), or Ring Type Joint (RTJ)—matches standard mating equipment for reliable sealing.
Ideal for high-pressure, high-temperature, and corrosive environments, Nipoflanges are widely used in oil & gas, petrochemical, power, and industrial piping systems. Their single-piece construction ensures strength, leak integrity, and precise dimensions, reducing installation time and enhancing operational safety.
Nipo Flange Specifications
Nipoflange – Materials, Grades & Standards
| Material Category | Standards / Grades (ASTM / ASME) | Pressure Class / Size Range | Typical Use / Application |
|---|---|---|---|
| Stainless Steel | ASTM A182 F304 / F304L / F304H | Class 150 – 2500, Size ½”–48” | General purpose, corrosion-resistant piping |
| ASTM A182 F316 / F316L / F316H | Class 150 – 2500, Size ½”–48” | Chemical, marine, food & pharma industries | |
| ASTM A182 F321 / F321H | Class 150 – 1500, Size ½”–24” | High temperature, stabilized service | |
| Carbon Steel | ASTM A105 (Forged CS) | Class 150 – 2500, Size ½”–48” | Pressure piping, oil & gas, general industries |
| ASTM A350 LF2 (Low Temp CS) | Class 150 – 1500, Size ½”–24” | Cryogenic & low temperature applications | |
| Alloy Steel | ASTM A182 F11 / F22 (Cr-Mo) | Class 150 – 2500, Size ½”–24” | Power plants, refineries, steam pipelines |
| ASTM A182 F91 | Class 150 – 2500, Size ½”–24” | High-temperature, power generation | |
| Duplex / Super Duplex | ASTM A182 F51 / F53 / F55 / F60 (UNS S31803 / S32205 / S32750 / S32760) | Class 150 – 2500, Size ½”–24” | Offshore, seawater, high corrosion service |
| Nickel Alloys | ASTM B564 Inconel 600 / 625 / 718 | Class 150 – 2500, Size ½”–24” | Heat exchangers, chemical, aerospace |
| ASTM B564 Monel 400 / K500 | Class 150 – 2500, Size ½”–24” | Marine, seawater handling, pumps | |
| Copper Nickel | ASTM B151 / B467 (Cu-Ni 90/10, 70/30) | Class 150 – 600, Size ½”–24” | Shipbuilding, desalination, seawater systems |
| Titanium | ASTM B381 Gr. 2 / Gr. 5 | Class 150 – 600, Size ½”–12” | Aerospace, seawater, lightweight piping |
| Aluminium | ASTM B247 6061 / 5083 | Class 150 – 300, Size ½”–12” | Lightweight, non-corrosive, low-pressure piping |
ANSI/ASME B16.5 Nipoflange – Dimensions
Nipoflange Weight Chart
| Size In Inches | Size in Millimeter | Height Of A | Outside Daimeter -B | Hole Daimeter C | Weight in Kilogram |
|---|---|---|---|---|---|
| 1/4 | 8 | 14.3 | 25.4 | 15.9 | 0.04 |
| 3/8 | 10 | 19.05 | 31.75 | 19.05 | 0.07 |
| 1/2 | 15 | 19.05 | 34.93 | 23.81 | 0.08 |
| 3/4 | 20 | 22.23 | 44.45 | 30.16 | 0.11 |
| 1 | 25 | 26.99 | 53.98 | 36.51 | 0.23 |
| 1 1/4 | 32 | 31.75 | 65.09 | 44.45 | 0.36 |
| 1 1/2 | 40 | 33.34 | 73.03 | 50.8 | 0.45 |
| 2 | 50 | 38.1 | 88.9 | 65.09 | 0.79 |
| 2 1/2 | 65 | 41.28 | 103.19 | 76.2 | 1.13 |
| 3 | 80 | 44.45 | 122.24 | 93.66 | 1.81 |
| 3 1/2 | 90 | 47.63 | 142.88 | 112.71 | 2.5 |
| 4 | 100 | 50.8 | 152.4 | 120.65 | 2.86 |
| 5 | 130 | 57.15 | 179.3 | 141.29 | 4.65 |
| 6 | 150 | 60.33 | 215.9 | 169.86 | 6.44 |
| 8 | 200 | 69.85 | 263.53 | 220.66 | 10.66 |
| 10 | 250 | 77.79 | 322.26 | 274.64 | 17.69 |
| 12 | 300 | 85.73 | 377.83 | 325.44 | 26.76 |
| 14 | 350 | 88.9 | 409.58 | 357.19 | 29.94 |
| 16 | 400 | 93.6 | 463.55 | 407.99 | 34.02 |
