Problem Solving Forum
May 1 - May 7, 2016
What criteria should an owner use to determine whether to specify full removal or spot- or zone-repair on a maintenance project?
Selected Answers
From
Warren Brand of Chicago Corrosion Group on
May 11, 2016:
Hire a seasoned, vendor-neutral corrosion professi ...read more
Hire a seasoned, vendor-neutral corrosion professional to assist in evaluation. There are an overwhelming number of variables to consider in terms of logistics, cost-benefit concerns, integrity of the existing coating system, service, time of year, aesthetics, surface prep limitations and requirements, type and age of coating system in place, etc. We worked on a multi-million dollar project where an existing coating system was in place. It was more than 20-years old. We were involved in a meeting among coating contractors, paint manufacturers, engineers, etc. Since each one of those vendors earned the fees by doing something, all of their recommendations were to remove the existing coating system. The data supported, however, that the existing system was performing exactly the way a new installation would perform, and we conducted empirical testing to conclusively determine that was the case. The client saved more than $1 million on that evaluation. Had they not had a technically competent, vendor-neutral entity in the mix, they would have removed a perfectly good coating system, run the risk of the new coating system not being as robust as the old one, or installed improperly, in which case they might have wasted a fortune.
From
MARIANA HUHULEA of Seaquest MPM on
May 10, 2016:
Decision-making criteria should be the existing co ...read more
Decision-making criteria should be the existing coating condition in key areas ( e.g., in ship repair, water ballast tanks and under water hull) of the project; and project's service lifetime scheduled by owners/operators after refurbishment. Budget should be adjusted accordingly and not vice versa, and, not the least, should take into account safety measures which, depending on circumstances, may add little extra to it.
From
Jose Avendano of KTA-Tator, Inc. on
May 7, 2016:
It depend of multiple factors: objectives of maint ...read more
It depend of multiple factors: objectives of maintenance project, paint system condition, rust grade, coating thickness, etc. Thus, it's necessary to carry out a coating assessment in order to determine the corrective actions. For example, a spot repair is an option when repairs are hidden or in low visibility areas, structures are small, not requiring extensive scaffolding or hard-to-access areas, corrosion and degradation are limited to isolated areas and relative small sections, which amount to less than 1% of total area. A full removal is an option when the paint condition is poor or bad and when funds are available. Consult SSPC-PA Guide 4, "Guide to Maintenance Repainting with Oil Base or Alkyd Painting Systems;" SSPC-PA Guide 5, "Guide to Maintenance Painting Programs;" and SSPC-TU 3, "Overcoating."