Some questions regarding the HG20609 metal-clad gasket
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RT: (1) HG20609 specifies that metal-clad gaskets can be used in pressure ranges from PN25 to PN100; in other words, if metal-clad gaskets are to be used, the nominal pressure of the flange must be at least PN25. Flanges with a lower nominal pressure cannot use such gaskets. The applicable pressure range for metal-clad gaskets according to GB/T15601 is from PN2.5 to PN63. Moreover, GB/T15601 is listed as a reference standard in HG20609, which means that HG20609 actually draws on some of the content of GB/T15601. Then why do these two standards have different specifications regarding the nominal pressure range of flanges that can be used with metal-clad gaskets for PN-series pipe flanges? (2) Can gaskets specified by GB/T15601 be used with WN-RF flanges of HG20592 PN16?
National standards take precedence over industry standards.
It’s rare to use metal-clad gaskets, right? May I ask in what situation did the original poster use them?
Apart from the mandatory standards, all other standards have the same status and there is no priority order. A standard, once adopted, is a set of rules that must be followed.
1. The applicability of a standard has a certain scope, which is generally specified in the preamble or the first chapter of the standard； 2. HG flanges, gaskets, and fasteners form a unified system; they should generally be selected within the HG standard, and it is not advisable to use components from different standards. HG/T 20609 specifies the standards and requirements for metal-clad gaskets applicable to pipe flanges of PN25-PN63 levels; it does not impose any application restrictions on the metal-clad gaskets themselves. 4. GB/T 15601 is a gasket standard; whether it can be used depends on the references specified in the design specifications or product standards. 5. HG/T 20592 specifies the corresponding requirements for selecting HG gaskets; see Chapter 5 for details. 6. Whether GB/T 15601 is applicable to the pipe flanges specified in HG/T 20592 requires checking whether the dimensions of the sealing surface of the pipe flanges are suitable for the gaskets (mainly the dimensions of the raised surface); from a sealing performance perspective, it is feasible.