ANSI / ASME B16.5 Class 900 Lap Joint Flange Dimensions

Nominal Pipe Size	Outside Diameter (O)	Thickness (T)	Length Thru Hub (Y)	Hub Diameter (X)	Radius (r)	Bore (B)	Approximate Weight (lbs)	Bolt Circle (C)	Number of Holes	Diameter of Holes
1/2	4.75	0.88	1.38	1.25	0.13	1.50	0.90	4	3.25	4
3/4	5.13	1.00	1.69	1.38	0.13	1.75	1.11	5	3.50	4
1	5.88	1.13	2.00	1.63	0.13	2.06	1.38	8	4.00	4
1 1/4	6.25	1.13	2.50	1.63	0.19	2.50	1.72	9	4.38	4
1 1/2	7.00	1.25	2.88	1.75	0.25	2.75	1.97	12	4.88	4
2	8.50	1.50	3.63	2.25	0.31	4.13	2.46	25	6.50	8
2 1/2	9.63	1.63	4.13	2.50	0.31	4.88	2.97	35	7.50	8
3	9.50	1.50	2.13	5.00	0.38	3.60	25	7.50	8	1.00
4	11.50	1.75	2.75	6.25	0.44	4.60	51	9.25	8	1.25
5	13.75	2.00	3.13	7.50	0.50	5.69	81	11.00	8	1.38
6	15.00	2.19	3.38	9.25	0.50	6.75	105	12.50	12	1.25
8	18.50	2.50	4.50	11.75	0.50	8.75	190	15.50	12	1.50
10	21.50	2.75	5.00	14.50	0.50	10.92	275	18.50	16	1.50
12	24.00	3.13	5.63	16.50	0.50	12.92	370	21.00	20	1.50
14	25.25	3.38	6.13	17.75	0.50	14.18	415	22.00	20	1.63
16	27.75	3.50	6.50	20.00	0.50	16.19	465	24.25	20	1.75
18	31.00	4.00	7.50	22.25	0.50	18.20	650	27.00	20	2.00
20	33.75	4.25	8.25	24.50	0.50	20.25	810	29.50	20	2.13
24	41.00	5.50	10.50	29.50	0.50	24.25	1550	35.50	20	2.63

*Use 25.4 as a factor to convert into mm.