ANSI / ASME B16.5 Class 150 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	3.50	0.44	1.38	1.88	0.84	1.19	0.62	2	2.38	4	0.63
3/4	3.88	0.50	1.69	2.06	1.05	1.50	0.82	2	2.75	4	0.63
1	4.25	0.56	2.00	2.19	1.32	1.94	1.05	3	3.13	4	0.63
1 1/4	4.63	0.63	2.50	2.25	1.66	2.31	1.38	3	3.50	4	0.63
1 1/2	5.00	0.69	2.88	2.44	1.90	2.56	1.61	4	3.88	4	0.63
2	6.00	0.75	3.63	2.50	2.38	3.06	2.07	6	4.75	4	0.75
2 1/2	7.00	0.88	4.13	2.75	2.88	3.56	2.47	8	5.50	4	0.75
3	7.50	0.94	5.00	2.75	3.50	4.25	3.07	10	6.00	4	0.75
3 1/2	8.50	0.94	5.50	2.81	4.00	4.81	3.55	12	7.00	8	0.75
4	9.00	0.94	6.19	3.00	4.50	5.31	4.03	15	7.50	8	0.75
5	10.00	0.94	7.31	3.50	5.56	6.44	5.05	19	8.50	8	0.88
6	11.00	1.00	8.50	3.50	6.63	7.56	6.07	24	9.50	8	0.88
8	13.50	1.13	10.63	4.00	8.63	9.69	7.98	39	11.75	8	0.88
10	16.00	1.19	12.75	4.00	10.75	12.00	10.02	52	14.25	12	1.00
12	19.00	1.25	15.00	4.50	12.75	14.38	12.00	80	17.00	12	1.00
14	21.00	1.38	16.25	5.00	14.00	15.75	13.25	110	18.75	12	1.13
16	23.50	1.44	18.50	5.00	16.00	18.00	15.25	140	21.25	16	1.13
18	25.00	1.56	21.00	5.50	18.00	19.88	17.25	150	22.75	16	1.25
20	27.50	1.69	23.00	5.69	20.00	22.00	19.25	180	25.00	20	1.25
22	29.50	1.81	25.25	5.88	22.00	24.25	21.25	225	27.25	20	1.38
24	32.00	1.88	27.25	6.00	24.00	26.13	23.25	260	29.50	20	1.38

*Use 25.4 as a factor to convert into mm.