Can the pressure ratings of the inlet and outlet flanges of a safety valve be the same?

There is nothing wrong with using high-voltage equipment in low-voltage conditions.

Of course, using a higher level on a lower level is definitely no problem at all

It can be used without problems, but there are issues with matching, mainly regarding the matching of bolt holes, connectors, etc.

The outlet flange can be the same as the inlet flange (subject to special requirements); the pipeline mating flange is the same as the outlet flange, but the grade of the outlet pipeline should be selected based on the actual design pressure (otherwise it will be a waste)

This situation is also common; generally, when the safety valve has back pressure or when it is necessary to recover the medium from the container, the flange at the outlet end of the safety valve can be of the same grade as that at the inlet end. The prices will vary.

The inlet and outlet pressure ratings of the safety valve can be customized as long as they meet the calculation requirements； The main issue at present is cost. Generally, the import pressure is high while the export pressure is low. Manufacturers have standard grinding tools, which result in lower costs; if custom grinding tools are required, it’s not a problem for large batches, but the cost becomes very high for small batches. Moreover, larger manufacturers are unlikely to design custom grinding tools for you, making things difficult. Therefore, the exit pressure of safety valves is usually set according to the recommendations of the manufacturer. There are some differences between the safe pressure and temperature ratings and those of flanges; safety valves can be used with flanges of a lower pressure rating. In such cases, it’s necessary to involve personnel skilled in stress calculations, as well as add support structures to the pipeline to meet the stress requirements.