| 18 | 450 | 96.84 | 520.7 | 458.79 | 44 |
| 20 | 500 | 101.6 | 571.5 | 508 | 53.52 |
| 24 | 600 | 144.5 | 717.5 | 609.6 | 101 |
| 26 | 650 | 155.6 | 778 | 660.4 | 120 |
| 30 | 750 | 174.6 | 893.6 | 762 | 190 |
| 36 | 900 | 206.4 | 1070 | 914.4 | 310 |
| 40 | 1000 | 225.4 | 1187.6 | 1016 | 435 |
| 42 | 1050 | 235 | 1244.6 | 1066.8 | 540 |
| 48 | 1200 | 241.3 | 1404 | 1219.2 | 750 |
| Schedule 160 | |||||
|---|---|---|---|---|---|
| Size In Inches | Size in Millimeter | Height Of – A | Outside Daimeter – B | Hole Diameter – C | Weight in Kilogram |
| 1/2 | 15 | 28.58 | 34.93 | 14.29 | 0.11 |
| 3/4 | 20 | 31.75 | 44.45 | 19.05 | 0.32 |
| 1 | 25 | 38.1 | 50.8 | 25.4 | 0.38 |
| 1 1/4 | 32 | 44.45 | 61.91 | 33.34 | 0.57 |
| 1 1/2 | 40 | 50.8 | 69.85 | 38.1 | 0.79 |
| 2 | 50 | 55.56 | 80.96 | 42.86 | 0.97 |
| 2 1/2 | 65 | 61.91 | 96.84 | 53.98 | 1.53 |
| 3 | 80 | 73.03 | 120.65 | 73.03 | 2.87 |
| 4 | 100 | 84.14 | 152.4 | 98.43 | 4.76 |
| 5 | 130 | 93.66 | 187.33 | 122.24 | 6.46 |
| 6 | 150 | 104.78 | 220.66 | 146.05 | 12.7 |
| 8 | 200 | 111.12 | 284.16 | 173.04 | 20.41 |
| 10 | 250 | 125.41 | 312.74 | 215.9 | 38.56 |
| Schedule XS | |||||
| Size In Inches | Size in Millimeter | Height Of – A | Outside Daimeter – B | Hole Diameter – C | Weight in Kilogram |
| 1/4 | 8 | N/A | 25.4 | 15.88 | 0.05 |
| 3/8 | 10 | N/A | 31.75 | 19.05 | 0.07 |
| 1/2 | 15 | 19.05 | 34.93 | 23.81 | 0.09 |
| 3/4 | 20 | 22.23 | 44.45 | 30.16 | 0.14 |
| 1 | 25 | 26.99 | 53.98 | 36.51 | 0.21 |
| 1 1/4 | 32 | 31.75 | 65.09 | 44.45 | 0.41 |
| 1 1/2 | 40 | 33.34 | 73.03 | 50.8 | 0.5 |
| 2 | 50 | 38.1 | 88.9 | 65.09 | 0.79 |
| 2 1/2 | 65 | 41.28 | 103.19 | 76.2 | 1.18 |
| 3 | 80 | 44.45 | 122.24 | 93.66 | 1.86 |
| 3 1/2 | 90 | 47.63 | 136.53 | 112.71 | 2.54 |
| 4 | 100 | 50.8 | 152.4 | 120.65 | 2.9 |
| 6 | 150 | 77.79 | 225.43 | 169.86 | 10.43 |
| 8 | 200 | 98.43 | 292.1 | 220.66 | 16.78 |
| 10 | 250 | 93.66 | 323.85 | 265.11 | 20.87 |
| 12 | 300 | 103.1 | 379.41 | 317.5 | 27.67 |
| 14 | 350 | 100.01 | 431.8 | 350.84 | 31.75 |
| 16 | 400 | 106.36 | 466.73 | 403.23 | 46.27 |
| 18 | 450 | 111.13 | 523.88 | 455.61 | 58.97 |
| 20 | 500 | 119.06 | 582.61 | 509.59 | 71.67 |
| 24 | 600 | 152.4 | 722.2 | 609.6 | 142 |
| 26 | 650 | 165.1 | 782.6 | 660.4 | 168 |
| 30 | 750 | 181 | 896.8 | 762 | 218 |
| 36 | 900 | 212.7 | 1074.4 | 914.4 | 404 |
| 40 | 1000 | 235 | 1194 | 1016 | 582 |
| 42 | 1050 | 244.5 | 1250.8 | 1066.8 | 590 |
| 48 | 1200 | 273 | 1425.6 | 1219.2 | 910 |
| Schedule XXS | |||||
| Size In Inches | Size in Millimeter | Height Of – A | Outside Daimeter – B | Hole Diameter – C | Weight in Kilogram |
| 1/2 | 15 | 28.58 | 34.93 | 14.29 | 0.11 |
| 3/4 | 20 | 31.75 | 44.45 | 19.05 | 0.32 |
| 1 | 25 | 38.1 | 50.8 | 25.4 | 0.38 |
| 1 1/4 | 32 | 44.45 | 61.91 | 33.34 | 0.57 |
| 1 1/2 | 40 | 50.8 | 69.85 | 38.1 | 0.79 |
| 2 | 50 | 55.56 | 80.96 | 42.86 | 0.97 |
| 2 1/2 | 65 | 61.91 | 96.84 | 53.98 | 1.53 |
| 3 | 80 | 73.03 | 120.65 | 73.03 | 2.87 |
| 4 | 100 | 84.14 | 152.4 | 98.43 | 4.76 |
| 5 | 130 | 93.66 | 187.33 | 122.24 | 6.46 |
| 6 | 150 | 104.78 | 220.66 | 146.05 | 12.7 |
| 8 | 200 | 111.12 | 284.16 | 173.04 | 20.41 |
| 10 | 250 | 125.41 | 312.74 | 215.9 | 38.56 |
