Trim selection is generally based on the following key factors; 1.Application/service 2. Temperature 3.Cost effective
Suppose if you consider gate valves per API standard we have Trim 1, Trim 8, Trim 5 and more which represents different overlays for each trim with difference in cost which shall be selected based on requirement/application.
To add, Selection of Trim is very essential as it forms the bridge inbetween two internal parts which has possibility to erode and damage parts if the trim material is not supporting for the typical process.
My advice is to contact one or preferably two good, renowned actual local suppliers, give them the process conditions, and ask for a preliminary unbinding offer in two alternatives of trim detail, both to be guaranteed, but one better than the other. Ask also for references and comments on difference between the choices regarding dependability and lifetime.
In my opinion to describe function and expected lifetime will often give you a better choice in options than trying to describe details from classification papers without knowing the market's availability of products.
Choosing a correct trim is often more imporant than getting the body material right, so pay special attention. At the bottom of the following page you find the API trim chart for valves.
Good luck!
Heather Smith Alloy valves from The Alloy Valve Stockist
