Class 900 ANSI B16.5 Forged Flanges

Weld Neck Flange

Threaded Flange

Slip On Flange

Lap Joint Flange

Blind Flange

(Click any image above to enlarge it and lock it in place, then scroll to the bottom table for dimensions)
Nom. Pipe Size O T R X #/Dia of Holesa Bolt Circle Dia B B2b B3 H L L2 L3c r C Thr
Sizes 1/2″ through 2 1/2″ are identical to class 1500.
3 9.5 1.5 5 5 8-1.00 7.5 3.57  flanges, flange, industrial flanges, industrial flange, industrial pipe flanges, industrial fittings, industrial pipe, industrial carbon steel, industrial blind, industrial blinds, industrial, industrial waterworks, industrial stainless steel, industrial steel, industrial weld, industrial forgings, industrial orifice, industrial slip, industrial steel flange, industrial steel flanges, industrial titanium flange, industrial titanium flanges 3.6 3.5 2.12 4 2.12 0.38 3.63 1.62
4 11.5 1.75 6.19 6.25 8-1.25 9.25 4.57 4.6 4.5 2.75 4.5 2.75 0.44 4.63 1.88
5 13.75 2 7.31 7.5 8-1.38 11 5.66 5.69 5.56 3.12 5 3.12 0.44 5.69 2.12
6 15 2.19 8.5 9.25 12-1.25 12.5 6.72 6.75 6.63 3.38 5.5 3.38 0.5 6.75 2.25
8 18.5 2.5 10.63 11.75 12-1.50 15.5 8.72 8.75 8.63 4 6.38 4.5 0.5 8.75 2.5
10 21.5 2.75 12.75 14.5 16-1.50 18.5 10.88 10.92 10.75 4.25 7.25 5 0.5 10.88 2.81
12 24 3.12 15 16.5 20-1.50 21 12.88 12.92 12.75 4.63 7.88 5.62 0.5 12.94 3
14 25.25 3.38 16.25 17.75 20-1.63 22 14.14 14.18 14 5.12 8.38 6.12 0.5 14.19 3.25
16 27.75 3.5 18.5 20 20-1.75 24.25 16.16 16.19 16 5.25 8.5 6.5 0.5 16.19 3.38
18 31 4 21 22.25 20-2.00 27 18.18 18.2 18 6 9 7.5 0.5 18.19 3.5
20 33.75 4.25 23 24.5 20-2.13 29.5 20.2 20.25 20 6.25 9.75 8.25 0.5 20.19 3.62
24 41 5.5 27.25 29.5 20-2.63 35.5 24.25 24.25 24 8 11.5 10.5 0.5 24.19 4

Dimensions are in inches.

(a)- Bolt hole diameter 1/8 in. larger than bolt diameter.
(b)- Standard bore dimensions provided. See bore chart for other wall thicknesses.
(c)- This dimension is commonly associated with “true” lap joints. Industry standard is to make to the slip on length through the hub.

ANSI B16.5 Class 900 Forged Flange PDF (for printing).