Pipe Flanges: Ensuring Secure and Leak-Proof Joints
Pipe flanges are indispensable components in industrial piping systems, facilitating secure connections between pipes, valves, fittings, and more. At Fortune Fittings Pvt. Ltd., we offer a wide range of pipe flanges designed to meet diverse industrial needs with precision engineering and top-quality materials. In this article, we delve into the intricacies of pipe flanges, their types, working principles, materials, and applications.
How Pipe Flanges Work
Pipe flanges work by bolting together piping components with the aid of a gasket to ensure a leak-free connection. The components of a typical pipe flange connection include the pipe itself, the flange, a gasket for sealing, bolting, and in some cases, welding.
Standard Types of Pipe Flanges
Threaded Flange
- Joined using male and female threads.
- Suitable for low-pressure applications like water and compressed air systems.
Welding Neck Flange
- Welded to the pipe for high-pressure applications.
- Offers unrestricted flow without turbulence or erosion.
Slip-On Flange
- Secured with fillet welds on the inside and outside.
- Ideal for low-pressure, non-critical applications.
Socket Weld Flange
- Used for small-size, high-pressure pipes.
- Pipe is inserted into the flange socket and welded in place.
Lap Joint Flange
- Combined with stub ends to reduce costs.
- Ideal for connecting dissimilar materials in pipeline systems.
Blind Flange
- Seals or closes pipelines to block fluid flow.
- Allows easy access for maintenance activities.
Precision Engineering by Fortune Fittings Pvt. Ltd.
Fortune Fittings Pvt. Ltd. is a renowned manufacturer of Pipe Flanges, backed by years of industry experience and a commitment to excellence. Our state-of-the-art manufacturing processes and advanced equipment enable us to produce flanges that meet the most demanding specifications. We prioritize quality and reliability in every product we deliver, ensuring that our Pipe Flanges exceed customer expectations.
Pipe Flange Face Variants
Pipe flanges come in various face variants, each with its unique sealing characteristics:
Common Pipe Flange Materials
At Fortune Fittings Pvt. Ltd., we offer pipe flanges in a variety of materials, including:
- Carbon Steel
- Alloy Steel
- Duplex Steel
- Stainless Steel
- Nickel Alloys (Inconel, Incoloy, Hastelloy, Monel)
Pipe Flange Classification and Pressure Rating
Pipe flanges are classified based on pressure ratings, ranging from 150 to 2500 according to ANSI/ASME B16.5 standards. The pressure rating determines the maximum allowable pressure a flange can withstand at varying temperatures, making it crucial to select the right flange for your application’s requirements.
Why Choose Fortune Fittings Pvt. Ltd.?
- High-Quality Manufacturing: We use advanced technology and techniques to produce durable and reliable flanges.
- Extensive Experience: Our team of professionals provides expert technical support and excellent customer service.
- Wide Range of Products: We offer a variety of sizes, materials, and pressure ratings to meet the diverse needs of our clients.
Conclusion
For premium-quality Pipe Flanges tailored to your specific requirements, partner with Fortune Fittings Pvt. Ltd. Our dedication to craftsmanship, reliability, and customer satisfaction ensures that you receive optimal solutions for your industrial piping needs. Contact us today to explore our product range and request a competitive price list.
