WELDING NECK FLANGES ASME B16.5 Class 400

Nominal
Size
NPS
Outside
Diameter
of
Flange
Thickness
of
Flange
Diameter
of
Raised
Face
Diameter
Of Hub
At Base
Diameter
of Hub at
Point of
Welding
Length
thru
Hub
Number of
Bolt Holes
Diameter
of
Bolt
Holes
Diameter
of
Bolts
Diameter
of
Bolt
Circle
Approx.
WeightPounds
Kg
O C R X A Y
½
¾
1
1 ¼
1 ½ Sizes ½ thru 3 ½ are identical to Class 600
2
2 ½
3
3 ½
4 in. 10.00 1.38 6.19 5.75 4.50 3.50 8 1.00  7/8 7.88 35
mm 254.00 35.10 157.20 146.10 114.30 88.90 25.40 22.2 200.20 16
5 in. 11.00 1.50 7.31 7.00 5.56 4.00 8 1.00  7/8 9.25 43
mm 279.40 38.10 185.70 177.80 141.20 101.60 25.40 22.2 235.00 20
6 in. 12.50 1.62 8.50 8.12 6.63 4.06 12 1.00  7/8 10.62 57
mm 317.50 41 1 215.90 206.20 168.40 103.10 25.40 22.2 269.70 26
8 in. 15.00 1.88 10.62 10.25 8.63 4.62 12 1.12 1 13.00 89
mm 381.00 47.80 269.70 260.40 219.20 117.30 28.40 25.4 330.20 40
10 in. 17.50 2.12 12.75 12.62 10.75 4.88 16 1.25 1 1/8 15.25 125
mm 444.50 53.80 323.90 320.50 273.10 124.00 31.80 28.6 387.40 57
12 in. 20.50 2.25 15.00 14.75 12.75 5.38 16 1.38 1 ¼ 17.75 175
mm 520.70 57.20 381.00 374.70 323.90 136.70 35.10 31.8 450.90 79
14 in. 23.00 2.38 16.25 16.75 14.00 5.88 20 1.38 1 ¼ 20.25 230
mm 584.20 60.50 412.80 425.50 355.60 149.40 35.10 31.8 514.40 104
16 in. 25.50 2.50 18.50 19.00 16.00 6.00 20 1.50 1 3/8 22.50 295
mm 647.70 63.50 469.90 482.60 406.40 152.40 38.10 34.9 571.50 134
18 in. 28.00 2 62 21.00 21.00 18.00 6.50 24 1.50 1 3/8 24.75 350
mm 711.20 66.50 533.40 533.40 457.20 165.10 38.10 34.9 628.70 159
20 in. 30.50 2.75 23.00 23.12 20.00 6.62 24 1.62 1 ½ 27.00 425
mm 774.70 69.90 584.20 587.20 508.00 168.10 41.10 38.1 685.80 193
24 in. 36.00 3.00 27.25 27.62 24.00 6.88 24 1.88 1 ¾ 32.00 620
mm 914.40 76.20 692.20 701.50 609.60 174.80 47.80 44.5 812.80 281