Your search resulted in 6 documents.
Model of termite distribution in Portugal - Follow-up
2003 - IRG/WP 03-10470
In Portugal, subterranean termites of the genus Reticulitermes are indigenous and a well-established pest of wood in service. Mapping their distribution has therefore become important. A field sampling campaign was established along a North-South transect based on 50x50 km cells (Universal Transverse Mercator grid system, UTM). A variety of typical habitats, ranging from forest sites of Eucalyptus, Pinus, Pseudotsuga and Quercus, to scrubland and low vegetation, was included. The universal presence of the termites underlined the difference between the field distribution of termites and the occurrence predicted by risk modelling. In countries like Portugal, where termites can be found in suitable habitats almost anywhere, the assessment of risk requires more attention to construction type and the immediate surroundings.
T Nobre, L Nunes
Effect of climate, species, preservative concentration and water repellent on leaching from CCA-treated lumber exposed above ground
2001 - IRG/WP 01-50178
Few studies have examined leaching of chromated copper arsenate (CCA) from treated wood in above ground exposures due to the assumption that leaching is less severe compared to wood in continuous contact with soil or water. However, a significant portion of CCA treated wood is used for above ground applications, exposing considerable volumes of the preservative to precipitation and potential leaching. This paper presents preliminary results of a one-year study that continuously monitors CCA leaching from above ground, naturally exposed 5.08 cm x 15.24 cm (2 x 6 inch) dimensional lumber. Three wood species, southern yellow pine (Pinus spp.), jack pine (Pinus banksiana Lamb.), and black spruce (Picea mariana (Mill.) B.S.P.), along with two preservative concentrations and one commercial water-repellent are evaluated for their effect on leaching rates. Preliminary leaching results indicate significant differences between wood species, treating solution concentrations, and the use of water repellent. In addition it appears that climatic variables affect elemental leaching of copper, chromium and arsenic differently. However, the exact effects of climatic variables are inconclusive at this time. Upon completion, this study will offer a substantial amount of leaching data to validate the findings of previous leaching tests, and provide insight into the leaching mechanism of CCA-treated lumber in above ground exposures.
J L Taylor, P A Cooper
Developments in unsterile soil soft rot testing
1984 - IRG/WP 2210
Two unsterile soil test methods, the soil burial technique and a method using vermiculite burial with soil inoculation, were compared using different soils to determine their effectiveness in evaluation of wood preservatives against soft rot. Isolation of fungi and microscopy of decayed wood indicated that both methods produced accelerated soft rot attack in treated and untreated birch. Vermiculite burial with soil inoculation produced significantly higher and consistent weight losses over the range of preservative concentrations allowing more confidence in threshold retention selection.
P A McKaig
Industrial fixation systems: key factors, limitations and optimisation through the use of computer simulation modelling. Discussion paper
1994 - IRG/WP 94-40026
This paper briefly describes four fixation operative in the Netherlands, namely: circulating and non-circulating steam fixation cylinders, steam fixation chambers and controlled climate rooms. The general limitations of industrial practice are reviewed against the background of established fixation theory. The controlling variables, both material and process-related, for fixation processing are specified. The capabilities of computer simulation modelling to highlight and provide solutions to these problems is illustrated.
A J Pendlebury, M Riepen, M J Boonstra, W Gard
Multiple-Phase Pressure (MPP) Process: One-stage CCA treatment and accelerated fixation process. 3. Effect of process variables on sapwood treatment and CCA fixation.
1998 - IRG/WP 98-40114
The Multiple-Phase Pressure (MPP) Process achieves treatment and fixation as combined process using hot CCA, within a 2-3 hour time-frame. Timber is treated to saturation with hot CCA using an empty cell process. During the pneumatic pressure phase, hot solution is held in the wood in an otherwise liquid-free treatment vessel until fixation is >95% complete. This report details a factorial design series of treatments undertaken to determine the effect of key process variables, particularly CCA solution temperature and time held at pneumatic pressure, on the degree of fixation achieved during treatment and the resultant Cu, Cr, As and Total Carbon concentration in kickback solutions. Increasing the CCA solution temperature resulted in greater fixation. At a solution temperature of 75°C, extending the time at pneumatic pressure beyond 60 minutes did not result in any significant increase in preservative fixation.
H Pearson, K Nasheri, J A Drysdale, G Durbin, M E Hedley
Evaluation of variables that influence dynamic MOE in wood decay studies
2009 - IRG/WP 09-20409
The effect of wood moisture content (MC) and outdoor exposure of southern pine lap-joint components on dynamic MOE values was investigated. The use of dynamic MOE as a method of measuring progressive biodeterioration of above ground test samples shows promise, but the accuracy of this method for evaluating test samples subjected to fluctuating environmental conditions has not been reported. The results of this study show that fully water saturated samples had consistently lower MOE values than those obtained at lower MC levels. After the MC was reduced from saturation by about 30%, variation in MOE with changes in MC down to the fiber saturation point were minimal. Outdoor exposure of the test samples also influenced the MOE. After an initial period of outdoor exposure, slightly lower MOE values were obtained for all of the test samples. However, subsequent MOE measurements after additional outdoor exposure were fairly consistent and did not show a trend towards either lower or higher values. For some test samples it was not possible to obtain reliable frequency measurements, resulting in their exclusion from the study.
D Nicholas, J Shi, T Schultz