Sorry if there's another post relating to this. I searched but couldn't find any. The vast majority of chemcial sites that i've been to or worked at use flagned 150# stainless ball valve with some form of soft seat for process lines. One site I visited is using plug valves for process instead of ball. No one could give me a good reason for why they're using the plug vs ball. Can anyone give me their 2 cents on why you would use one over the other?