Weld neck flange dimensions are covered in ASME B16.5 – which covers Pipe Flanges and Flanged Fittings for size NPS ½” to 24” for above NPS 26” to 60” it should be as per ASME B16.47.

During a dimensional inspection of weld neck flange, you should check for

  • Outer & Inner Diameter of body
  • Bolt Circle & Bolt hole Diameter
  • the thickness of weld end
  • Length of the Hub and
  • Straightness and alignment of the bolt hole
weld neck flange dimensions

Class 150 Weld Neck Flange Dimensions

Size in InchSize in mmOuter DiameterFlange ThicknessHub ODWeld Neck ODWelding Neck LengthBoreRF DiameterRF HeightPCDWeld Face
ABCDEFGHIJ
1/215909.63021.346Welding Neck bore is derived from the pipe schedule34.9260.31.6
3/42010011.23826.75142.9269.91.6
12511012.74933.45450.8279.41.6
1 1/43211514.35942.25663.5288.91.6
1 1/24012515.96548.36073298.41.6
25015017.57860.36292.12120.71.6
2 1/26518020.7907368104.82139.71.6
38019022.310888.9681272152.41.6
3 1/29021522.3122101.670139.72177.81.6
410023022.3135114.375157.22190.51.6
512525522.3164141.387185.72215.91.6
615028023.9192168.387215.92241.31.6
820034527246219.1100269.92298.51.6
1025040528.6305273100323.823621.6
1230048530.2365323.81133812431.81.6
1435053533.4400355.6125412.82476.31.6
1640059535457406.4125469.92539.81.6
1845063538.1505457.2138533.42577.91.6
2050070041.3559508143584.226351.6
2460081546.1663610151692.22749.31.6

Class 150 Weld Neck Flange Stud & Bolt Dimensions

Size in InchSize in mmNo of BoltsBolt Size UNCMachine Bolt LengthRF Stud LengthHole SizeISO Stud SizeWeight in kg
1/21541/250555/8M140.6
3/42041/250655/8M140.9
12541/255655/8M141.4
1 1/43241/255705/8M141.4
1 1/24041/265705/8M141.8
25045/870853/4M162.7
2 1/26545/875903/4M163.7
38045/875903/4M164.6
3 1/29085/875903/4M165.5
410085/875903/4M166.8
512583/485957/8M208.7
615083/4851007/8M2010.9
820083/4901107/8M2017.7
10250127/81001151M2424
12300127/81001201M2437
143501211151351 1/8M2750
164001611151351 1/8M2764
18450161 1/81251451 1/4M3068
20500201 1/81401601 1/4M3082
24600201 1/41501701 3/8M33118
Piping Courses

Class 300 Weld Neck Flange Dimensions

Size in InchSize in mmOuter DiameterFlange ThicknessHub ODWeld Neck ODWelding Neck LengthBoreRF DiameterRF HeightPCDWeld Face
ABCDEFGHIJ
1/2159512.73821.351Welding Neck bore is derived from the pipe schedule34.9266.71.6
3/42011514.34826.75642.9282.61.6
12512515.95433.46050.8288.91.6
1 1/43213517.56442.26463.5298.41.6
1 1/24015519.17048.367732114.31.6
25016520.78460.36892.121271.6
2 1/26519023.91007375104.82149.21.6
3802102711788.9781272168.31.6
3 1/29023028.6133101.679139.72184.21.6
410025530.2146114.384157.222001.6
512528033.4178141.397185.722351.6
615032035206168.397215.92269.91.6
820038039.7260219.1110269.92330.21.6
1025044546.1321273116323.82387.41.6
1230052049.3375323.81293812450.81.6
1435058552.4425355.6141412.82514.41.6
1640065055.6483406.4144469.92571.51.6
1845071058.8533457157533.42628.61.6
2050077562587508160584.22685.81.6
2460091568.3702610167692.22812.81.6

Class 300 Weld Neck Flange Stud & Bolt Dimensions

Size in InchSize in mmNo of BoltsBolt Size UNCMachine Bolt LengthRF Stud LengthHole SizeISO Stud SizeWeight in kg
1/21541/255655/8M141.4
3/42045/865753/4M161.4
12545/865753/4M161.8
1 1/43245/870853/4M162.3
1 1/24043/475907/8M203.2
25085/875903/4M164.1
2 1/26583/4851007/8M205.5
38083/4901107/8M206.8
3 1/29083/4951107/8M208.2
410083/4951157/8M2011.4
512583/41101207/8M2014.6
6150123/41101207/8M2019.1
8200127/81201401M2431
102501611401601 1/8M2742
12300161 1/81451701 1/4M3064
14350201 1/81601801 1/4M3082
16400201 1/41651901 3/8M33113
18450241 1/41701951 3/8M33145
20500241 1/41852051 3/8M33182
24600241 1/22052301 5/8M39264