Flanges Dimensions
Dimensions Weld Neck Flanges & Stud Bolts
ASME B16.5
OTHER DIA | NPS 1/2 – O.D. 21.3 | |||||
CLass | 150 | 300 | 600 | 900 | 1500 | 2500 |
DIA A | 30 | 38 | 38 | 38 | 38 | 43 |
DIA D | 90 | 95 | 95 | 120 | 120 | 135 |
THK B | 11.2 | 14.3 | 20.7 | 28.7 | 28.7 | 36.6 |
DIA G | 35.1 | 35.1 | 35.1 | 35.1 | 35.1 | 35.1 |
DIA K | 60.3 | 66.7 | 66.7 | 82.6 | 82.6 | 88.9 |
H | 47.6 | 52.6 | 58.4 | 66.4 | 66.4 | 79.4 |
NO. L | 4 | 4 | 4 | 4 | 4 | 4 |
DIA L | 15.9 | 15.9 | 15.9 | 22.2 | 22.2 | 22.2 |
Stud Bolts Diameter x Length | ||||||
DIA (in) | 1/2 | 1/2 | 1/2 | 3/4 | 3/4 | 3/4 |
lgth (mm) | 55 | 65 | 75 | 110 | 110 | 120 |
- IMPORTANT! please read this short article
Dimensional Tolerances of Weld Neck Flanges ASME B16.5

Dimensions Slip On Flanges & Stud Bolts
ASME B16.5
OTHER DIA | NPS 1/2 ID 22.3 | |||||
CLass | 150 | 300 | 600 | 900 | 1500 | 2500 |
DIA A | 30 | 38 | 38 | 38 | 38 | … |
DIA D | 90 | 95 | 95 | 120 | 120 | … |
THK B | 11.2 | 14.3 | 20.7 | 28.7 | 28.7 | … |
DIA G | 35.1 | 35.1 | 35.1 | 35.1 | 35.1 | … |
DIA K | 60.3 | 66.7 | 66.7 | 82.6 | 82.6 | … |
H | 15.6 | 22.6 | 28.4 | 38.4 | 38.4 | … |
NO. L | 4 | 4 | 4 | 4 | 4 | … |
DIA L | 15.9 | 15.9 | 15.9 | 22.2 | 22.2 | … |
Stud Bolts Diameter x Length | ||||||
DIA (in) | 1/2 | 1/2 | 1/2 | 3/4 | 3/4 | … |
lgth (mm) | 55 | 65 | 75 | 110 | 110 | … |
- IMPORTANT! please read this short article
Dimensional Tolerances of Weld Neck Flanges ASME B16.5
Outside Diameter * Tolerances not listed in ASME B16.5 2013≤24 = 1.6 mm (0.06 in)>24 = ±3.2 mm (±0.12 in) Inside Diameter ≤ 10 = ± 0.8 mm≥ 12 = + 1.6 mm / – 0 mm Outside Diameter of Hub ≤ 12 = + 2.4 mm / – 1.6 mm≥ 14 = ± 3.2 mm Diameter of Counterbore Same as for Inside Diameter Drilling Bolt Circle = 1.6 mmBolt Hole Spacing = ± 0.8 mm Eccentricity of Bolt Circle ≤ 2.1/2 = 0.8 mm max.≥ 3 = 1.6 mm max. Thickness ≤ 18 = + 3.2 mm / – 0≥ 20 = + 4.8 mm / – 0 Length thru Hub ≤ 18 = + 3.2 mm / – 0.8 mm≥ 20 = + 4.8 mm / – 1.6 mm Diameter of Contact Face 1.6 mm Raised Face = ± 0.8 mm6.35 mm Raised FaceTongue and Groove / Male-Female± 0.4 mmDimensions Socket Weld Flanges & Stud Bolts
ASME B16.5
OTHER DIA | NPS 1/2 ID=22.3 F=9.5 | |||||
CLass | 150 | 300 | 600 | 900 | 1500 | 2500 |
DIA A | 30 | 38 | 38 | … | 38 | … |
DIA D | 90 | 95 | 95 | … | 120 | … |
THK B | 11.2 | 14.3 | 20.7 | … | 28.7 | … |
DIA G | 35.1 | 35.1 | 35.1 | … | 35.1 | … |
DIA K | 60.3 | 66.7 | 66.7 | … | 82.6 | … |
H | 15.6 | 22.6 | 28.4 | … | 38.4 | … |
NO. L | 4 | 4 | 4 | … | 4 | … |
DIA L | 15.9 | 15.9 | 15.9 | … | 22.2 | … |
Stud Bolts Diameter x Length | ||||||
DIA (in) | 1/2 | 1/2 | 1/2 | … | 3/4 | … |
lgth (mm) | 55 | 65 | 75 | … | 110 | … |
- ID 2 = Depending on the wall thickness of the pipe, must bespecified by the purchaser.
