Technical Regulations of the ANSI / ASME B16.21 Standard
The ANSI / ASME B16.21 standard establishes global requirements for the design, material selection, geometric tolerances, and marking methods for non-metallic flat gaskets. Products supplied by EV Group China fully comply with these specifications, ensuring reliable sealing of flange connections in pipeline systems for various purposes.
Classification and Structural Types of Gaskets
The choice of gasket configuration directly depends on the design features of the flange sealing surface. EV Group China engineers recommend following this classification when selecting components:
| Gasket Type | Compatible Flange Surface |
|---|---|
| Full Face | Flat Face |
| Ring | Raised Face |
Nominal Pipe Size (NPS) and Nominal Diameter (DN) Parameters
The standard uses the NPS (Nominal Pipe Size) system according to ASME B36.10M, which correlates with the international DN nominal diameter system. This allows EV Group China specialists to ensure precise compatibility of gaskets with flange fittings of global standards.
| NPS (inches) | DN (mm) |
|---|---|
| 1/2 | 15 |
| 3/4 | 20 |
| 1 | 25 |
| 1 1/4 | 32 |
| 1 1/2 | 40 |
| 2 | 50 |
| 2 1/2 | 65 |
| 3 | 80 |
| 3 1/2 | 90 |
| 4 | 100 |
For pipelines with a nominal diameter of NPS ≥ 4, the conversion to the metric system is calculated using the formula: DN = 25 × NPS.