Pipe Supports - PIpe 'flattening' 2

[rgvrider]

I want to do a calculation for maximum span of some DN900 pipe. So far I've done a pressure calculation for pipe wall thickness and distributed beam calculation for span.

However, as the pipe is low pressure, wall thickness only needs to be 1mm.

I'd like some help pointing me to where I need to start to calculate 'flattening' of the pipe. I believe that I'll need a thicker wall thickness due to this, rather than internal pressure.

Cheers.

 

[AllHandlesTaken]

If you don't have access to FEA -

L.C. Peng's new book "Pipe Stress Engineering" outlines a few methods; and also references the Ductile Iron Pipe Research Association document "Design of Ductile Iron on Supports":

http://www.dipra.org/pdf/pipeOnSupports.pdf

and of course the classic Zick:

http://www.codeware.com/support/papers/zick.pdf

 

[racookpe1978]

Get a pipe supports catalog from a vender.

The book will have all the recommended span lengths for each schedule (wall thickness) of each type of pipe and service.

Let them do that work = You do not need to FEA or calculate that kind of problem from scratch.

(What slope are you planning for drain and or vents?)

 

[rgvrider]

Cheers AHT. Looks like some interesting reading.

racookpe, I didn't think of that. However I'm out of the schedule pipe wall thickness. Will have a look around though.

 

[racookpe1978]

Oh, true, true.
But think about it for a little bit.

You have "calculated" the ideal pipe wall thickness, and that theoretical thickness is very thin.

But you can only <b>buy</b> "scheduled" pipe in a carefully controlled, very limited number of sizes and pipe walls - unless you are like NASA (who can machine any thickness pipe they need to save launch weight on rockets, or a "deep pockets" theoretical physics lab with an infinite budget and an infinite schedule.

Back up and take your calculated thickness and look at corrosion margins, erosion margins, and a safety factor for your process fluid. Choose your material. Choose your theoretical internal diameter.

Then plan on buying the smallest pipe that exceeds your ID, that is the right material, and has a wall thickness that is larger than your minimum. Specialty fab'ed pipe is "e$$$$$$$$$$pecially exxxxxxxxxxtra exxxxxxxxxpen$ive."

 

[BigInch]

Some codes have minimum thickness to diameter ratios. Did you check it?

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[rgvrider]

racookpe1978, I'be using spiral welded pipe. Plate thickness determines actual thickness.

 

[MJCronin]

rgv....

What is your diameter, wall thickness, material and design pressure ?

-MJC