hello experts

i am a piping designer.
i am ckecking some p&id,s that issued by process group.
there is a 22″ pipe in the output of boiler in p&id , in my opinion it seems to be incorrect ,
because this size isn,t a normal size and it is rare and there is not in PMS, so i put a comment about change it.

now ,my questions: 1-do you agree with me? is it a common size among manufacturers?
2-can piping wants from process to change size to 24″ or piping shall obey process?
3-if process wants to add this size to PMS , piping shall follow it?
3-could you please list rare sizes to me?