Rates of fixation in chromated copper arsenate (CCA-C) treated red pine (Pinus resinosa Ait.) and southern pine (Pinus spp) sapwood specimens using retention of 1.5, 2.0, 6.4 kg·m?3 are compared at temperature (T...Rates of fixation in chromated copper arsenate (CCA-C) treated red pine (Pinus resinosa Ait.) and southern pine (Pinus spp) sapwood specimens using retention of 1.5, 2.0, 6.4 kg·m?3 are compared at temperature (T) ranging from 70°C to 50°C and 5 different relative humidity (RH) conditions. The samples were investigated using the expressate method to follow chromium fixation. Red pine fixes faster than southern pine under all 11 post treatment schedules. The fixation rates for both species are not significantly different while the blocks were fixed under 6 fixation/drying schedules that differed only in the order of T/RH conditions applied. The rate of fixation of all samples in any fixation stage were reduced when the blocks were fixed under lower humidity conditions in spite of no change in chamber temperature. Some of this influence can be attributed to the effect of humidity on heat transfer into the wood and cooling of the wood surface.展开更多
The effects of fixation drying conditions on fixation rates and chemical leachab ility were investigated with CCA-C treated red pine (Pinus koraiensis Sieb. )and southern pine specimens at a retention of 6 4 kg·...The effects of fixation drying conditions on fixation rates and chemical leachab ility were investigated with CCA-C treated red pine (Pinus koraiensis Sieb. )and southern pine specimens at a retention of 6 4 kg·m -3 , and under 11 post-treatment schedules ra ng ing from 50～70℃ and 5 different relative humidity conditions. These samples w e re monitored by expressing residual liquid and analyzing it for hexavatent chrom ium content. Samples were subjected to AWPA E11-97 (AWPA 1997) standard leachi n g tests after fixation. Generally, red pine fixed slightly faster than southern pine for most fixation conditions. High temperature, high humidity, fixation co nditions during the fixation/drying schedules resulted in faster fixation and lo wer leaching of chromium and arsenic elements compared to low humidity condition s. Copper leaching showed no significant difference under 11 fixation /drying co nditions for both species. All of the CCA components were leached significantly more in red pine than southern pine. Further work is needed to examine the effec ts of different fixation/drying conditions on leaching from full\|size samples a n d to optimize dry/wet bulb depression for fixation/drying of CCA treated lumber.展开更多
文摘Rates of fixation in chromated copper arsenate (CCA-C) treated red pine (Pinus resinosa Ait.) and southern pine (Pinus spp) sapwood specimens using retention of 1.5, 2.0, 6.4 kg·m?3 are compared at temperature (T) ranging from 70°C to 50°C and 5 different relative humidity (RH) conditions. The samples were investigated using the expressate method to follow chromium fixation. Red pine fixes faster than southern pine under all 11 post treatment schedules. The fixation rates for both species are not significantly different while the blocks were fixed under 6 fixation/drying schedules that differed only in the order of T/RH conditions applied. The rate of fixation of all samples in any fixation stage were reduced when the blocks were fixed under lower humidity conditions in spite of no change in chamber temperature. Some of this influence can be attributed to the effect of humidity on heat transfer into the wood and cooling of the wood surface.
文摘The effects of fixation drying conditions on fixation rates and chemical leachab ility were investigated with CCA-C treated red pine (Pinus koraiensis Sieb. )and southern pine specimens at a retention of 6 4 kg·m -3 , and under 11 post-treatment schedules ra ng ing from 50～70℃ and 5 different relative humidity conditions. These samples w e re monitored by expressing residual liquid and analyzing it for hexavatent chrom ium content. Samples were subjected to AWPA E11-97 (AWPA 1997) standard leachi n g tests after fixation. Generally, red pine fixed slightly faster than southern pine for most fixation conditions. High temperature, high humidity, fixation co nditions during the fixation/drying schedules resulted in faster fixation and lo wer leaching of chromium and arsenic elements compared to low humidity condition s. Copper leaching showed no significant difference under 11 fixation /drying co nditions for both species. All of the CCA components were leached significantly more in red pine than southern pine. Further work is needed to examine the effec ts of different fixation/drying conditions on leaching from full\|size samples a n d to optimize dry/wet bulb depression for fixation/drying of CCA treated lumber.
