ANSI / ASME B16.5 Class 300 Weld Neck Flange Dimensions

Nominal Pipe Size	Outside Diameter (O)	Thickness (T)	Raised Face Diameter (R)	Length Thru Hub (Y)	Point of Weld (A)	Hub Diameter (X)	Bore (B)	Approximate Weight (lbs)	Bolt Circle (C)	Number of Holes	Diameter of Holes
1/2	3.75	0.56	1.38	2.06	0.84	1.50	0.62	2	2.63	4	0.63
3/4	4.63	0.63	1.69	2.25	1.05	1.88	0.82	3	3.25	4	0.75
1	4.88	0.69	2.00	2.44	1.32	2.13	1.05	4	3.50	4	0.75
1 1/4	5.25	0.75	2.50	2.56	1.66	2.50	1.38	5	3.88	4	0.75
1 1/2	6.13	0.81	2.88	2.69	1.90	2.75	1.61	7	4.50	4	0.88
2	6.50	0.88	3.63	2.75	2.38	3.31	2.07	9	5.00	8	0.75
2 1/2	7.50	1.00	4.13	3.00	2.88	3.94	2.47	12	5.88	8	0.88
3	8.25	1.13	5.00	3.13	3.50	4.63	3.07	15	6.63	8	0.88
3 1/2	9.00	1.19	5.50	3.19	4.00	5.25	3.55	18	7.25	8	0.88
4	10.00	1.25	6.19	3.38	4.50	5.75	4.03	25	7.88	8	0.88
5	11.00	1.38	7.31	3.88	5.56	7.00	5.05	32	9.25	8	0.88
6	12.50	1.44	8.50	3.88	6.63	8.13	6.07	42	10.63	12	0.88
8	15.00	1.63	10.63	4.38	8.63	10.25	7098	67	13.00	12	1.00
10	17.50	1.88	12.75	4.63	10.75	12.63	10.02	91	15.25	16	1.13
12	20.50	2.00	15.00	5.13	12.75	14.75	12.00	140	17.75	16	1.25
14	23.00	2.13	16.25	5.63	14.00	16.75	13.25	180	20.25	20	1.25
16	25.50	2.25	18.50	5.75	16.00	19.00	15.25	250	22.50	20	1.38
18	28.00	2.38	21.00	6.25	18.00	21.00	17.25	320	24.75	24	1.38
20	30.50	2.50	23.00	6.38	20.00	23.13	19.25	400	27.00	24	1.38
22	33.00	2.63	25.25	6.50	22.00	25.25	21.25	465	29.25	24	1.63
24	36.00	2.75	27.25	6.63	24.00	27.63	23.25	580	32.00	24	1.63

*Use 25.4 as a factor to convert into mm.