(6) Coating Coverage . The volume qf a 3.785 liter (one gallon) 

 container of paint is 0.003 8 cubic meter (231 cubic inches), according to 

 the U.S. Bureau of Standards. If the paint is 50 percent solvent which 

 volatilizes as the coating cures, the effective remaining paint for surface 

 coverage (paint film) is 50 percent or 0.001 9 cubic meter (115.5 cubic 

 inches). Some paint products contain more than 50 percent solvent, others 

 contain less, and there are a few that contain no solvent; i.e., they are 

 essentially 10Q percent solids. If 0.003 8 cubic meter of nonvolatile 

 material is spread on a surface as a coating film 25.4 micrometers (1 mil) 

 thick, it will cover 150. square meters (I 604 square feet). 



If the coating contains 50 percent volatile solvent (by volume), its 

 surface-covering capabilities are reduced 50 percent. At a 25.4-micrometer 

 dry film coating thickness, it will cover 75 square meters (802 square 

 feet). The coating as applied will be "wet," containing 50 percent solvent 

 (by volume). It will be 50.8 micrometers (2 mils) thick. As the solvent 

 evaporates its thickness will decrease. Where all the solvent has volatilized 

 (vaporized) the dry film thickness will be 25.4 micrometers. As mentioned 

 earlier, coating thickness will vary from 38 to 76 micrometers for alkyds and 

 up to 250 to 760 micrometers for heavy coal-tar coatings or mastics. 



f . Inspection . Coating inspection work starts with the surface 

 preparation. Details relating the degree of surface cleanliness to the 

 surface preparation specified are found in the Steel Structures Painting 

 and will not be discussed here. Coating application must be in strict 

 accordance with the coating manufacturers' recommendations. Inspection of 

 coating application, including touchup, repair, and maintenance work, will 

 be centered around compliance with these recommendations. 



Inspection will include items such as making sure that coatings with 

 dense pigments (such as zinc-rich coatings and red lead primers) are 

 continuously stirred during application, measuring and recording both the 

 air and the surface temperature and the humidity, determining the shelf 

 life of the coating, and using it within its shelf life, and becoming 

 thoroughly familiar with the coating products being used and the manu- 

 facturers application procedures. 



g. Coating Repair and Maintenance . During construction there will be 

 damage to the coating system. Also, after erection, welding areas (weld 

 lanes) will require surface preparation and coating. This section will 

 consider touchup and repair of these areas before going into maintenance 

 coating work. Priming is frequently done before erection. After erection 

 the weld lanes are cleaned and primed and the coated areas damaged during 

 erection are repaired. 



Inorganic zinc is also frequently used as a preconstruction primer 

 because of its toughness (resistance to damage) and its excellent corrosion 

 resistance. Organic zinc-rich primers (such as epoxy zinc riches) are 

 often used for weld lanes and repair work after erection. The organic 

 zinc-rich coatings have better adhesion qualities and are "more tolerant" 

 of imperfect surface preparation than the inorganic zinc coatings. Other 

 primers utilized for weld lane touchup work include primers from all the 

 generic coating classes, including alkyds, vinyls, epoxies, universal (a 

 primer which can be topcoated with any topcoat without lifting, usually 

 containing a phenolic resin) . 



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