Problem Solving Forum
July 25 - July 31, 2011
What are the options for shop-applied systems (surface preparation and coating type) to protect the interiors and exteriors of new saltwater storage tanks and associated steelwork that will be exposed to seawater, and that will allow for easy touchup and maintenance once the structures are erected?
Selected Answers
From
Lee Edelman of Independant on
July 29, 2011:
Assumption - In logic an ...read more
Assumption - In logic an assumption is a proposition that is taken for granted, as if it were true based upon presupposition without preponderance of the facts. ...
From
jesse chasteen of schriener construction on
July 28, 2011:
And who has the most seaw ...read more
And who has the most seawater tanks...the US Navy. Use the surface prep spec for seawater ballast and paint the outside anything but gray.
From
Larry Muzia of Exceletech LLC on
July 28, 2011:
For the exterior system, ...read more
For the exterior system, I would recommend an SSPC-SP 10 with 2-mil anchor and 3-5 mils dft of an inorganic zinc. After proper cure, I would apply a 5-mil epoxy followed by 3 mils of a good quality aliphatic urethane. On the interior there are several systems that would perform. One could be SSPC-SP 5 blast with a 3-mil anchor profile, followed by a 2-coat epoxy system to achieve 30-40 mils dft. A holiday test would be necessary to insure a pinhole-free film. A 100% SBV epoxy or a glass flake polyester applied at a similiar dft would also be a good choice.
From
Lee Edelman of Independant on
July 27, 2011: There are several coat ...read more
There are several coating systems that could be used for this application. The selection will depend on how aggressive is the environment, temperatures and chemical exposure. For the interior surfaces, use an SSPC-SP 5 abrasive blast with a proper anchor profile. In some cases, such as sea water strainers, use anodes properly placed and a compatible coating or lining. All welds and edges should be stripe-coated. After proper cure time, which can be done faster by force curing, a holiday test should be done to insure proper film coverage. Exterior surfaces can be done using the same methods, excluding the anodes. In most cases, an easy touch up is hard to achieve for interior coatings and linings due to the process of opening the vessel, inspection, assessment, and conformance with reuirements of confined space entry. Exterior surfaces will allow for an easier touch up and maintenance due to access.
From
Ron Lanter of Protec on
July 26, 2011:
Saltwater storage tank? I ...read more
Saltwater storage tank? I mostly work offshore, but I don't think I've ever seen one of those. Why would you store salt water? Anyway, if you did, I would coat my tank inside and out with 300 M coal tar epoxy, and if I had to make any repairs, I could do that by power tool cleaning and brush coating more coal tar if the repair was a minor one; otherwise, you could drain the tank and sweep with #4 sand and re-coat with 300 M.
From
Venkatasubramanian Chandramouly of Berger Paints Emirates Limited on
July 25, 2011:
The surface prepration no ...read more
The surface prepration no doubt has to be blast clean to Sa 2.5 or Sa 3.0. In terms of paint applicaton, there are a wide variety of paints available in the market from various manufacturers in tanklining sections. Depending upon the temperature of the water and service life requirements, various coatings (BPA epoxy type, Phenolic epoxy type) can be selected. They can also be cured under water, and even coatings that can be applied (for maintenance) under water (by hand) are available in the market.