NONMETALLIC FLAT RING GASKET DIMENSIONS FOR CLASS 250 CAST IRON FLANGES

Nonmetallic flat ring gasket dimensions for ASME/ANSI B16.1 Class 250 cast iron pipe flanges and flanged fittings per ASME B16.21.

Flat Ring Gasket Dimensions for Class 250 Cast Iron Pipe Flanges (inches)
NPS	Gasket ID	Gasket OD
1	1.31	2.88
1 1/4	1.66	3.25
1 1/2	1.91	3.75
2	2.38	4.38
2 1/2	2.88	5.12
3	3.50	5.88
3 1/2	4.00	6.50
4	4.50	7.12
5	5.56	8.50
6	6.62	9.88
8	8.62	12.12
10	10.75	14.25
12	12.75	16.62
14	14.00	19.12
16	16.00	21.25
18	18.00	23.50
20	20.00	25.75
24	24.00	30.50
30	30.00	37.50
36	36.00	44.00
42	42.00	50.75
48	48.00	58.75

Notes:

NPS - Nominal Pipe Size, OD - Outer Diameter, ID - Inner Diameter