Urethane Top Coat on CS Surfaces 1

[1969grad]

I am working on standardizing some paint specs and wonder about the advisibility of a urethane top coat. A local paint vendor states that it is not economically feasible as the urethane coat wears off after a few years and serves only to hold the paint color through the first years.

The urethane is over an epoxy primer and second coat. An alkyd system is used for interior locations and does not require the urethane top coat.

My applications are onshore, aboveground, exterior carbon steel piping operating at less than 200 F.

So is the urethane top coat a waste of money?

 

[kenvlach]

Get another paint vendor. Polyurethane topcoat is standard procedure for protecting epoxy primer from UV of sunlight.
See MIL specs. and US Army Corp of Engineers Manuals.

 

[SJones]

Take a look at ISO 12944, particularly part 5.

Steve Jones
Materials & Corrosion Engineer

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