Class 400 Weld Neck Flange Dimensions

Size in InchSize in mmOuter DiameterFlange ThicknessHub ODWeld Neck ODWelding Neck LengthBoreRF DiameterRF HeightPCDWeld Face
ABCDEFGHIJ
1/2159514.33821.352Welding Neck bore is derived from the pipe schedule34.9766.71.6
3/42011515.94826.75742.9782.61.6
12512517.55433.46250.8788.91.6
1 1/43213520.76442.26763.5798.41.6
1 1/24015522.37048.370737114.31.6
25016525.48460.37392.171271.6
2 1/26519028.61007379104.87149.21.6
38021031.811788.9831277168.31.6
3 1/29023035133101.686139.77184.21.6
410025535146114.389157.272001.6
512528038.1178141.3102185.772351.6
615032041.3206168.3103215.97269.91.6
820038047.7260219.1117269.973301.6
1025044554321273124323.87387.41.6
1230052057.2375323.81373817450.81.6
1435058560.4425355.6149412.87514.41.6
1640065063.5483406.4152469.97571.51.6
1845071066.7533457165533.47628.61.6
2050077569.9587508168584.27685.81.6
2460091576.2702610175692.27812.81.6

Class 400 Weld Neck Flange Stud & Bolt Dimensions

Size in InchSize in mmNo of BoltsBolt Size UNCRF Stud LengthHole SizeISO Stud Size
1/21541/2755/8M14
3/42045/8903/4M16
12545/8903/4M16
1 1/43245/8953/4M16
1 1/24043/41107/8M20
25085/81103/4M16
2 1/26583/41207/8M20
38083/41257/8M20
3 1/29087/81401M24
410087/81401M24
512587/81451M24
6150127/81501M24
82001211701 1/8M27
10250161 1/81901 1/4M30
12300161 1/42051 3/8M33
14350201 1/42101 3/8M33
16400201 3/82201 1/2M36
18450241 3/82301 1/2M36
20500241 1/22401 3/4M39
24600241 3/42651 7/8M45
How to Read PID Course

Class 600 Weld Neck Flange Dimensions

Size in InchSize in mmOuter DiameterFlange ThicknessHub ODWeld Neck ODWelding Neck LengthBoreRF DiameterRF HeightPCDWeld Face
ABCDEFGHIJ
1/2159514.33821.352Welding Neck bore is derived from the pipe schedule34.9766.71.6
3/42011515.94826.75742.9782.61.6
12512517.55433.46250.8788.91.6
1 1/43213520.76442.26763.5798.41.6
1 1/24015522.37048.370737114.31.6
25016525.48460.37392.171271.6
2 1/26519028.61007379104.87149.21.6
38021031.811788.9831277168.31.6
3 1/29023035133101.686139.77184.21.6
410027538.1152114.3102157.27215.91.6
512533044.5189141.3114185.77266.71.6
615035547.7222168.3117215.97292.11.6
820042055.6273219.1133269.97349.21.6
1025051063.5343273152323.87431.81.6
1230056066.7400323.815638174891.6
1435060569.9432355.6165412.875271.6
1640068576.2495406.4178469.97603.21.6
1845074582.6546457184533.476541.6
2050081588.9610508190584.27723.91.6
24600940101.6718610203692.27838.21.6

Class 600 Weld Neck Flange Stud & Bolt Dimensions

Size in InchSize in mmNo of BoltsBolt Size UNCRF Stud LengthHole SizeISO Stud SizeWeight in kg
1/21541/2755/8M141.5
3/42045/8903/4M161.8
12545/8903/4M161.8
1 1/43245/8953/4M162.7
1 1/24043/41107/8M203.7
25085/81103/4M165.5
2 1/26583/41207/8M208.2
38083/41257/8M2010.5
3 1/29087/81401M2411.8
410087/81451M2419.1
5125811651 1/8M2731
61501211701 1/8M2736
8200121 1/81901 1/4M3055
10250161 1/42151 3/8M3386
12300201 1/42201 3/8M33102
14350201 3/82351 1/2M36127
16400201 1/22551 5/8M39177
18450201 5/82751 3/4M42216
20500241 5/82851 3/4M42268
24600241 7/83302M48377

Class 900 Weld Neck Flange Dimensions

Size in InchSize in mmOuter DiameterFlange ThicknessHub ODWeld Neck ODWelding Neck LengthBoreRF DiameterRF HeightPCDWeld Face
ABCDEFGHIJ
1/21512022.33821.360Welding Neck bore is derived from the pipe schedule34.9782.61.6
3/42013025.44426.77042.9788.91.6
12515028.65233.47350.87101.61.6
1 1/43216028.66442.27363.57111.11.6
1 1/24018031.87048.383737123.81.6
25021538.110560.310292.17165.11.6
2 1/26524541.312473105104.87190.51.6
38024038.112788.91021277190.51.6
410029044.5159114.3114157.272351.6
512535050.8190141.3127185.77279.41.6
615038055.6235168.3140215.97317.51.6
820047063.5298219.1162269.97393.71.6
1025054569.9368273184323.87469.91.6
1230061079.4419323.82003817533.41.6
1435064085.8451355.6213412.87558.81.6
1640070588.9508406.4216469.976161.6
18450785101.6565457229533.47685.81.6
20500855108622508248584.27749.31.6
246001040139.7749610292692.27901.71.6

