have been applied to many pile structures since 1955 and are proving 

 to be more durable than ordinary coal tars. Many other non-metallic 

 coatings such as vinyls, rubbers, phenolics, sarans, mica-filled as- 

 phalt emulsions, epoxies , urethanes, polyester-glass flake, and furan 

 are being tested for service on steel piling by the U. S. Naval Civil 

 Engineering Laboratory, the National Bureau of Standards and the Coastal 

 Engineering Research Center. Information on non-metallic coatings from 

 tests in progress or completed are presented in paragraphs to follow. 



(l) Bituminus . A coal-tar coating cold-applied to steel 

 piling for a test in seawater was in poor condition after 2 1/2 years 

 in the zones that included the tide and sand abrasion. However, it was 

 still effectively protecting the steel in the atmospheric and imbedded 

 zone. The evaluation ratings given this coating at various test inter- 

 vals up to 2 1/2 years are shown in Tables II a and II b. 



Panels coated with a system consisting of a coal-tar primer, a 

 coal-tar enamel and a natural resin anti-fouling topcoat were reported 

 to be in "remarkably good" condition after 6 years immersion in tropical 

 seawater. See Table IV. These coatings were applied very thick (70-100 

 mils). The same coating systems were considered inadequate for 6 years 

 of exposure in seawater at mean tide level (Alexander, Forgeson, and 

 Southwell, 1958). 



Asphalt and coal-tar coatings on steel were tested in seawater at 

 a harbor and a surf site at Port Hueneme , California. After exposures 

 ranging up to 6 years, these coatings were found to be quite good for 

 marine atmospheric exposure but did not show long-term durability in 

 the tidal and submerged zones. One of the primary causes of failure was 

 damage to the coatings by fouling organisms. Substantiating this theory 

 is the fact that anti-fouling coal-tar coatings gave longer protection 

 than other types in these tests (Alumbaugh and Brouillette, I966). See 

 Figures 11a and 12. 



(2) Vinyl . Vinyl coatings are one of the more successful 

 coatings for protecting steel in seawater. Of 83 coating systems tested 

 on steel panels exposed to seawater in the tide zone for 6 years, 3 vinyl 

 systems including a topcoat of anti-fouling paint were among the five 

 best coating systems (Alexander, Forgeson, and Southwell, 1958). These 

 coatings are included in Table V which lists the 5 coatings considered 

 satisfactory for the mean tide zone after 3 years exposure. The vinyl 

 coatings, however, were not considered to adequately protect the metal 

 panels after 6 years immersion in seawater (see Table IV). 



Vinyl coatings were included in coatings tested on piling driven in 

 the surf zone at Port Hueneme, California (Alumbaugh, I962). The ratings 

 of the vinyl coatings (vinyl mastic and aluminum vinyl) after 2 1/2 years 

 of exposure are shown in Tables II a and II b. These coatings were also 

 tested on steel sheet piling and H piling driven at Cabras Island (off 

 Guam) in the Marianas. The coating evaluation results of this test are 

 given in Table VII. 



28 



