Steel Pipe Cement Mortar Vs Epoxy Lining 3

[BRIS]

Large diameter steel water pipe to convey raw water is specified to have cement mortar lining. Contractor wants to Use Solvent Free Epoxy lining instead. Client requires assurance that solvent free epoxy will give 50 year design life.

I am looking for a source of comparisons advantages, disadvantages etc.?

 

[SteveWag]

I would be inclined to stay with cement lined pipe. In addition to providing a self-healing protective barrier, the cement prevents the build up of tuberculation. I have removed 3-4 inches of tuberculation from 100 year old cast iron pipe and found the cast iron to be undamaged. While tuberculation grows on unlined pipe over the years, I have found 50 year old cement lined pipe to be free of any sign of tuberculation.

Steve Wagner

 

[ApC2Kp]

BRIS,

There is not 50 years of service history to back up the use of epoxy coatings. A couple of rubber lined and epoxy lined installations have been problematic with reminders of the need for proven bonding and curing processes to ensure good adhesion. Otherwise there will soon or eventually be problems from outgassing and de-lamination. Good results and performance of epoxy fiberglass pipe does not translate to epoxy lining performance in steel pipe.

You probably have used or seen large diameter pipe products of Northwest Pipe Company. Almost all of their production receives lining and coating. Their website describes some of the options for linings and coatings. They probably could provide additional data for consideration of lining materials. The cement lining appears to be most commonly used for raw or potable waters, as mentioned by SteveWag. The epoxy or other linings seem to have benefits for corrosive / aggressive service. I would consider the epoxy linings to be useful for re-hab and protection of sewer pipe, like the products of the Insituform Co.

http://www.nwpipe.com/

http://www.nwpipe.com/technical_resources_manual.html

http://www.nwpipe.com/technical_resources_papers.html

http://www.insituform.com/

 

[BRIS]

Thanks for the response 0- The arguments put forward by the contractor for epoxy linining are all to do with ease of handling which are benefits to the contractor not the client. Pipe diameter is 1600 mm. My preference is also CML but my case is not strong enough !

 

[robsalv]

If potable water, then the epoxy lining may fall over due to chemical leaching.

- - - - - - - - - - - - - - -
"Life! No one get's out of it alive."
"The trick is to grow up without growing old..."

 

[rconner]

I believe cement mortar linings for water pipelines have a history of general efficacy since their first use (I suspect to protect sheet-iron or wrought iron pipes) at least a century and a half ago (probably much longer than that if you count all forms of concrete pipes). Many utilities probably wish that they would have went to them sooner, to minimize internal tuberculation and maintain good flow coefficients. Various forms of epoxies have been employed for various pipes in of course much more recent decades. I am aware that the AWWA Research Foundation (AWWARF) conducted a study of internal corrosion of water pipes twenty years ago or so, and published a voluminous report of that research that included at least a comparison of in-situ cement mortar lining vs the epoxies of the day. I have also seen more recent reports by others, generally promising great performance and long life of the epoxies they promote, and maybe even some presumeably backed by some "accelerated" testing they say predict that long life.

In addition to what others have already said, I would only add that AWWA M11 notes that cement mortar lining provides some dependable extra ring stiffness to some otherwise quite flexible thicknesses sometimes used for steel pipes, whereas epoxy would not. If you decide to go with epoxy and a final service of the water is potable, you might want to check also (further to robsalv's post) that the material is certified for that use at the temperatures that will be involved in the project [I believe plastics and polymeric materials in general could be more subject to leaching behaviors at higher than normal/room testing temperatures].

 

[robsalv]

Thanks rconner for clarifying my fairly ambiguous post! I must've been having an off day. Cheers.

- - - - - - - - - - - - - - -
"Life! No one get's out of it alive."
"The trick is to grow up without growing old..."

 

[BRIS]

Thanks for the responses. Since starting this thread I have been researching the issue. AWWA have published a report 'Service life Analysis of water Main Epoxy Lining'.

My general conclusions are that epoxy lining will give a service life of 40 to 50 years before the onset of corrosion. Cement Mortar Lining in hard non aggressive water will give 70 years. In the UK where a lot of the conveyed water is soft epoxy lining has been used extensively but preference is now given to polyurethane linings which are more flexible and easier to apply.

