Coal tar enamel coating as per AWWA C203

[onrush]

Dear members,

A project document requires coal tar enamel coating as per AWWA C203 for underground water piping.

However this is the first time for me to use coal tar enamel coating for underground water piping.

My question is,

What is the benefit of coal tar enamel coating instead of PE or PP coating for underground piping?

Is coal tar enamel coating cheaper than PE or PP coating?
If so, approximately how % is it cheaper?

Thanks...........

 

[SJones]

Coal tar enamel is an excellent pipe coating it's just not the most health and safety orientated one! If you can get a change, at least try for asphalt enamel to EN 10300 (DNV RP-F106 may be a little over the top for your water line) which will perform just as well and may save the health of an application worker somewhere!

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

 

[rconner]

As Mr. Jones has indicated (while there has been past use of C203 coatings, and old specifications no doubt exist) most modern steel water pipe is now provided with other coating systems and there may now be little if any use of the C203 systems. While you do not note the size nor length of the pipeline you are talking about, I believe a great many larger/longer steel water pipelines are provided with modern versions of "polyethylene tape wrap" systems per AWWA C214 (e.g. as you can see described on page 13 on at

http://www.acipco.com/aswp/pdfs/ASWP1-Introduction.pdf),

although I think at least some larger steel water pipe are supplied instead with polyurethane coatings per AWWA C222 and other coating systems.

 

[cvg]

while asphalt enamel may be safer to apply, it is not necessarily any safer to produce as the asphalt tar and vehicle are petroleum distillates refined in much the same way as coal tar. It requires petroleum based vehicle to apply vs heat application of coal tar. Either way, noxious fumes are released, perhaps for a longer period of time with the asphalt enamel. I'm not sure I would recommend PE or PP wrapping alone without some sort of enamel coating.

http://www.easterntarcoatings.com/CTEApplication.htm

http://www.lonestarspecialties.net/coaltar.html

 

[brimmer]

Sounds like a "project document" that has not been updated recently, I have not seen coal tar or aspshalt coating applied for years now. Remember PE or PP coating will shield cathodic protection. Might be over kill, but I would go with an epoxy coating, though I don't know your local conditions/environment etc...

 

[SJones]

Asphalt enamel was the pipe coating of choice for the UK North Sea where it is still performing admirably. The Middle East is still happy to slap coal tar enamel on a number of their offshore pipelines.

This is a good thread because it now draws attention to issues involved with pipe coating selection: HSE, cost, reliability, durability, interaction with cathodic protection and so on and so on.

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

 

[mak72]

In my opinion Serviwrap Tape and Bitutape primer can be used.