Nipoflange Tolerances as per ANSI / ASME B16.5,16.47
| Parameter | Size / Condition | Tolerance |
|---|---|---|
| Outside Diameter (O.D.) | ≤ 24 | ± 1.6 mm |
| Outside Diameter (O.D.) | > 24 | ± 3.2 mm |
| Counterbore Diameter | All Sizes | Not Applicable |
| Inside Diameter (I.D.) | All Sizes | Not Applicable |
| Length thru Hub | ≤ 18 | + 3.2 mm / – 0.8 mm |
| Length thru Hub | ≥ 20 | + 4.8 mm / – 1.6 mm |
| O.D. of Hub | ≤ 12 | + 2.4 mm / – 1.6 mm |
| O.D. of Hub | ≥ 14 | ± 3.2 mm |
| Thickness (Thick.) | ≤ 18 | + 3.2 mm / – 0 |
| Thickness (Thick.) | ≥ 20 | + 4.8 mm / – 0 |
| Drilling – Bolt Circle | All Sizes | ± 1.6 mm |
| Drilling – Bolt Hole Spacing | All Sizes | ± 0.8 mm |
| Eccentricity of Bolt Circle w.r.t Facing | ≤ 2½ | Max 0.8 mm |
| Eccentricity of Bolt Circle w.r.t Facing | ≥ 3 | Max 1.6 mm |
| Contact Face Diameter – 1.6 mm Raised Face | All Sizes | ± 0.8 mm |
| Contact Face Diameter – 6.35 mm Raised Face / Tongue & Groove / Male-Female | All Sizes | ± 0.4 mm |
What is a Nipoflange and how does it differ from a Weldolet?
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A Nipoflange is a branch fitting that combines a welded branch connection with a flanged end, allowing a branch line to be connected directly to valves, instruments, or other piping equipment.
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Differences from Weldolet:
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Weldolet provides a welded branch outlet only, whereas Nipoflange adds a flanged end, enabling bolted connections.
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Nipoflanges reduce the need for additional flanges or adapters at the branch, simplifying installation.
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Weld stress distribution is improved because the hub is forged and butt-welded, similar to Weldolets.
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How are Nipoflanges installed, and what are the critical considerations?
- Installation involves butt-welding the hub to the run pipe and then bolting the flanged end to the branch pipe or equipment.
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Critical points:
- Alignment: Ensure flange faces are parallel to prevent leakage.
- Welding Quality: Hub-to-pipe welds must follow ASME welding codes (ASME Section IX) to maintain structural integrity.
- Bolt Torque: Bolting should follow recommended torque specifications for the pressure class to avoid flange deformation.
- Inspection: Perform dimensional verification, NDT (radiography or dye penetrant), and hydrostatic testing where required.
How do tolerances impact the performance of Nipoflanges?
Dimension tolerances ensure proper fit and prevent stress concentration, leakage, or misalignment:
- O.D. & Hub Diameter: Must stay within ± tolerance to match the run pipe and flange mating surface.
- Length thru Hub: Critical for welding integrity and stress distribution.
- Bolt Circle & Hole Spacing: Precise spacing prevents flange misalignment and ensures proper gasket compression.
- Contact Face Diameter: Raised Face, Tongue & Groove, or Male-Female faces must meet tolerances for leak-free bolted connections.