Aliphatic polyurethane water based 13 epoxy organic

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Aliphatic Polyurethane (Water Based) 13 Epoxy Organic Zinc-Rich Acrylic Waterborne** Acrylic Waterborne 14 Thermal Sprayed Zinc Acrylic Waterborne 15 Thermal Sprayed Zinc 16 Low Viscosity, 100% Solids, Epoxy Penetrating Sealer or Polyurethane Penetrating Sealer Epoxy Mastic or Polyurethane Acrylic Epoxy or Polyurethane Notes * Oil and Alkyd paints include alternate inhibitive pigments to lead such as zinc oxide, barium metaborate, zinc hydroxy phosphate, calcium boro silicate, calcium sulphanate and zinc molybdate, which have been tested and are acceptable alternates. ** Acrylic Waterborne paints are available with numerous resin systems and pigmentations. *** Polyurethane Aluminum Primer and Polyurethane Micaceous Iron Oxide can be used as a primer on bare steel, or as a penetrating sealer on existing coatings. They should be specifically formulated for whichever use is intended. Table 1 Paint Systems
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SYSTEMS PAGE 38 It is reasonable to conclude that painting is not mandatory for interior steel framing in low humidity environments, provided the structure remains water tight. The question then must be asked, why paint interior steel at all ? If the steel of a building under construction is exposed to the elements for a normal period of time prior to enclosure, the minimal corrosion which occurs on the unpainted steel would not be considered to be structurally detrimental. The issue then becomes a matter of aesthetics. The appearance of "raw" steel may not be desirable. Customers and building owners usually prefer the appearance of a painted surface to a rusty surface on exposed steel framing. Table 2a Paint Systems in Table 1 Applicable to Maintenance Painting Involving Spot Repairs and Overcoating EXISTING PAINT SYSTEM HIGHLY CORROSIVE* ENVIRONMENT MILDLY CORROSIVE ENVIRONMENT Zinc-Rich 3,4,5,7,10 11,12,13,16 3,4,5,7,9,10 11,12,13,16 Oil/Alkyd 6,7,8,9,10 16 6,7,8,9,10 16 Vinyl and Chlorinated Rubber 6,9,10 16 (Polyurethane Penetrating Sealer) 6,9,10 16 (Polyurethane Penetrating Sealer) Epoxy** or Polyurethane** 5,6,7,10 16 5,6,7,10 16 Table 2b Paint Systems in Table 1 Applicable to New Construction or Maintenance Painting Where Existing Paints are Completely Removed HIGHLY CORROSIVE* ENVIRONMENT MILDLY CORROSIVE ENVIRONMENT 1,2,3,4,10 11,13,14,15 1,2,3,4,5,6,7,10 11,12,13,14,15,16 Paint systems reference numbers (see Table 1) shown in bold text are considered “Newer Technology” for either coating unpainted steels or topcoatings over existing paints. * A highly corrosive environment may be a “macro” environment where high ambient chloride levels exist such as immediately over salt water, or a “micro” environment where only a portion of a structure is exposed to such things as manufacturing process chemicals or humidity or both. All other environments are considered at least “mildly” corrosive. ** Roughening of surface may be necessary
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PAGE 39 SYSTEMS There are, however, disadvantages to painting interior steel that is not exposed to view. One disadvantage is the cost. Shop painting can be expensive, particularly if the steel fabrication shop does not have the appropriate painting facilities. For example, not including surface preparation by blasting or other means, a single coat of
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  • Fall '19
  • Structural steel

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