Treatability of Lodgepole Pine Lumber with ACA and CCA

Kiln-dried, incised lodgepole pine lumber was pressure treated with chromated copper arsenate (CCA) and ammoniacal copper arsenate (ACA). We studied the effects of varying 1) the preservative type (ACA and CCA); 2) the preservative solution temperature (20? and 60?C); 3) the treating pressure (850 and 1050 kPa); and 4) the density of the incising pattern (single and double), on chemical retention and penetration. Generally the heartwood was resistant to impregnation by both ACA and CCA. The average minimum depth of the preservative penetration from the incised surface of the boards was unaffected by variation in temperature or pressure, but was greater in doubly incised boards (3.4 mm CCA; 4.5 mm ACA) than in singly incised boards (2.4 mm CCA; 2.9 mm ACA). From the average “lateral” penetration of the preservative into the wood surrounding the incisions, it was concluded that the lateral spacing of the incisions should be reduced to 3.5 mm to ensure an acceptable penetration. It was also recommended that the incision depth be increased to 10 mm and that a staggered rather than a diamond incising pattern should be used. There was no practical difference between the retentions of either ACA or CCA and, as expected, increasing the density of incisions increased the chemical retention.

You must be logged in to download any documents. Please login (login accounts are free) or learn how to Become a Member