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Dimensions of Non-Metallic Flat Gaskets As Per ASME B16.21

Dimensions of Non-Metallic Flat Gaskets ASME B16.21 to be used with Raised Face flanges ASME B16.5

Non Metallic Gasket Dimensions

CLASS 150 TO 900 Size 1/2″ TO 24″

NPS	d1	d2
NPS	d1	150#	300#	400#	600#	900#
1/2	21	48	54	54	54	64
3/4	27	57	67	67	67	70
1	33	67	73	73	73	79
1-1/4	42	76	83	83	83	89
1-1/2	48	86	95	95	95	98
2	60	105	111	111	111	143
2-1/2	73	124	130	130	130.2	165
3	89	137	149	149	149	168
3-1/2	102	162	165	162	162	…
4	114	175	181	178	194	206
5	141	197	216	213	241	248
6	168	222	251	248	267	289
8	219	279	308	305	321	359
10	273	340	362	359	400	435
12	324	410	422	419	457	498
14	356	451	486	483	492	521
16	406	514	540	537	565	575
18	457	549	597	594	613	638
20	508	606	654	648	683	699
24	610	718	775	768	791	838

General notes:

Dimensions are in millimeters unless otherwise indicated.
d1 = Inside diameter.
d2 = Outside diameter.
Dimensional tolerances outside diameter NPS 12 and smaller: +0 / -1.5 mm.
Dimensional tolerances outside diameter NPS 14 and larger: +0 / -3.0 mm.
Dimensional tolerances inside diameter NPS 12 and smaller: ± 1.5 mm.
Dimensional tolerances inside diameter NPS 14 and larger: ± 3.0 mm.
Thickness (t) specified by customer.