Class 900 Weld Neck Flange Stud & Bolt Dimensions

Size in InchSize in mmNo of BoltsBolt Size UNCRF Stud LengthHole SizeISO Stud SizeWeight in kg
1/21543/41107/8M202.3
3/42043/41157/8M202.7
12547/81251M244.1
1 1/43247/81251M244.6
1 1/240411401 1/8M275.9
25087/81451M2411.5
2 1/265811601 1/8M2716.5
38087/81451M2414
410081 1/81701 1/4M3023
512581 1/41901 3/8M3339.5
6150121 1/81901 1/4M3050
8200121 3/82201 1/2M3680
10250161 3/82351 1/2M36118
12300201 3/82551 1/2M36148
14350201 1/22751 5/8M39182
16400201 5/82851 3/4M42225
18450201 7/83252M48300
205002023502 1/8M52373
24600202 1/24402 5/8M64680

Class 1500 Weld Neck Flange Dimensions

Size in InchSize in mmOuter DiameterFlange ThicknessHub ODWeld Neck ODWelding Neck LengthBoreRF DiameterRF HeightPCDWeld Face
ABCDEFGHIJ
1/21512022.33821.360Welding Neck bore is derived from the pipe schedule34.9782.61.6
3/42013025.44426.77042.9788.91.6
12515028.65233.47350.87101.61.6
1 1/43216028.66442.27363.57111.11.6
1 1/24018031.87048.383737123.81.6
25021538.110560.310292.17165.11.6
2 1/26524541.312473105104.87190.51.6
38026547.713388.91171277203.21.6
410031054162114.3124157.27241.31.6
512537573.1197141.3156185.77292.11.6
615039582.6229168.3171215.97317.51.6
820048592.1292219.1213269.97393.71.6
10250585108368273254323.87482.61.6
12300675123.9451323.82833817571.51.6
14350750133.4495355.6298412.876351.6
16400825146.1552406.4311469.97704.81.6
18450915162597457327533.47774.71.6
20500985177.8641508356584.27831.81.6
246001170203.2762610406692.27990.61.6

Class 1500 Weld Neck Flange Stud & Bolt Dimensions

Size in InchSize in mmNo of BoltsBolt Size UNCRF Stud LengthHole SizeISO Stud SizeWeight in kg
1/21543/41107/8M202.3
3/42043/41157/8M202.7
12547/81251M244.1
1 1/43247/81251M244.6
1 1/240411401 1/8M275.9
25087/81451M2411.4
2 1/265811601 1/8M2716.4
38081 1/81801 1/4M3021.8
410081 1/41951 3/8M3333
512581 1/22501 5/8M3959
6150121 3/82601 1/2M3675
8200121 5/82901 3/4M42125
10250121 7/83352M48207
123001623752 1/8M52314
14350162 1/44052 3/8M56427
16400162 1/24452 5/8M64568
18450162 3/44952 7/8M72738
205001635403 1/8M76932
24600163 1/26153 5/8M901511

Class 2500 Weld Neck Flange Dimensions

Size in InchSize in mmOuter DiameterFlange ThicknessHub ODWeld Neck ODWelding Neck LengthBoreRF DiameterRF HeightPCDWeld Face
ABCDEFGHIJ
1/21513530.24321.373Welding Neck bore is derived from the pipe schedule34.9788.91.6
3/42014031.85126.77942.9795.21.6
125160355733.48950.871081.6
1 1/43218538.17342.29563.57130.21.6
1 1/24020544.57948.31117371461.6
25023550.99560.312792.17171.41.6
2 1/26526557.211473143104.87196.81.6
38030566.713388.91681277228.61.6
410035576.2165114.3190157.272731.6
512542092.1203141.3229185.77323.81.6
6150485108235168.3273215.97368.31.6
8200550127305219.1318269.97438.21.6
10250675165.1375273419323.87539.81.6
12300760184.2441323.84643817619.11.6

Class 2500 Weld Neck Flange Stud & Bolt Dimensions

Size in InchSize in mmNo of BoltsBolt Size UNCRF Stud LengthHole SizeISO Stud SizeWeight in kg
1/21543/41207/8M203.3
3/42043/41257/8M203.7
12547/81401M245.5
1 1/432411501 1/8M277.8
1 1/24041 1/81701 1/4M3011.5
250811801 1/8M2719
2 1/26581 1/81951 1/4M3024
38081 1/42201 3/8M3342.8
410081 1/22551 5/8M3966
512581 3/43001 7/8M45111
6150823452 1/8M52173
82001223802 1/8M52264
10250122 1/24902 5/8M64490
12300122 3/45402 7/8M72695

Disclaimer –  Please check with ASME B16.5 Before using.

Thank You for subscribing to Hardhat Engineer. Your Ebook will Open in New Tab

HHE Subscribe Form

Use Your Genuine Email to get Updates on this Ebook in the Future.