ANSI B16.5 Class 300 Welding Neck Flanges

- All dimensions are in inches
- These flanges will be furnished with a 1/4″ raised face unless otherwise specified.
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Nominal Pipe Size	Outside Diameter (O)	Bolt Circle (W)	Raised Face Diameter (R)	Number of Holes	Diameter of Holes	Bore (B)	Point of Weld (A)	Hub Diameter (X)	Thickness (T)	Length Thru Hub (Y)	Approximate Weight (lbs)
1/2	3.75	2.62	1.38	4	0.63	0.62	0.84	1.50	0.50	2.00	2
3/4	4.62	3.25	1.69	4	0.75	0.82	1.05	1.88	0.56	2.19	3
1	4.88	3.50	2.00	4	0.75	1.05	1.32	2.12	0.62	2.38	4
1 1/4	5.25	3.88	2.50	4	0.75	1.38	1.66	2.50	0.69	2.50	5
1 1/2	6.12	4.50	2.88	4	0.88	1.61	1.90	2.75	0.75	2.63	7
2	6.50	5.00	3.62	8	0.75	2.07	2.38	3.31	0.81	2.69	9
2 1/2	7.50	5.88	4.12	8	0.88	2.47	2.88	3.94	0.94	2.94	12
3	8.25	6.62	5.00	8	0.88	3.07	3.50	4.62	1.06	3.06	15
3 1/2	9.00	7.25	5.50	8	0.88	3.55	4.00	5.25	1.12	3.13	18
4	10.00	7.88	6.19	8	0.88	4.03	4.50	5.75	1.19	3.32	25
5	11.00	9.25	7.31	8	0.88	5.05	5.56	7.00	1.31	3.82	32
6	12.50	10.62	8.50	12	0.88	6.07	6.63	8.12	1.38	3.82	42
8	15.00	13.00	10.62	12	1.00	7.98	8.63	10.25	1.56	4.32	67
10	17.50	15.25	12.75	16	1.12	10.02	10.75	12.62	1.81	4.56	91
12	20.50	17.75	15.00	16	1.25	12.00	12.75	14.75	1.94	5.06	140
14	23.00	20.25	16.25	20	1.25	13.25	14.00	16.75	2.06	5.56	180
16	25.50	22.50	18.50	20	1.38	15.25	16.00	19.00	2.19	5.65	250
18	28.00	24.75	21.00	24	1.38	17.25	18.00	21.00	2.31	6.19	320
20	30.50	27.00	23.00	24	1.38	19.25	20.00	23.12	2.44	6.32	400
22	33.00	29.25	25.25	24	1.63	21.25	22.00	25.25	2.56	6.44	465
24	36.00	32.00	27.25	24	1.63	23.25	24.00	27.62	2.69	6.56	580