ANSI B16.5 Dimensions & Ratings
ASME B16.5 Standard Flanges: Dimensions | Specifications | Material Grade | Standards | About ANSI B16.5 | All Product Types
ASME B16.5 is the globally recognized standard for pipe flanges and flanged fittings covering sizes from ½″ to 24″ nominal bore and pressure classes ranging from 150 to 2500. This specification defines essential parameters such as flange dimensions, facing types, bolt hole configurations, pressure-temperature ratings, tolerance limits, and testing requirements. It is applicable to forged flanges made from carbon steel, stainless steel, alloy steel, and high-performance alloys.
At Nutech, we manufacture and export forged steel flanges that fully comply with ASME B16.5, offering superior precision, strength, and dimensional accuracy. Our flanges are available in various types including Weld Neck (WNRF), Slip-On (SORF), Socket Weld (SWRF), Threaded, Blind (BLRF), Lap Joint, and Ring Type Joint (RTJ) — with face types such as Raised Face (RF), Flat Face (FF), and RTJ, depending on pressure class and sealing requirements.
The B16.5 standard also governs flange thickness, bolt circle diameter, bolt hole size, and gasket compatibility — making it critical for high-pressure systems in refineries, petrochemical plants, offshore installations, and power generation facilities. We ensure strict adherence to machining tolerances, pressure-temperature charts, and dimensional accuracy by conducting comprehensive in-house testing and certification in line with EN 10204 3.1 / 3.2.
Backed by global export experience, our ASME B16.5 flanges are manufactured for projects requiring uncompromising quality and full traceability, with all products supplied with markings as per B16.5 specifications, including material grade, pressure class, heat number, and size.
For complete technical details, including dimensions, pressure rating classes, weight charts, sizes, tolerances, and material specifications of our ANSI B16.5 Standard Flanges, please download the full Catalog PDF below.
Specification | Details |
---|---|
Design Standard | ASME B16.5 / ANSI B16.5 |
Flange Types | Weld Neck (WNRF), Blind (BLRF), Slip-On (SORF), Socket Weld (SWRF), Threaded (TH), Lap Joint, Ring Type Joint (RTJ), and More |
Size Range | ½″ NB to 24″ NB (DN15 to DN600) |
Pressure Ratings | Class 150, 300, 600, 900, 1500, 2500 (PN20 to PN420) |
Face Types | Raised Face (RF), Flat Face (FF), Ring Type Joint (RTJ) |
Drilling Template | As per ASME B16.5 bolt circle diameter & bolt hole arrangement |
Flange Thickness | As per class and size, including tolerance as per ASME B16.5 |
Dimensional Tolerances | Within ASME B16.5 tolerance limits for OD, thickness, bolt holes, and facing |
Surface Finish | Stock finish, serrated finish (spiral or concentric), smooth finish as per RF/RTJ specs |
Marking | Heat Number, Material Grade, Pressure Class, Size, Standard (B16.5) |
Testing | Dimensional, Hydrostatic (on request), PMI, Visual, and Surface Inspection |
Documentation | EN 10204 3.1 / 3.2 certificates, compliance with NACE MR0175, ISO 15156 (as applicable) |
Application Industries | Oil & Gas, Petrochemical, Power Generation, Water Treatment, Food & Beverage, Fire Protection Systems, Pulp & Paper, Shipbuilding, HVAC, Offshore |
Origin | Made in India (by Nutech Overseas) |
Export Network | USA, Europe, and Middle East |
Material Category | B16.5 Flange Grades |
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Stainless Steel B16.5 Flange | ASTM A182 F304 / F304L / F304H, F316 / F316L / F316Ti, F310, F309S, F317 / F317L, F321 / F321H, F347 / F347H, F904L, ASTM A351 CF3 / CF3M / CF8 / CF8M / CF8C, DIN 1.4301, 1.4306, 1.4307, 1.4311, 1.4401, 1.4404, 1.4408, 1.4409, 1.4541, 1.4571, 1.4550, 1.4435, 1.4539 |
Duplex Steel B16.5 Flange | ASTM A182 F51 / F52 / F53 / F54 / F55 / F57 / F59 / F60 / F61, UNS S31803 / S32205 |
Super Duplex Steel B16.5 Flange | ASTM A182 F53 / F55 / F57 / F59 / F60 / F61, UNS S32750 / S32760 |
Carbon Steel B16.5 Flange | ASTM A105 / A105N, ASTM A350 LF2, ASTM A694 F52 / F56 / F60 / F65 / F70 / F80, ASTM A216 WCB, DIN 1.0460 / 1.0402 / 1.0619, Die Steel, Mild Steel |
Alloy Steel B16.5 Flange | ASTM A182 F5 / F9 / F11 / F12 / F22 / F91, AISI 4130 / 4140 |
Nickel Alloy B16.5 Flange | Nickel 200 / 201, ASTM B564 |
Monel B16.5 Flange | Monel 400 (UNS N04400), Monel K500 (UNS N05500), ASTM B564 |
Inconel B16.5 Flange | Inconel 600 / 601 / 625 / 690 / 718 / 783 / X750, ASTM B564 |
Incoloy B16.5 Flange | Incoloy 800 / 800H / 800HT (UNS N08800), Incoloy 825 (UNS N08825), Incoloy 925, ASTM B564 |
Hastelloy B16.5 Flange | Hastelloy C276 (UNS N10276), C22 (UNS N06022), C4, C2000, B2, B3, X, ASTM B564 |
