# nominal pipe sizes



## saraxo (Aug 10, 2019)

Hi All,

Do nominal pipe sizes come in odd numbers or are they always even numbers ( 4 inch, 6 inch, 8 inch, etc).

I was solving a fluid mechanics problem where two pipes were in parallel and you had to solve for the diameter of one of the pipes. I got the right answer of 4.8 inches. Based on the answer choices, I saw that both 5 inches and 6 inches were given as choices. I chose 6 because I thought that would be the next nominal size but the solution manual says the answer is 5 inches.

The problem didn't state if its a sanitary or storm sewer pipe either. Can someone clarify this to me?


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## P-E (Aug 10, 2019)

saraxo said:


> Hi All,
> 
> Do nominal pipe sizes come in odd numbers or are they always even numbers ( 4 inch, 6 inch, 8 inch, etc).
> 
> ...


1” and 3” are common sizes.   Larger pipe is generally even numbers.   5” exists but not common.  The inside and outside diameter depends on the schedule pipe (schedule  10, 40, 80, standard, etc) and sometimes material (steel, copper, ductile iron, etc)


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## pse19622 (Aug 10, 2019)

In my experience, if pipe material is not specified (e.g., Schedule 40 Steel), I use the diameter given in the problem statement. If pipe material IS specified, refer to piping tables (App 16.B in the MERM) for diameter and area (make sure to pay attention to units!).


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## Audi Driver P.E. (Aug 12, 2019)

https://en.wikipedia.org/wiki/Nominal_Pipe_Size


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## Ramnares P.E. (Aug 12, 2019)

Crane's Fluid Flow Manual is typically the source for pipe sizes, wall thickness, area etc. and was the source material used when I did process/power piping and piping distribution.


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## Pass the PE Exam (Sep 20, 2019)

In order to figure out what pipe sizes NCEES might be referring to I’d consult the reference guide they posted for the computer-based tests moving forward. Given that will be the only reference available, the available pipe sizes can likely only come from there.


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