How Do Common Flanges Divide Pressure Levels

- Feb 25, 2021-

Common flanges are used in different places, so the pressure levels are different to a certain extent. For example, large stainless steel flanges are mainly used in high temperature resistant pipelines in chemical engineering, so their material has high pressure bearing performance. Claim.
Therefore, customers often require forged flanges, because the material has been forged to increase the density of the structure and also enhance its pressure-bearing capacity.


There are clear grade requirements for the compression resistance of large stainless steel flanges in domestic and international standards. Large stainless steel flanges are generally divided into: PN25, PN6, PN10, PN16, PN25, PN40, and so on. Among them, PN10 and PN16 are very commonly used.

How do common flanges divide pressure level

Here is an example: the design pressure of the flange of the internal pressure vessel with a safeguard valve should be determined according to the opening pressure of the safeguard valve. The design pressure is equal to or slightly greater than the opening pressure of the safeguard valve, and the opening pressure of the safeguard valve is 1.05~1.1 times the working pressure.


The working pressure is known to be 0.8MPa, then the opening pressure of the safeguard valve can be taken as 0.88MPa, so the design pressure can be taken as 0.9MPa. In this way, it is reasonable to choose a high allowable working pressure of 0.9MPa (1.0MPa grade flange) for the container pipe flange 1C4 material at 50 degrees Celsius.

How do common flanges divide pressure levels