Industry Standard Class 250 Welding Neck Flanges

Nominal Pipe Size	Outside Diameter (O)	Thickness (T)	Raised Face Diameter (R)	Length Thru Hub (Y)	Base of Hub Diameter (X)	Diameter of Hub at Bevel (A)	Bore (B)	Approximate Weight	Bolt Circle (C)	Number of Holes	Diameter of Bolt Holes
26	38.25 mm	2.81 mm	32.44 mm	5.81 mm	30.50 mm	N/A	Specified by purchaser	530 lb	34.50 mm	28	1.88 mm
28	40.75 mm	2.94 mm	34.94 mm	5.94 mm	33.00 mm	N/A	Specified by purchaser	630 lb	37.00 mm	28	1.88 mm
30	43.00 mm	3.00 mm	37.19 mm	6.00 mm	35.25 mm	N/A	Specified by purchaser	700 lb	39.25 mm	28	1.88 mm
32	45.25 mm	3.12 mm	39.44 mm	6.13 mm	37.50 mm	N/A	Specified by purchaser	790 lb	41.50 mm	28	1.88 mm
34	47.50 mm	3.25 mm	41.44 mm	6.25 mm	39.50 mm	N/A	Specified by purchaser	880 lb	43.50 mm	28	1.88 mm
36	50.00 mm	3.38 mm	43.69 mm	6.38 mm	41.50 mm	N/A	Specified by purchaser	970 lb	46.00 mm	32	2.13 mm
38	52.25 mm	3.44 mm	45.69 mm	6.44 mm	43.50 mm	N/A	Specified by purchaser	1050 lb	48.00 mm	32	2.13 mm
40	54.50 mm	3.56 mm	47.94 mm	6.56 mm	45.75 mm	N/A	Specified by purchaser	1150 lb	50.25 mm	36	2.13 mm
42	57.00 mm	3.69 mm	50.44 mm	6.94 mm	47.75 mm	N/A	Specified by purchaser	1325 lb	52.75 mm	36	2.13 mm
44	59.25 mm	3.75 mm	52.69 mm	7.00 mm	49.75 mm	N/A	Specified by purchaser	1425 lb	55.00 mm	36	2.13 mm
46	61.50 mm	3.88 mm	54.94 mm	7.13 mm	51.75 mm	N/A	Specified by purchaser	1525 lb	57.25 mm	40	2.13 mm
48	65.00 mm	4.00 mm	58.44 mm	7.25 mm	54.00 mm	N/A	Specified by purchaser	1825 lb	60.75 mm	40	2.13 mm

Quick Links