Sawn timber of fir (Abies alba Mill.) - Treatability and usability for the Hazard Classes 3 and 4
E Graf, T Bör
Within a national research project, tests on the treatability on sawn timber of fir (Abies alba Mill.) in oscillation pressure, vacuum pressure and double-vacuum processes have been worked out with 95 trunks taken from 3 different altitude levels (up to a height of 590 metres, 600 to 990 metres and over 1000 metres) and from 4 different regions of Switzerland. As the treatability of round wood can be compared with that of spruce (Picea abies L.), the sawn timber shows a considerably higher retention and penetration of the preservative. According to the standard EN 350.2 this wood can be classified into treatability class 2. With a vacuum pressure process a much better quality can be reached than with an oscillation pressure treatment. The treatability can be influenced by the origin of growth, as far as wet heart appears increasingly on a fir location; lumber with wet heart has a four times higher retention. The altitude of growth had no significant influence on the impregnation quality. The good retention and penetration of the preservative makes these wood species suitable for weather exposed outside constructions of solid wood or glued laminated timbers (for example bridges, acoustic and face protection walls, fences and toys). As the heartwood of fir is impregnated too, an adequate or even longer durability than with Scots pine (Pinus ssp.).can be obtained for treated construction wood.