Performance requirements for a two-component epoxy primer coating and moisture-cured polyurethane coating system are the subject of two new standards from SSPC: The Society for Protective Coatings.
Epoxy Primer Coating Standard
SSPC Paint Specification No. 42, Epoxy Polyamide/Polyamidoamine Primer, Performance-Based, was developed by SSPC’s Epoxy Coatings Committee (C.1.3.C), chaired by Greg Girard of The Sherwin-Williams Company.
This is a new performance-based standard for a two-component epoxy coating for use as a primer on blast-cleaned steel. It includes requirements for flexibility, direct impact resistance, chemical resistance, and humidity resistance as well as for rusting, blistering and scribe undercutting after exposure in a cyclic salt fog/UV exposure test cabinet.
The purpose of the standard is to give the specifier evaluation criteria that can be used to define requirements of an epoxy primer coating submitted for inclusion in the production specification and/or owner’s QPL.
The standard is expected to be most useful to owners and specifiers who require a high-performance epoxy primer coating.
Polyurethane Coating System Standard
Coating System Standard SSPC-PS 28.02, Three-Coat Moisture-Cured Polyurethane Coating System, Performance Based, was developed by the Polyurethane Coatings Committee (C.1.3.D), chaired by former SSPC president Michael J. Masciale.
This standard contains performance requirements for a moisture-cured polyurethane coating system for use on steel substrates comprised of a zinc-rich moisture-cured polyurethane primer meeting performance requirements of SSPC-Paint 40; a moisture-cured polyurethane intermediate coat meeting requirements of SSPC-Paint 41; and a moisture-cured aliphatic polyurea topcoat meeting requirements of SSPC Paint 38.
The performance requirements for the coating system include minimum adhesion criteria for the primer to the substrate and for the intermediate and topcoat adhesion to the primer, as well as minimum requirements for rust, blister and scribe evaluation of the three-coat system.
The standard also contains requirements for three performance levels based on the color and gloss retention of the topcoat. For example, a specifier who desired maximum gloss and color retention for a three-coat moisture cured polyurethane coating system would require conformance to PS 28.02 Level 3 requirements.
The coating system utilizes three single-package moisture-cure urethane coatings that are being used as a system in the field, especially in high-humidity environments, and can be used in cool-weather applications. This standard may be used to define requirements of a coating system submitted for inclusion in project specifications and/or Qualified Product Lists.
Industry segments likely to use this standard include highways and bridges (rapid recoat times, high humidity environments); water-treatment facilities (high humidity environments); and general industrial (refineries, utilities and various high humidity applications).