Control Valve minimum body size

[Instr13]

Hi,
In many specifications of refineries (Oil&Gas), the minimum body size of Control Valves specified as 1 in and 300# class regardless of Pipe size and specification. Could anyone give me an explanation.
I am trying to replace a 1/2" pressure regulator with a control valve therefore I am thinking of using 1/2" body control valve and 150# flange (deviating from normal practice).
Thanks.

 

[hacksaw]

it has to do with valve body/piping strength in an operating environment, fire protection, and a desire to minimize the stocking of fractional sizes. the flange ratings are another matter.

if you are in a process line stick with the spec.

 

[ilan7]

Think you can live with evry one in peace by using a reduce port 1" V-ball valve or using a 1" globe valve with low Cv value. (for 1/2" control valve a butterfly is out of the question anyway).