Alloy 20 B16.5 Flange | Alloy 20 / 20Cb-3, Carpenter® 20, ASTM B462 |
254 SMO B16.5 Flange | SMO 254 / 6Mo, UNS S31254, DIN 1.4547, ASTM A182 |
Copper Nickel B16.5 Flange | Copper Nickel 90/10 (C70600), 70/30 (C71500), UNS C71640, ASTM B61 / B62 / B151 / B152 |
Copper B16.5 Flange | TP1, TP2, T1, T2, C10100–C12300, C14200–C17200, C21000–C71520, including C10930, C11000, C11400, C12000, C12200, C26000, C28000, C33000, C44300, C70600, etc. |
Brass B16.5 Flange | Grades 3602, 2604, H59, H62, etc. |
Aluminium B16.5 Flange | Aluminium Grades 5052, 6061, 6063, 2017, 7075, etc. |
Titanium B16.5 Flange | ASTM B381 Gr.1 / Gr.2 / Gr.4 / Gr.5 / Gr.7, UNS R50250 / R50400 / R50550 / R50700 / R52400 / R53400 / R56320 / R56400 |
Other Special Grades | Al6XN, Tin Bronze, Aluminium Bronze, Lead Bronze, Nimonic 75 / 80A / 90 |
ASME B16.5 is a globally recognized standard that defines the dimensions, tolerances, pressure-temperature ratings, face types, and materials for pipe flanges and flanged fittings ranging from ½″ to 24″ nominal size (DN15–DN600). It is critical in flange selection because:
Using flanges that meet ASME B16.5 guarantees system integrity, global compliance, and safety in pressurized piping environments.
ASME B16.5 flanges are available in the following standard pressure classes:
These classes define the maximum allowable pressure the flange can withstand at various temperatures. Selection depends on design pressure, temperature, and material. For example, a Class 600 flange made of carbon steel may have a different pressure-temperature rating compared to one made from stainless steel. Always refer to ASME B16.5 pressure-temperature charts for accurate selection.
Tolerances specified in ASME B16.5—even for outer diameter, flange thickness, bolt-hole spacing, and face flatness—aren’t just arbitrary limits; they ensure interchangeability, proper alignment, and seal integrity across piping components.
Why Tolerances Matter:
Ensures exact bolt-hole alignment during assembly, preventing stresses or flange distortion during bolt-up. For flanges under 24″ OD, tolerances may be ±1/16″ (≈1.6 mm), ensuring smooth fitting
Prevents under-thickness or excessive machining—critical for pressure containment. Thicker flanges risk extra material cost; thinner ones risk strength loss .
Proper finish (e.g., spiral-serrated or concentric-smooth) and flatness prevent uneven gasket compression, avoiding leakage or blowout—especially in high-pressure applications
ASME intentionally defines tolerances based on the least accurate yet practical manufacturing methods. Tighter dims don’t yield better seal—in fact, they increase cost and complexity without adding safety
Selecting the correct ASME B16.5 flange involves evaluating several key factors to ensure compatibility, safety, and efficiency in your piping system:
Key Selection Criteria:
Always refer to engineering design data and project specifications to make an informed flange selection that ensures long-term performance and compliance.
While both ASME B16.5 and ASME B16.47 cover flanged components, they differ mainly in terms of size range, application scope, and dimensional standards:
Feature | ASME B16.5 | ASME B16.47 |
---|---|---|
Size Range | ½″ to 24″ (DN15 to DN600) | 26″ to 60″ (DN650 to DN1500) |
Application | Standard industrial and process piping | Large-diameter pipelines (e.g., storage tanks, water lines) |
Flange Series | Not applicable | Series A (from MSS SP-44), Series B (from API 605) |
Bolt Circle Diameter | Standard bolt pattern | Series A: heavier, wider BCD; Series B: lighter flange design |
Pressure Ratings | Class 150 to 2500 | Class 75 to 900 (varies by series) |
Common Flange Types | Weld Neck, Slip-On, Blind, Socket Weld, Threaded | Weld Neck and Blind flanges |
Industry Use | Oil & Gas, Petrochemical, Chemical, Power, Water | Heavy industrial, large-scale piping systems |
ASME B16.5 is used for standard-sized piping, while ASME B16.47 is specialized for large diameter flanges often used in heavy industrial installations.
The pressure-temperature (P–T) ratings in ASME B16.5 are critical because they define how much pressure a flange can safely withstand at a given temperature. These ratings vary based on:
Key Factors:
For example:
Always refer to the ASME P–T chart during design to ensure the selected flange meets both operational and safety requirements.
Nutech Overseas is a trusted manufacturer and global exporter of ASME B16.5 flanges, serving industries across multiple continents. We supply flanges to EPC contractors, oil & gas firms, and industrial users in:
We provide custom markings, export-grade packaging, and complete documentation in compliance with international shipping and inspection standards.