- IMPORTANT! please read this short article
Dimensional Tolerances of Socket Weld Flanges ASME B16.5
Outside Diameter * Tolerances not listed in ASME B16.5 2013≤ 24 = 1.6 mm> 24 = ± 3.2 mm Inside Diameter ≤ 10 = ± 0.8 mm≥ 12 = + 1.6 mm / – 0 mm Outside Diameter of Hub ≤ 12 = + 2.4 mm / – 1.6 mm≥ 14 = ± 3.2 mm Diameter of Counterbore Same as for Inside Diameter Drilling Bolt Circle = 1.6 mmBolt Hole Spacing = ± 0.8 mm Eccentricity of Bolt Circle ≤ 2.1/2 = 0.8 mm max.≥ 3 = 1.6 mm max. Thickness ≤ 18 = + 3.2 mm / – 0≥ 20 = + 4.8 mm / – 0 Length thru Hub ≤ 18 = + 3.2 mm / – 0.8 mm≥ 20 = + 4.8 mm / – 1.6 mm Diameter of Contact Face 1.6 mm Raised Face = ± 0.8 mm6.35 mm Raised FaceTongue and Groove / Male-Female± 0.4 mm Studs are measured parallel to the axis (L) from the first to the threadwithout the chamfers (points). S = free threads equals 1/3 time bolt dia Hex bolts are measured from under the head to the top of de boltDimensions Lap Joint Flanges & Stud Bolts
ASME B16.5
OTHER DIA | NPS 1/2 ID=22.9 r=3 | |||||
CLass | 150 | 300 | 600 | 900 | 1500 | 2500 |
DIA A | 30 | 38 | 38 | 38 | 38 | 43 |
DIA D | 90 | 95 | 95 | 120 | 120 | 135 |
THK B | 11.2 | 14.3 | 14.3 | 22.3 | 22.3 | 30.2 |
DIA K | 60.3 | 66.7 | 66.7 | 82.6 | 82.6 | 88.9 |
H | 16 | 22 | 22 | 32 | 32 | 40 |
NO. L | 4 | 4 | 4 | 4 | 4 | 4 |
DIA L | 15.9 | 15.9 | 15.9 | 22.2 | 22.2 | 22.2 |
Stud Bolts Diameter x Length | ||||||
DIA (in) | 1/2 | 1/2 | 1/2 | 3/4 | 3/4 | 3/4 |
lgth (mm) | 55 | 65 | 75 | 110 | 110 | 120 |
- IMPORTANT! please read this short article
Dimensional Tolerances of Lap Joint Flanges ASME B16.5
Outside Diameter * Tolerances not listed in ASME B16.5 2013≤ 24 = 1.6 mm> 24 = ± 3.2 mm Inside Diameter ≤ 10 = ± 0.8 mm≥ 12 = + 1.6 mm / – 0 mm Outside Diameter of Hub ≤ 12 = + 2.4 mm / – 1.6 mm≥ 14 = ± 3.2 mm Diameter of Counterbore Same as for Inside Diameter Drilling Bolt Circle = 1.6 mmBolt Hole Spacing = ± 0.8 mm Eccentricity of Bolt Circle ≤ 2.1/2 = 0.8 mm max.≥ 3 = 1.6 mm max. Thickness ≤ 18 = + 3.2 mm / – 0≥ 20 = + 4.8 mm / – 0 Length thru Hub ≤ 18 = + 3.2 mm / – 0.8 mm≥ 20 = + 4.8 mm / – 1.6 mm Diameter of Contact Face 1.6 mm Raised Face = ± 0.8 mm6.35 mm Raised FaceTongue and Groove / Male-Female± 0.4 mm Studs are measured parallel to the axis (L) from the first to the threadwithout the chamfers (points). S = free threads equals 1/3 time bolt dia Hex bolts are measured from under the head to the top of de boltDimensions Threaded Flanges & Stud Bolts
ASME B16.5
OTHER DIA | NPS 1/2 | |||||
CLass | 150 | 300 | 600 | 900 | 1500 | 2500 |
DIA A | 30 | 38 | 38 | 38 | 38 | 43 |
DIA D | 90 | 95 | 95 | 120 | 120 | 135 |
THK B | 11.2 | 14.3 | 20.7 | 28.7 | 28.7 | 36.6 |
