Pipeline Fittings

Saheeb...

You have some problems...

The first problem is, of course, you do not understand the concept of piping line specifications, piping engineering and design.

The second problem is a large difference between the operating pressure and the design pressure in this piping system

Valve ratings and flanges are selected based on design pressure, not operating pressure.

You will be selecting and purchasing much more expensive valves and flanged components based on a design pressure of 725 psig. ( probably class 900).

If you were to use a more realistic design pressure of 325 - 350 psig, a more realistic pipe clas ( say Class 300) could be purchased.

And I believe you do not know what is the ANSI pressure rating. For the design pressure of 725 psig at 50°C you can use ANSI 300# pressure rating

What? More homework, look at the specs. If that fails and you can select an or equal from the Engineers references for pipe and valves. Clearly you are not qualified to have any control over the work as you can't even tell us what the nature of the material that will pass through the pipe/valve consists of. I suggest that you enroll in a different course, possibly basket weaving and left over beer straining.

TMF

Valve ratings and flanges are selected based on design pressure, not operating pressure.

What is the pipe wt? What is its OD?

In pipelines, normally we do not use flanged valves, we prefer welded valves on line, rated at design pressure.