Manufacturers are working at improving the flexibility and ease of application of 100 solids (solvent free) epoxy. Polyurethane may however be a better choice?

In the US epoxy is being used extensively and successfully to reline existing pipes to extend their service life by up to 40-50 years.

I still have not reached firm conclusions.

 

[rconner]

Thanks for letting us know of your findings. Of course some areas in the USA have also had quite soft, aggressive, and/or tuberculating waters. As can be noted by the publication at

http://www.dipra.org/pdf/cementMortarLinings.pdf,

I believe this was in fact the specific reason that factory cement mortar linings were developed for and applied to 8" cast iron pipes in 1922 (a water/area with known quite tuberculating characteristics and negative Langelier etc. index). I am aware that the Hazen-Williams flow coefficient of this and other cement-lined pipelines have been periodically measured by CIPRA/DIPRA over the years (working closely of course with interested utilities involved), and in 1999 (of course immediately before entry into the 21st century) the measured coefficient of this very first cementlined CI pipeline was C=130 at that time). I believe this pipeline is incidentally still in service, now 86 years of age. I do not have similarly specific information concerning cement-lined steel pipelines, but I agree the performance in general of these is likely also quite impressive.

 

[ApC2Kp]

bris,

The life of cement mortar linings or epoxy linings could be impacted by changes taking place in the chemistry for purifying potable water. There was a recent article in the Flow Control magazine that described some testing of elastomers for effects of chloramination - the use of reduced levels of chlorine with addition of ammonia for longer residual effects.

http://www.flowcontrolnetwork.com/issuearticle.asp?ArticleID=212

There might be liittle effect on the cement lining, or the epoxy lining might result in longer life, if the cement lining is deteriorated by chloramination. There certainly appears to be be definite effect on the elastomers in typical water piping system.

This would not effect a raw water system, if that is what you have to consider.

 

[rconner]

ApC2Kp, while I guess all of us should try to envision the future and change as much as we can in our work and home lives (and this is even kind of fun to do!), I‘m not sure at least related to the materials discussed of the specific examples of chloramination you’ve chosen. While there is indeed likely increasing use of chloramines over other chlorine forms for various reasons, actually it is not really new technology. In this regard, you may be interested in the EPA fact sheet at

http://www.epa.gov/region09/water/chloramine.html.

As far as cement-lining and chloramines for disinfection, I believe one of the very earliest utilities to use chloramines was reportedly Boston, MA in 1932. I believe Boston also is a quite prolific contemporary user of cement mortar linings, and incidentally just a very few years ago chose that very technology to rehabilitate with minimal disruption and for even longer life substantial sections of some major, unlined iron mains that were at the time in excess of 100 years old. As far as concerns of chloramination, I have incidentally also noticed that there have apparently been some concerns of chloramination that may be sort of opposite what you expressed (see effects on at least some sort of epoxy linings for at least small plumbing materials at

http://waternet.com/article.asp?IndexID=6636816

). I do not know if that “epoxy-lined” pipe tested is anything like what Bris is looking at.
While some rubber and other polymeric items have indeed likely been affected by disinfection practices (examples are thin plumbing items with which we are all likely some familiar, or have even “put our hands on”), it has been reported e.g. in Bonds R.W. (2004), Effect of Chloramines on Ductile-Iron Pipe Gaskets of Various Elastomer Compounds, Journal AWWA, vol. 96, 4, 153-160 that the configuration and quality of standardized, modern pipe gaskets per ANSI/AWWA Standard C111/A21.11 used with at least ductile iron pipe in the USA are reportedly quite unlike those items.

 

[pkruchoski]

Bris,
I work for a polyurethane manufacturer who specializes in lining pipe spools. Our urethanes have been submerged for over 25 years with no chemical or bond break down. Our materials are ment for abrasive materials, not just water, so there may be a cheaper solution than ours. You will be looking for a MDI-PTMG (diisocyanate system) polyether polyurethane. DuPont/BASF/Dow may be good places to start.

check out our website if you have a chance:

http://www.irproducts.com

thanks Pete