Issues with valve and flange pressure ratings
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If the valve’s pressure rating is PN16, then is the flange PN100? Should the flange connecting to the valve be one grade lower than the valve?
The pressure ratings of the valve and the flange should be the same.
It should be consistent. Do you mean that the higher level refers to bolts and nuts?
Not only the pressure rating of the flanged valve, but also the standards adopted for the valve flanges should be consistent
Valves and flanges must be matched; otherwise, how can they be installed?
The pressure rating of the valve is also indicated by the flange rating of the valve itself; therefore, it must match the flange used to connect the valve in order to be installed
For small valves, the pressure rating of the valve body is relatively high; for example, for flanged valves with DN20/15/25 dimensions, the valve pressure rating is CL800, while the flange rating may be only CL150/300 or similar. For large-sized valves, the pressure rating indicated on the valve is the same as that of the flange.
The valve and the flange should be of the same pressure rating in order to be installed, as flanges of different pressure ratings have different dimensions. You need to understand one thing: the flange is the standard that determines the pressure rating of a pipeline. First, determine the flange’s pressure rating, and everything else will follow accordingly.
The pressure ratings of the valve and the flange should be the same
It’s just a joke – this certainly won’t work. It must match the pressure rating of the valve (with some exceptions where flanges of different pressure ratings can still be compatible, such as DN100 valves and flanges with PN10 and PN16 ratings being the same). The reason is that the pressure and specifications of the flanges differ; parameters such as the center distance between bolt holes, outer diameter, and thickness are all different (not always, but in most cases). Therefore, the pressure rating of the valve determines what the corresponding pressure rating should be for the matching flange
PN16 corresponds to 1.6 MPa, while PN100 corresponds to 10 MPa; these two cannot be welded together. Considering cost considerations, pressure ratings are generally applied in conjunction with other factors; if materials are limited, it may not be necessary to use them together, but the pressure rating still must be met. In the absence of appropriate supporting structures, different wall thicknesses make welding difficult; if the welding is not done properly, the inspection using X-rays will not be successful either. In short, it needs to be complemented