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?

1-Do you agree with me? Is it a common size among manufacturers?
Yes I agree with you that this is not one of the more common sizes. See this link for both common and uncommon pipe sizes.
http://www.maselmon.com/Content.aspx?ContentID=24
22" pipe is not shown on this list, but it might be made or can be made by someone as a custom item at a very high cost. The more important question and the logic for NOT using it is the fact that you will not be able to find 22" FITTINGS, FLANGES, GASKETS and VALVES in the same size and schedule.

2-Can piping change the size to 24" or shall piping obey process?
Piping should make every effort to point out the economical reasons for changing to a more common and more readily available piping size.

3-If process wants to add this size to PMS , piping shall follow it?
No!

4-Could you please list rare sizes to me?
The more rare pipe sizes shown on the chart I included above are:
NPS --- DN
1 1/4 --- 32
2 1/2 --- 65
3 1/2 --- 90
5 ----- 125

thanks alot Mr.Job

your answer is complete.
but there is pipe size upto 96" in this project , so i want to know all uncommon sizes upto 96".
in that link you said , only there are upto 36".
could you please highlight rare sizes upto 96" or in a way that rare sizes indicated clearly?

So far I have only found sizes up to 88" (DN 2200)


DN Nominal Pipe Size
(mm) NPS(inches)
15 -- 1/2
20 -- 3/4
25 -- 1
40 -- 1 1/2
50 -- 2
80 -- 3
100 - 4
150 - 6
200 - 8
250 - 10
300 - 12
350 - 14
400 - 16
450 - 18
500 - 20
600 - 24
650 - 26
700 - 28
750 - 30
800 - 32
900 - 36
1000 - 40
1050 - 42
1100 - 44
1200 - 48
1300 - 52
1400 - 56
1500 - 60
1600 - 64
1700 - 68
1800 - 72
1900 - 76
2000 - 80
2200 - 88



Also check out this web site: http://www.e-pipe.co.kr/eng/API/api5l.htm

thanks alot for your help