TSI offers API ring joint gaskets in two basic types, an oval cross section and an octagonal cross section. These basic shapes are used in pressures up to 10,000 PSI. The dimensions are standardized and require specially grooved flanges.

The octagonal crosss section has a higher sealing efficiency than the oval and would be the preferred gasket. The hardness of the ring should always be less than the hardness of the flanges. Dimensions for API ring joint gaskets and grooves are covered in ANSI B.16.20 and API 6A.

API ring gaskets
MaterialDesignationMax Hardness
Rockwell B
Max Hardness
Brinell
Soft Iron D 56 90
Low Carbon Steel S 68 120
4-6 Chrome F-5 72 130
304 Stainless Steel S304 83 160
316 Stainless Steel S316 83 160
347 Stainless Steel S347 83 160
410 Stainless Steel S410 86 170
SizePSI RatingNo.Soft Iron Part No.Stainless Part No. SizePSI RatingNo.Soft Iron Part No.Stainless Part No.
1-13/16 10/20M BX-151 RGSTBX-151 RGSS316BX-151   2-1/16 2000 R-23 RGSTR-23 RGSS316R-23
2-1/16 10/20M BX-152 RGSTBX-152 RGSS316BX-152     5000 R-24 RGSTR-24 RGSS316R-24
2-9/16 10/20M BX-153 RGSTBX-153 RGSS316BX-153   2-9/16 2000 R-26 RGSTR-26 RGSS316R-26
3-1/16 10/20M BX-154 RGSTBX-154 RGSS316BX-154     5000 R-27 RGSTR-27 RGSS316R-27
4-1/16 10/20M BX-155 RGSTBX-155 RGSS316BX-155   3-1/8 2/3000 R-31 RGSTR-31 RGSS316R-31
5-1/8 10M BX-169 RGSTBX-169 RGSS316BX-169     5000 R-35 RGSTR-35 RGSS316R-35
7-1/16 10/20M BX-156 RGSTBX-156 RGSS316BX-156   4-1/16 2/3000 R-37 RGSTR-37 RGSS316R-37
9 10/15M BX-157 RGSTBX-157 RGSS316BX-157     5000 R-39 RGSTR-39 RGSS316R-39
11 10/20M BX-158 RGSTBX-158 RGSS316BX-158   5-1/8 2/3000 R-41 RGSTR-41 RGSS316R-41
13-5/8 5M BX-160 RGSTBX-160 RGSS316BX-160     5000 R-44 RGSTR-44 RGSS316R-44
  10/20M BX-159 RGSTBX-159 RGSS316BX-159   7-1/16 2/3000 R-45 RGSTR-45 RGSS316R-45
16-3/4 5/10M BX-162 RGSTBX-162 RGSS316BX-162     5000 R-46 RGSTR-46 RGSS316R-46
18-3/4 5M BX-163 RGSTBX-163 RGSS316BX-163   9 2/3000 R-49 RGSTR-49 RGSS316R-49
18-3/4 10/15M BX-164 RGSTBX-164 RGSS316BX-164     5000 R-50 RGSTR-50 RGSS316R-50
21-1/4 5M BX-165 RGSTBX-165 RGSS316BX-165   11 2/3000 R-53 RGSTR-53 RGSS316R-53
  10M BX-166 RGSTBX-166 RGSS316BX-166     5000 R-54 RGSTR-54 RGSS316R-54
26-3/4 2M BX-167 RGSTBX-167 RGSS316BX-167   13-5/8 2/3000 R-57 RGSTR-57 RGSS316R-57
26-3/4 3M BX-168 RGSTBX-168 RGSS316BX-168   16-3/4 2000 R-65 RGSTR-65 RGSS316R-65
              3000 R-66 RGSTR-66 RGSS316R-66
            20-3/4 2000 R-73 RGSTR-73 RGSS316R-73
            21-1/4 3000 R-74 RGSTR-74 RGSS316R-74