Control Valves' Pressure Rating
Control Valves' Pressure Rating
(OP)
Is there a technical reason why most companies specify a minimum 300 rating for control valves below certain sizes ?
Is there any code that prohibits the use of 150 rating for 1 inch control valves ?
Is there any code that prohibits the use of 150 rating for 1 inch control valves ?





RE: Control Valves' Pressure Rating
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RE: Control Valves' Pressure Rating
There was no Code involvement in this issue at all.
You wrote:"why [do] most companies specify a minimum 300 rating"
There are Companies who are Control Valve "makers", there are Companies who are Control Valve "specifiers" and there are Companies who are Control Valve "users".
Now which of these are you talking about?
Based on my experience, the CV "makers" saw little potential demand for Class 150 Control Valves. Therefore they did not want to make a wide range of sizes and then be stuck with them gathering dust on the shelf.
So they made their starting point the Class 300 valve and the "specifiers" and "users" adjusted as required. It has worked just fine for hundreds of years.
Sometimes its possible to do all the right things and still get bad results
RE: Control Valves' Pressure Rating
RE: Control Valves' Pressure Rating
RE: Control Valves' Pressure Rating
I think pennpiper has nailed it and there is no code issue I am aware and like a lot of things logic is buried in the past and if you want Class 150 you will get it if you pay the premium as the makers don't tend to produce. I have not seen Class 150 used in smaller sizes only large bore and even then only occasionally but there is no reason not to use as long as actuator can be fitted.
RE: Control Valves' Pressure Rating
isn't the rating determined solely by the design pressure and temperature ?
What is the relation between size and rating and such service ?
RE: Control Valves' Pressure Rating
"Whom the gods would destroy, they first make mad "
RE: Control Valves' Pressure Rating
RE: Control Valves' Pressure Rating