Different coating for buried pipes

[mariocalvo]

Dear all,

We have a flange which shall be coated with polypropylene coating system in a piping buried system. Our supplier offer us to coat with polyurethane (800 microns).

I would like to know if this is acceptable.

Thanks in advance

 

[rodneybennet]

Polyurethane has better adhesion properties. On the other hand, polypropylene is generally much more chemically stable in environments containing moisture (but is not so good in adhesion, this may give rise to osmotic driven blister formation: this may be solved by a sufficient layer thickness of polypropylene).

For more quantitative information (on chemical degradation of polyurethane, diffusion rates, etc.) and material suggestions you may try to post this issue also at:

http://www.composite-agency.com/materials-forum.htm

Regards,
Rodney

 

[SJones]

It can be acceptable if your supplier can demonstrate to you that the coating, when applied correctly, will have satisfactory performance. One way of doing that is to provide data from a qualification test programme. An example of a qualification test programme (for FBE) is given at:

http://www.kta.com/knowledge/PACE2006/FusionBondedEpoxy.pdf

It shows the sort of data that one looks for when assessing coatings for protection of buried pipe.

Steve Jones
Materials & Corrosion Engineer

http://www.pdo.co.om/pdoweb/

 

[mariocalvo]

Thanks for this important information