Square Piping for Fluid Conveyance

[apieron]

Does anyone have any experience with using non-circular pipe for fluid conveyance? More specifically, square or rectangular cross section. Maybe you know of some reference material that exists.

The only standard I could find is ASME Section VIII - Division I - Mandatory Appendix 13, which is 'Vessels of Noncircular Cross Section'. However, I don't think this is appropriate.

Thanks in advance.

 

[racookpe1978]

There is no explicit reason "not to" use such a "square pipe" - but you MUST have some valid REASON to use square pipe.

What do you gain?
There are (almost) NO fittings, valves or supports available, so your "economy" of square pipe had better be very, very compelling.
Internal pressure constrains against high "square pipe" fluid pressures. Again, no explicit reason why you could not require square pipe, but there are almost reasons to use it.

 

[Frank1344]

This is just a thought:
If you use hydraulic radius (diameter)(4A/P), then you can use most of the formulaes for flow with circular section.

 

[BigInch]

[ ] requires more material to get less flux

Independent events are seldomly independent.

 

[bimr]

Don't know what you are asking about.

Channels are commonly used for civil projects such as dams, etc. You can use the standard hydraulic formulas.

Here is a link to the Hazen Williams formula for non-circular conduits:

http://www.calctool.org/CALC/eng/civil/hazen-williams_g

 

[apieron]

Thanks for the comments. I suppose I was trying to be too general in my intial post.

racookpe1978, you make a valid point. Let's just assume that the benefit I gain outweighs the additional costs.

To be more specific, we are thinking of using it for a steam line with a design pressure of 145psi. The concern is using a non-circular cross section in a pressure situation. I can't find any design standards for this application.

 

[hydtools]

If there are no design standards, then you will have to do your own calculations. If you do not calculate correctly, the non-circular cross section may become circular just before it fails in yield.

Ted

 

[racookpe1978]

Well, at 145 psig, you need to concern yourself with the loss (breaking) of the wall weld at higher pressures and temperatures as well as the "rounding" of the rectangular tube steel.

Again, it is your decision, you need to justify the extra expense as well as the loss of safety margins to your client.

 

[BigInch]

I guess you know where to get box-pipe that complies with B31.1

Independent events are seldomly independent.

 

[EnergyMix]

To be more specific, we are thinking of using it for a steam line with a design pressure of 145psi. The concern is using a non-circular cross section in a pressure situation. I can't find any design standards for this application.

Do yourself a favor. Stick with circular pipe. There's a reason people use it, as hytools alluded to.



Want to know the do's and don'ts of Eng-Tips? Read FAQ731-376.
English not your native language? Looking for some help in getting your question across to others or understanding their answers? Go to forum1529.

 

[apieron]

Thanks for the help guys.