Zinc-rich primers, with zinc dust loadings of 80-85% by weight in the dry film, are often the preferred primer during new construction of assets placed in environments with high atmospheric corrosivity. Coating standards such as SSPC-Paint 20 and ISO 12944 demand that zinc-rich primers contain at least 65% and 80% zinc dust by weight in the final dry film, respectively. Traditional zinc rich primers need this high zinc loading to achieve galvanic protection of steel. New technology allows us to develop zinc primers with a lower content of zinc and/or different zinc morphology than dust to provide similar or better corrosion protection to the steel.
CUI (corrosion under insulation) is a pervasive, difficult and high-liability issue for petrochemical, power, shipping, and other industries. Situational variations (meteorological, geographical, seasonal, etc.) can confound conventionally specified surface preparation attempts to achieve perfect or near-perfect metal hygiene, thus reducing expected coating life by 30 to 75 percent. Because conventional surface preparation processes have historically been unable to adequately relieve microcontamination of metal surfaces, organizations have settled for an uneasy balance between economic and physical feasibilities that exclude the possibility of achieving ideal surface preparation outcomes and rely more heavily upon barrier coatings to supply needed corrosion control.
The author will present on the various generic coatings technologies available for lining concrete and discuss the advantages and disadvantages of each one. Discussion will include epoxy, polyurethane and polyurea technologies. The goal of the presentation will be to provide some guidance to the attendees on when is the right application to select each technology as part of a specification.