Gasket dimensions for flat ring and full face applications
ASME B16.21 class 900
Nominal bore |
Flat ring and full face gasket |
Flat ring gasket |
Full face gasket |
Nominal bore |
Inner diameter |
Outer diameter |
Outer diameter |
Bolt circle diameter |
Diameter of holes |
Number of bolt holes |
Inches |
mm |
Inches |
mm |
Inches |
mm |
Inches |
mm |
Inches |
mm |
1/2 |
27/32 |
21.4 |
2 1/2 |
63.5 |
4 3/4 |
120.7 |
3 1/4 |
82.6 |
7/8 |
22.2 |
4 |
1/2 |
3/4 |
1 1/16 |
27.0 |
2 3/4 |
69.9 |
5 1/8 |
130.2 |
3 1/2 |
88.9 |
7/8 |
22.2 |
4 |
3/4 |
1 |
1 5/16 |
33.3 |
3 1/8 |
79.4 |
5 7/8 |
149.2 |
4 |
101.6 |
1 |
25.4 |
4 |
1 |
1 1/4 |
1 21/32 |
42.1 |
3 1/2 |
88.9 |
6 1/4 |
158.8 |
4 3/8 |
111.1 |
1 |
25.4 |
4 |
1 1/4 |
1 1/2 |
1 29/32 |
48.4 |
3 7/8 |
98.4 |
7 |
177.8 |
4 7/8 |
123.8 |
1 1/8 |
28.6 |
4 |
1 1/2 |
2 |
2 3/8 |
60.3 |
5 5/8 |
142.9 |
8 1/2 |
215.9 |
6 1/2 |
165.1 |
1 |
25.4 |
8 |
2 |
2 1/2 |
2 7/8 |
73.0 |
6 1/2 |
165.1 |
9 5/8 |
244.5 |
7 1/2 |
190.5 |
1 1/8 |
28.6 |
8 |
2 1/2 |
3 |
3 1/2 |
88.9 |
6 5/8 |
168.3 |
9 1/2 |
241.3 |
7 1/2 |
190.5 |
1 |
25.4 |
8 |
3 |
4 |
54 1/2 |
114.3 |
8 1/8 |
206.4 |
11 1/2 |
292.1 |
9 1/4 |
235.0 |
1 1/4 |
31.8 |
8 |
4 |
5 |
5 9/16 |
141.3 |
9 3/4 |
247.7 |
13 3/4 |
349.3 |
11 |
279.4 |
1 3/8 |
34.9 |
8 |
5 |
6 |
6 5/8 |
168.3 |
11 3/8 |
288.9 |
15 |
381.0 |
12 1/2 |
317.5 |
1 1/4 |
31.8 |
12 |
6 |
8 |
8 5/8 |
219.1 |
14 1/8 |
358.8 |
18 1/2 |
469.9 |
15 1/2 |
393.7 |
1 1/2 |
38.1 |
12 |
8 |
10 |
10 3/4 |
273.1 |
17 1/8 |
435.0 |
21 1/2 |
546.1 |
18 1/2 |
469.9 |
1 1/2 |
38.1 |
16 |
10 |
12 |
12 3/4 |
323.9 |
19 5/8 |
498.5 |
24 |
609.6 |
21 |
533.4 |
1 1/2 |
38.1 |
20 |
12 |
14 |
14 |
355.6 |
20 1/2 |
520.7 |
25 1/4 |
641.4 |
22 |
558.8 |
1 5/8 |
41.3 |
20 |
14 |
16 |
16 |
406.4 |
22 5/8 |
574.7 |
27 3/4 |
704.9 |
24 1/4 |
616.0 |
1 3/4 |
44.5 |
20 |
16 |
18 |
18 |
457.2 |
25 1/8 |
638.2 |
31 |
787.4 |
27 |
685.8 |
2 |
50.8 |
20 |
18 |
20 |
20 |
508.0 |
27 1/2 |
698.5 |
33 3/4 |
857.3 |
29 1/2 |
749.3 |
2 1/8 |
54.0 |
20 |
20 |
24 |
24 |
609.6 |
33 |
838.2 |
41 |
1041.4 |
35 1/2 |
901.7 |
2 5/8 |
66.7 |
20 |
24 |