Discover the essential dimensions for Flanges in this comprehensive guide. We cover everything you need to know about various Flange Types, including their sizes, shapes, and specifications, ensuring that your projects adhere to industry standards. Whether you’re working with standard or custom flange, this resource provides accurate and reliable measurements for all your flange needs. Our guide will help you choose the right flanges to fit your piping systems and ensure optimal performance in your applications.
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