Dimensions of Class 300 RF Orifice WN Flanges as per ASME B16.36.
All other dimensions are in "inches" unless noted otherwise.

Dimensions of Orifice WN Flanges

NPS
inch
OD
of
Flange
(O)
Dia
of
Raised
Face
(R)
Min
Thk
of
Flange
(T)
Weld
Neck
Length
(Y)
Hub
Dia
at
Base
(X)
Hub
Dia
at
End
(A)
Weld
Neck
Bore
(B)
Dia
of
Tap
(Tt)

Bolt
Circle
Dia

No.
of
Bolt
Holes
Dia
of
Bolt
Holes
Dia
of
Bolts
Stud
Bolt
Length
1 4.88 2 1.50 3.25 2.12 1.32 (1) 1/4 3.50 4 0.69 5/8 5
1-1/2 6.12 2.88 1.50 3.38 2.75 1.90 (1) 1/4 4.50 4 0.81 3/4 5.25
2 6.50 3.62 1.50 3.38 3.31 2.38 (1) 1/4 5 8 0.69 5/8 5
2-1/2 7.50 4.12 1.50 3.50 3.94 2.88 (1) 1/4 5.88 8 0.81 3/4 5.25
3 8.25 5 1.50 3.50 4.62 3.50 (1) 3/8 6.62 8 0.81 3/4 5.25
4 10 6.19 1.50 3.62 5.75 4.50 (1) 1/2 7.88 8 0.81 3/4 5.25
6 12.50 8.50 1.50 3.94 8.12 6.63 (1) 1/2 10.62 12 0.88 3/4 5.25
8 15 10.62 1.62 4.38 10.25 8.63 (1) 1/2 13 12 1 7/8 5.75
10 17.50 12.75 1.88 4.62 12.62 10.75 (1) 1/2 15.25 16 1.12 1 6.50
12 20.50 15 2 5.12 14.75 12.75 (1) 1/2 17.75 16 1.25 1-1/8 7
14 23 16.25 2.12 5.62 16.75 14 (1) 1/2 20.25 20 1.25 1-1/8 7.25
16 25.50 18.50 2.25 5.75 19 16 (1) 1/2 22.50 20 1.38 1-1/4 7.75
18 28 21 2.38 6.25 21 18 (1) 1/2 24.75 24 1.38 1-1/4 8
20 30.50 23 2.50 6.38 23.12 20 (1) 1/2 27 24 1.38 1-1/4 8.50
24 36 27.25 2.75 6.62 27.62 24 (1) 1/2 32 24 1.62 1-1/2 9.50

Note - (1) : Bore diameter of Orfice Flange (B) shall be specified by Purchaser.