Pressure Rating Requires change? Decline 270 meter Head

[HnAw]

i have main line in a decline 1700 meters lenght, with 270 meters head until end of main, it has hose cabinet each 40 meters lng, i'm putting pressure regulating valve but im not changing rating valves 175 lb nor flanges 150#, due i'm using PRV,is necessary change to 300# rating?

 

[HnAw]

i mean , this main line goes down throw decline along 1500 mts, with 270 mts static head in the end of line, i'm adding 4 PRV , but valves like butterfly (300 psi max ope) angular and gates ( 175 lb) and flange wont support static pressure, i'm trusting PRV will sustain down 175 psi. and avoid fails. Is correct suppose this escenary?