ANSI B16.5 Class 2500 Forged Flanges

Weld Neck Forged Flange

Threaded Forged Flange

Lap Joint Forged Flange

Blind Forged Flange

Nom. Pipe Size	O	T	R	X	#/Dia of Holesa	Bolt Circle Dia	B2b	B3	H	L	L2	L3	r	C	Thr
½	5.25	1.19	1.38	1.69	4-0.88	3.5		0.9	0.84	1.56	2.88	1.56	0.12	0.93	1.12
¾	5.5	1.25	1.69	2	4-0.88	3.75		1.11	1.05	1.69	3.12	1.69	0.12	1.14	1.25
1	6.25	1.38	2	2.25	4-1.00	4.25		1.38	1.32	1.88	3.5	1.88	0.12	1.41	1.38
1¼	7.25	1.5	2.5	2.88	4-1.12	5.13		1.72	1.66	2.06	3.75	2.06	0.19	1.75	1.5
1½	8	1.75	2.88	3.12	4-1.25	5.75		1.97	1.9	2.38	4.38	2.38	0.25	1.99	1.75
2	9.25	2	3.63	3.75	8-1.12	6.75		2.46	2.38	2.75	5	2.75	0.31	2.5	2
2½	10.5	2.25	4.13	4.5	8-1.25	7.75		2.97	2.88	3.12	5.62	3.12	0.31	3	2.25
3	12	2.62	5	5.25	8-1.38	9		3.6	3.5	...	6.62	3.62	0.38	...	...
4	14	3	6.19	6.5	8-1.63	10.75		4.6	4.5	...	7.5	4.25	0.44	...	...
5	16.5	3.62	7.31	8	8-1.88	12.75		5.69	5.56	...	9	5.12	0.44	...	...
6	19	4.25	8.5	9.25	8-2.12	14.5		6.75	6.63	...	10.75	6	0.5	...	...
8	21.75	5	10.63	12	12-2.12	17.25		8.75	8.63	...	12.5	7	0.5	...	...
10	26.5	6.5	12.75	14.75	12-2.63	21.25		10.92	10.75	...	16.5	9	0.5	...	...
12	30	7.25	15	17.38	12-2.88	24.38		12.92	12.75	...	18.25	10	0.5	...	...

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.