other chemicals, frequently including a chromium compound. Chromated zinc 

 chloride (CZC), which is composed of a mixture of zinc chloride and sodium 

 dichromate, has come into wide use in recent years. The preservative is 

 now much more extensively used than straight zinc chloride, which was 

 formerly the most widely used waterborne salt. A less widely used compound, 

 Fluoro-chrome-arsenate-phenol (FCAP) , is one of the preservatives listed in 

 the current standards and government specifications. 



Arsenic compounds have been used as preservatives for many years. They 

 are important ingredients of a number of proprietary preservatives, some of 

 which have demonstrated high effectiveness and are extensively used. Three 

 effective compounds commonly used are chromated copper arsenate (CCA) , acid 

 copper chromate (ACC) , and ammoniacal copper arsenate (ACA) . Three types of 

 CCA are specified in Interim Federal Specification (U.S. Department of Agri- 

 culture, 1974). The type is chosen according to availability and economics. 



Copper sulfate, although extensively used in Europe for many years and 

 demonstrated to be moderately effective in retarding decay, has found 

 little use for wood preservation in the United States except in certain 

 proprietary preservatives, in which it is combined with other chemicals. 

 Several of these preservatives are of high effectiveness and extensively 

 used. Copper sulfate is corrosive to iron and steel and, therefore, cannot 

 be used alone in ordinary treating equipment. 



(4) Proprietary Preservatives . Various patented or proprietary pre- 

 servatives are sold under trade names for pressure treatment. For the most 

 part they are composed of various waterborne salts and are injected in water 

 solutions. Others employ a volatile solvent to carry the toxic substance 

 into the wood. Some of the waterborne preservatives contain chemicals that 

 are intended to react after injection into the wood and to form substances 

 that are of low solubility and resistant to leaching. 



Wolman salts is one of several proprietary names for a waterborne salt, 

 chromated copper arsenate (CCA), also known as "green-salt." Chemonite is 

 another proprietary name for ammoniacal copper arsenate (ACA) . Other 

 proprietary names for preservatives can be found in the American Wood 

 Preservers Association Standard (AWPA) M9. It lists a number of proprietary 

 names for each of the standard preservatives. 



8. Specific Applications for Treated Wood . 



a. General . Tables 33 and 34 indicate the amount of preservative to be 

 retained in various wood forms using approved practices for preservative 

 treatment with creosote and solutions containing creosote, pentachlorophenol, 

 and waterborne preservatives. The net retentions in the tables are minimum 

 penetration requirements. Higher net retentions may be needed for severe 

 use conditions and should be specified when applicable. Data in the tables 

 are taken from Federal Specification TT-W-571J. 



Coal-tar creosote, creosote-coal tar solution, creosote-petroleum solu- 

 tion, and pentachlorophenol in heavy petroleum solvent and the four water- 

 borne preservatives, ACA, and CCA Types A, B, and C are ordinarily to be 



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