Practical consequences derived from the chemical investigation of the mechanism of fixation of CCA to the wood constituents are discussed. Among these, formulas for the calculation of the time of hexavalent chrome fixation are presented. Furthermore, three parameters are shown to be important to the long-term effectiveness of CCA-treated timber: (i) the temperature of treatment, (ii) the initial pH of the CCA solution and (iii) its concentration. Variation in the values of these three parameters cause drastic differences in the distribution between lignin and holocellulose of the preservative chemicals which will considerably affect the durability of CCA-treated timber. New, more economical and more effective application schedules and CCA formulations both in chemical composition and requiring lower retentions (softwoods) and imparting equal or superior durability to the treated timber can be devised from the results presented. From the results it appears that CCA formulations producing better soft-rot resistant hardwoods can be devised and the changes necessary to obtain this, are outlined.

Download document (600 kb)
free for the members of IRG. Available if purchased.

Purchase this document