RE: Sea Water Piping

From: <SARE>
Date: Thu May 02 2002 - 09:17:00 EDT

im sorry. paul has already reminded about using acronyms (bad habit). pccp - prestressed concrete cylinder pipe. steel cylinder core encased in conc. and wrapped with hi-strength wire strand and then coated with cement. lcc - life cycle costing. that's how our bean-counter loves to call the economic evaluation to justify capital expenditures (in this case we make comparison between replacement, mat'l upgrade, rehab or do nothing) . rca - root cause analysis. basically a reliability tool that we use whenever a loss event occurs to det. the how and why of failures. here the risk is factored in (consequence and probability)the recommendation. the stress calc and the cost analysis is just part of the analysis. by the way when we run the C2 for frp material, our acceptance criteria is very different compared with hard pipe (weeping leak).

we do use hdpe but not in sea water application.

-----Original Message-----
From: Steve McKenzie [mailto:Mechproj@xtra.co.nz] Sent: 02 May, 2002 11:49 AM
To: PipingDesign@yahoogroups.com
Subject: RE: [PipingDesign] Sea Water Piping

Hi Ralph

thanks for that.
could you expand the following acronyms: pccp
Icc
rca

Have you had any experience with polyethylene pipe in seawater?

Cheers

Steve McKenzie

-----Original Message-----
From: SARE, RALPH H. [mailto:SARERH@YANPET.SABIC.com] Sent: Thursday, May 02, 2002 8:19 PM
To: 'PipingDesign@yahoogroups.com'
Subject: [PipingDesign] Sea Water Piping

ive seen the perfromance of nickel alloys (limited to 4 nps and under), frp, pccp and mortar-lined piping (up to 114 inch dia)in sea water application. Nickel alloys are good but expensive. pccp is ok for buried line. problem is mostly confined to frp and cement-lined piping (to awwa c205). With frp the issue is related to the strenght and maintenance (repairing is a headache).
With cement-lined, problem is mostly due cracking or spalling of the cement
(our guess is shock or water hammeris the culprit) leading to corrosion
leading to leaks. ive noticed it at areas near or at cement sleeve location, branch connection and flange joints. these are the downside. its a nuisance but manageable.

We've done a study to rehab and find a long-term soln for our Cement lined piping (sea water cooling). The alterntive (such as the use of frp or other type of "plastic" pipe) has shown the same result - it failed the lcc req't. we've also run different scenario to assess the risk including rca - our conclusion always pointed to the cement-lined piping as the matl of choice
(at least for our application).

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Received on Thu May 02 09:17:00 2002