How is the flange sealing surface type selected?
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Dear experts, what standards are used to determine the type of sealing surface for pipe flanges? Is there a specific standard that sets such requirements?
Flange standards, standards related to special equipment
Maybe I didn’t explain myself clearly. What I mean is: the design institute chose the flange type with uneven surfaces in MFM for a certain project. What I want to know is what the principles or criteria behind that choice were? Is it based on Appendix A on page 21 of HGT20592-97 or some other standard?
Some standards may mention what type is required, but there is no separate standard that specifies this. Large design firms may have specific provisions in their own design technical regulations. For flammable and explosive media, PN10MPa or class 600 and below generally use RF, while those above use RJ. The previous standard for liquefied petroleum gas required the use of MFM, but it seems that requirement has also been removed now. As for highly toxic and extremely toxic substances, I’m not sure; I’ve never been exposed to them. One could look at the specific standards for such substances.