DIA G | 35.1 | 35.1 | 35.1 | 35.1 | 35.1 | 35.1 |
DIA K | 60.3 | 66.7 | 66.7 | 82.6 | 82.6 | 88.9 |
H | 15.6 | 22.6 | 28.4 | 38.4 | 38.4 | 46.4 |
NO. L | 4 | 4 | 4 | 4 | 4 | 4 |
DIA L | 15.9 | 15.9 | 15.9 | 22.2 | 22.2 | 22.2 |
Stud Bolts Diameter x Length | ||||||
DIA (in) | 1/2 | 1/2 | 1/2 | 3/4 | 3/4 | 3/4 |
lgth (mm) | 55 | 65 | 75 | 110 | 110 | 120 |
- IMPORTANT! please read this short article
Dimensional Tolerances of Threaded Flanges ASME B16.5
Outside Diameter * Tolerances not listed in ASME B16.5 2013≤ 24 = 1.6 mm> 24 = ± 3.2 mm Inside Diameter Within Limits on Boring Gauge Drilling Bolt Circle = 1.6 mmBolt Hole Spacing = ± 0.8 mm Eccentricity of Bolt Circle ≤ 2.1/2 = 0.8 mm max.≥ 3 = 1.6 mm max. Outside Diameter of Hub ≤ 12 = + 2.4 mm / – 1.6 mm≥ 14 = ± 3.2 mm Diameter of Counterbore Same as forInside Diameter Thickness ≤ 18 = + 3.2 mm / – 0≥ 20 = + 4.8 mm / – 0 Length thru Hub ≤ 18 = + 3.2 mm / – 0.8 mm≥ 20 = + 4.8 mm / – 1.6 mm Diameter of Contact Face 1.6 mm Raised Face = ± 0.8 mm6.35 mm Raised FaceTongue and Groove / Male-Female± 0.4 mm Studs are measured parallel to the axis (L) from the first to the threadwithout the chamfers (points). S = free threads equals 1/3 time bolt dia Hex bolts are measured from under the head to the top of de boltDimensions Blind Flanges & Stud Bolts
ASME B16.5
OTHER DIA | NPS 1/2 | |||||
CLass | 150 | 300 | 600 | 900 | 1500 | 2500 |
DIA D | 90 | 95 | 95 | 120 | 120 | 135 |
B | 11.2 | 14.3 | 20.7 | 28.7 | 28.7 | 36.6 |
DIA G | 35.1 | 35.1 | 35.1 | 35.1 | 35.1 | 35.1 |
DIA K | 60.3 | 66.7 | 66.7 | 82.6 | 82.6 | 88.9 |
NO. L | 4 | 4 | 4 | 4 | 4 | 4 |
DIA L | 15.9 | 15.9 | 15.9 | 22.2 | 22.2 | 22.2 |
Stud Bolts Diameter x Length | ||||||
DIA (in) | 1/2 | 1/2 | 1/2 | 3/4 | 3/4 | 3/4 |
lgth (mm) | 55 | 65 | 75 | 110 | 110 | 120 |
- IMPORTANT! please read this short article
Dimensional Tolerances of Blind Flanges ASME B16.5
Outside Diameter * Tolerances not listed in ASME B16.5 2013≤ 24 = 1.6 mm> 24 = ± 3.2 mm Inside Diameter not applicable Outside Diameter of Hub ≤ 12 = + 2.4 mm / – 1.6 mm≥ 14 = ± 3.2 mm Outside Diameter of Hub ≤ 12 = + 2.4 mm / – 1.6 mm≥ 14 = ± 3.2 mm Drilling Bolt Circle = 1.6 mmBolt Hole Spacing = ± 0.8 mm Eccentricity of Bolt Circle ≤ 2.1/2 = 0.8 mm max.≥ 3 = 1.6 mm max. Thickness ≤ 18 = + 3.2 mm / – 0≥ 20 = + 4.8 mm / – 0 Length thru Hub ≤ 18 = + 3.2 mm / – 0.8 mm≥ 20 = + 4.8 mm / – 1.6 mm Diameter of Contact Face 1.6 mm Raised Face = ± 0.8 mm6.35 mm Raised FaceTongue and Groove / Male-Female ± 0.4 mm Studs are measured parallel to the axis (L) from the first to the threadwithout the chamfers (points). S = free threads equals 1/3 time bolt dia Hex bolts are measured from under the head to the top of de bolt