Sea Water Service Pipeline, 316L? 2

[mufasa1]

I am a mechanical engineer at a large petrocehemical complex in Turkey. We are located on the seaside and we have decided to feed our fire water pipeline with sea water during an emergency such as lack of fresh water or very low fresh water pressure. In the project the suction line from sea to the main collector (serving three centrifugal pumps) is about 50m long. What kind of material is appropriate for the suction line? It will be full of sea water at all times. Is 316L OK? We do not want to have corrosion problem in the near future.

 

[TD2K]

What about cement lined CS pipe? We used that for our SW firewater systems on offshore platforms for the larger piping. For the smaller piping, we used some much more exotic alloy, a monel alloy if I remember correctly but that was 10+ years ago.

With 316L, my first question would be wrt stress corrosion cracking due to the chlorides in sea water.

 

[Shmulik]

In case metal pipe system required, 316L is NOT suitable specially in case of emergency operated system. Metals such as 254 SMO or 904L should be used.

 

[stanier]

Suggest you use ABS as there are many locations in Australia & SE Asia where this material is used. Checkout

http://www.eurapipe.com.au.

The company is owned by Tyco and is represented throughout the world. Pipe is avaliable up to 1000mm diameter.

I have installed many systems for use on sea water, sewage sludge, potable water etc.

No fear of stress corrosion cracking

Standards are available from

http://www.standards.com.au.

Look for AS 3518 & AS 3690. Check out the drafts as AS 3518 is under revision and you may be able to download for free.

 

[ralphsare]

for above ground application.
CS pipe EFW cement lined, coated and wrapped to awwa spec. downside is the maintenance. if the mortar lining comes loose then you will start seing and repairing leaks. at the valve-to-pipe joint, you will also expreince some flaking of the mortar lining requiring another repair/replacement. note that once you losse the cement lining its an uphill battle to just keep on monitoring the line and fixing it. OK in your case since lenght is only 50 m.

between 4-36 NPS we have started using CS pipe lined with fiberglass (glass flake such as those made by Jotun) reinforced vinyl ester resin. for the small branch connection, we have selected B43 brass annealed (too small to lined properly). so far the result is better thatn the cement lined cs pipe.

fiberglass. we have consider it (lcc is really very attractive) but decided againts it. reason - if it breaks, reparing the line is a struggle especially in a very tight area (ive been into one inside the valve pit wiht sea water ozzing out like a fountain).

ss pipe. some says that scc is a concern. well for scc to occur three things must be present - residual stress, excessive amount of chloride (well for seawater of course it must be excessive)and temperature (most of the documented failure related to scc has these properties). mode of failure is leak. there is no weld repair. either you shutdwon the system to repalce your spool or you install a clamp and assess the risk. beside its costly.

 

[amirkhizi]

Stainless steel is not recommend for Seawater.You can use Fiberglass Reinforced Pies(GRP or RTRP).As an inert material ,fibergalss composite pipes have excellent anticorrosive properties.Seawater, chemicals, soil and atmospheric environments typical in severe corrosion within a short period of time.I've been good experience with GRP lines for seawater service in South Pars Gas Field (Iran)

 

[ida]

As the above engineer say,316 is not suitable for chlorides sea water,it will made your pipe stress corrosion cracking. In our company we customerly use 402 or 921. 902 is also ok,and the price is lower than the others.

 

[mgp]

In the North Sea offshore industry it is quite common to use 6MO stainless steels for Seawater service (wet firewater systems and water injection). Sometimes also titanium is used.

Some (10 or more) years ago Cunifer piping (=Cupro-Nickel) was the standard material for seawater, but nobody uses this anymore due to fabrication, installation and mechanical strength problems I think.

GRP is also used for seawater but normally only for "non-critical" systems, i.e. systems that is not required to work in case of emergency.

Maybe though for a large diameter onshore header it it is acceptable, and cheaper to use one of the other suggestions above.

Try the site

http://www.steel.sandvik.com/

or

http://www.avestasheffield.com/steel_grades.asp

They have specs for SMO254


regards
Mogens

 

[mufasa1]

This will be 24" in diameter. Have you experienced 'Ductile Iron with coating'? Would that be acceptable for this service? What kind of coating is appropriate?

 

[saidsaz]

most common for seawater are ,,,FRP'S or C.S.cement lined

FRP'S potential problems are breakage...

cement lined c.s problems are when lining is gone...

a decision i beleive should be based on how good u will design and engineer any of the two options...

316 L ( known limit for the clorides part is 50 ppm ) ? seawater (thousands of chlorides ) ppms ?! no way !

cheers

 

[mufasa1]

For more responses to the same question, please see the following forum.

Materials Engineers Area - Corrosion engineering Forum

 

[thomasm]

I recommend GRP only for non-critical low risk installations. It easily breaks and is costly to repair. If you have a budget (or a long term installation) go for SS or epoxy coated ductile iron.

 

What are the methods availabe for cleaning the sea water intake pipe to get rid of any settlements clogging up the pipe or any living organisms that might gone into the pipe by chance?

 

[Frederico]

Try Zeron 100 Super Duplex Stainless steel. This should be suitable for your application. Available from Weir Materials.

 

[joeswoes]

For your valves, go to

http://www.pureflex.com

Series 800, composite butterfly valve.

 

[mufasa1]

George,
That is really an important issue if you are taking the water directly from the sea, lake etc. It is apparent that there will be clams and other settlements at the pipe intake. We think about using a self cleaning filter at the pipe intake. Lakos has such a filter up to 460m3/h for sea, lake and spring suctions. One idea was to keep the pipe out of the water at idle times with some kind of lever system which may not sound very practical..At the moment we do not have a clear solution. I will appreciate any idea on this matter..

 

[Statesman]

In the North Sea, Shell still use CuNi for Seawater systems. Another alternative is to use GRP

 

[kentchong]

Dear Mufasa,

Just for your reference, In our power plant practise, we use GRP pipe for seawater intake DN2500 (undersea & underground). For aboveground, we use A53-B with rubberlinned. Rubber linning is an good option for seawater.


Regards
Kent

 

[SNZ1]

In one of the ammenity centre pipe 316L is leaking which is given for firefighting purpose.Can somebody suggest some material or other way like filling that portion with fresh water. Underground pipe is of GRP.Firewater pump discharge is of Duplex Stainless steel
Thanks
SA

 

[tommyclose]

steel pipe cement mortar lined is suitable ,internationally accepted ,used and approved .....rgds TC