New Paint Preservation Technologies for Offshore & Marine Equipment
by Jim Britton (1998) from NAVY Conference
Offshore and marine operators, without exception, spend the largest part of their corrosion budgets on paint maintenance. The failure of a “well applied” paint system can be traced to a few basic failure mechanisms. Some of these mechanisms are addressed in this paper. If the solutions presented are applied, then paint systems will last much longer, and maintenance budgets can be diverted to other areas.
The systems presented are no substitute for poor, out of specification, surface preparation or application. The writer therefore, would always recommend using qualified paint inspectors during the initial coating of any marine structure. The mechanisms presented do not represent a complete list, but do reflect some of the more common problems.
Pipe Flange Corrosion
Pipe flanges are a built-in failure point on any piping system exposed to a marine atmosphere. From day one, when the flange is initially assembled, coatings on the inside hidden surfaces of the flange are damaged by the fasteners which hold the flange together. Once a flange is assembled, there is no way to paint these inner surfaces, but salt water and free oxygen intrusion, ensure that corrosion is free to occur. The result is unsightly corrosion products leaching from the flange gap and dripping onto other coated surfaces [Fig. 1]. The ultimate result could be the failure of the joint from either fastener corrosion [Fig. 2], or gasket seal corrosion.