Regarding the selection of instruments/valves (pressure rating).
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The standard for pipeline flanges follows HG/T20592-2009A RF, but it seems that the standards for domestically produced instruments or valves use the B series. So, what impact does it have when both imperial and metric systems are used in the same project?
The nominal diameter of the flanges is different, right? It’s fine if the diameter is smaller; but with larger diameters, it becomes difficult to connect the pipe fittings
If the gauge is in imperial units, then the matching flange must also be imperial; otherwise, it cannot be installed.
It is best to standardize everything uniformly when designing a project. It's also easier to keep track of installation accessories. It’s not that special treatments can’t be used; it’s just that their versatility is limited.