RE: [PipingDesign] Seawater Piping

From: <Steve>
Date: Thu May 16 2002 - 02:31:00 EDT


Diameter 450 or 500 O.D. Rating PN6.3 or PN8. May go to PE100.



-----Original Message-----
From: Geoff Stone DD&D Australia [] Sent: Thursday, May 16, 2002 12:40 PM
To:; Bernard Ellis Subject: Re: [PipingDesign] Seawater Piping


What diameter and class are we talking about here?

I would consider floating the pipe out as one under the jetty and winching it
up to the supports. then making the flange connections at each end. The PE 80
comes as several grades. The 80 B and the 80C are the most common. 80 B is what
is esed to be known as MDPE and the 80 C is HDPE. The problem with the latter
is that moderate temperatures will reduce the life span of the material. Why not use PE 100 which is another MDPE as this isnt affected by the service/ambient temperature.

The expansion of the PE being 15-20 times that of steel may be your biggest problem. ABS is 10 times that of steel.

The other problem is local buckling of the pipe wall where the support is if there are moderately high ambient temperatures and thin wall pipe. If the pipe
expands and the pipe has buckled locally it can end up being torn at the supports. Need to look at PTFE lining supports and having large radii at the edges.

You can prices for PE out of Eurapipe in Australia for the NEw Zealand market.
Speak to Bernard Ellis . I have added him to this email if you want to follow

Geoff Stone
--- smckennz <> wrote:



Hi Guys<BR>

I have done the gut wrenching bit associated with material decisions <BR> and am going for HDPE on this one instead of concrete lined steel as <BR> you recommended.<BR>
Delivered line price:<BR>
$US $90/m for conc/steel (12m lengths) + $US $525 per 90 deg bend + <BR> $250 (my guess, help Ralph)??? per joint <BR>

$US $71/m (12m lengths) for HDPE (PN8 PE80) + $400 per bend + $288 <BR> per joint (electrofusion).<BR>


Out of the 400m approx total length (and rising), 120m is underslung <BR> beneath a jetty. HDPE is lighter and more flexible. Exactly how we <BR> are going to do it (drop out the existing conc/steel pipe and install <BR> the PE) is still a mystery so I will add another $71/m for <BR> installation and figure it out later.<BR>

Corrosion resistance:<BR>
The site guys told me that the majority of the many failures they <BR> have had are from the outside in. I.e. failures in the steel jacket.<BR> Cant happen with PE.<BR>

Speed of Repair:<BR>
Say 2 joints + 2m replacement section.<BR> Electrofusion for cut and replace on PE- say 2 hrs (chainsaw cuts)<BR> Gibaults on concrete/steel temporary - say 2+1/2hrs (disc grinder <BR> cuts)<BR>
Concrete/steel permanent, say 5 hrs (welded straps + injected <BR> grout???)? <BR>

Your valued opinions are requested. Am I making a monkey of myself <BR> (again)?<BR>

Thanks as usual and dont be shy; I dont know where you live.<BR>


Steve McKenzie<BR>



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Received on Thu May 16 02:31:00 2002

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