SPIRALTEC GASKET CO.
Style WRI Inner Rings
Standard Inside Diameters to ASME B16.20
To Suit ASME B16.50 Flanges
In accordance with ASME B16.20, Inner Rings are mandatory for the following flange designations:
- Class 900 – NPS 24 to 48
- Class 1500 – NPS 12 to NPS 24
- Class 2500 – NPS 4 to NPS 12
Also: per ASME B16.20a 2000 3.2.5
Inner Rings shall be furnished wit all spiral wound gaskets having PTFE filler material. it is recommended that inner rings be specified by the user for flexible graphite and other filler materials (if appropriate for flanges and bore size used). Particularly where experience has demonstrated inward buckling of the gaskets to be a problem
| Nom. Pipe Size | Inner Ring Inside Diameter | ||||||
|---|---|---|---|---|---|---|---|
| Class 150 | Class 300 | Class 400 | Class 600 | Class 900 | Class 1500 | Class 2500 | |
| ½ | 0.56 | 0.56 | 0.56 | 0.56 | 0.56 | 0.56 | 0.56 |
| ¾ | 0.81 | 0.81 | 0.81 | 0.81 | 0.81 | 0.81 | 0.81 |
| 1 | 1.06 | 1.06 | 1.06 | 1.06 | 1.06 | 1.06 | 1.06 |
| 1 ¼ | 1.50 | 1.50 | 1.50 | 1.50 | 1.31 | 1.31 | 1.31 |
| 1 ½ | 1.75 | 1.75 | 1.75 | 1.75 | 1.63 | 1.63 | 1.63 |
| 2 | 2.19 | 2.19 | 2.19 | 2.19 | 2.06 | 2.06 | 2.06 |
| 2 ½ | 2.62 | 2.62 | 2.62 | 2.62 | 2.50 | 2.50 | 2.50 |
| 3 | 3.19 | 3.19 | 3.19 | 3.19 | 3.10 | 3.10 | 3.10 |
| 4 | 4.19 | 4.19 | 4.04 | 4.04 | 4.04 | 3.85 | 3.85 |
| 5 | 5.19 | 5.19 | 5.05 | 5.05 | 5.05 | 4.90 | 4.90 |
| 6 | 6.19 | 6.19 | 6.10 | 6.10 | 6.10 | 5.80 | 5.80 |
| 8 | 8.50 | 8.50 | 8.10 | 8.10 | 7.75 | 7.75 | 7.75 |
| 10 | 10.56 | 10.56 | 10.05 | 10.05 | 9.69 | 9.69 | 9.69 |
| 12 | 12.50 | 12.50 | 12.10 | 12.10 | 11.50 | 11.50 | 11.50 |
| 14 | 13.75 | 13.75 | 13.50 | 13.50 | 12.63 | 12.63 | |
| 16 | 15.75 | 15.75 | 15.35 | 15.35 | 14.75 | 14.50 | |
| 18 | 17.69 | 17.69 | 17.25 | 17.25 | 16.75 | 16.75 | |
| 20 | 19.69 | 19.69 | 19.25 | 19.25 | 19.00 | 18.75 | |
| 24 | 23.75 | 23.75 | 23.25 | 23.25 | 23.25 | 22.75 | |