Your search resulted in 375 documents. Displaying 25 entries per page.
Some practical implications from recent research on the fixation of CCA preservatives
1975 - IRG/WP 358
The mechanism of fixation of CCA preservatives is briefly described. If the temperature is increased during the primary fixation period, the formation of intermediate fixation compounds is less extensive. The length of the primary fixation period is of practical interest. It is determined by preservative composition and concentration, temperature and wood species. Diagrams are given for Pinus sylv...
S-E Dahlgren
Moderate temperature fixation of CCA-C
1989 - IRG/WP 3522
Several Canadian treating plants are using moderate temperature (40-60C°) fixation chambers to reduce drippage and leaching from fresh CCA treated wood. In this study, chromium reduction and surface leaching properties of CCA-C treated red pine (Pinus resinosa) pole sections were monitored during exposure to temperatures of 50-60C° and 90-100% RH conditions. Chromium-VI concentration in the abso...
P A Cooper, Y T Ung
Protection of rubberwood timber. Part 1: Impregnation with boron preservatives
1989 - IRG/WP 3551
Rubberwood (Hevea brasiliensis) were treated with a 3% proprietary mixture of borax/boric acid using three different treatment schedules i.e. full-cell, full-cell to refusal and full-cell with 12 cycles of vacuum/pressure. Freshly cut samples had mean preservative retentions of 187 kg/m³, 214 kg/m³ and 178 kg/m³ respectively. Pre-air dried samples for one week had retentions of 252 kg/m³, 308 ...
L T Hong, C C K Liew
Gaseous boron treatments of wood and wood products
1992 - IRG/WP 92-3691
Treatment of wood and wood products by gaseous organoborates has now been under study for about 5 years. This technique has potential for boron treatment of a wide range of substrates from solid wood through to wood composite materials such as particleboard or wet and dry formed fibreboards. The vapour treatment technique is proving to be very flexible in that it can be adapted to integrate into a...
A J Bergervoet, R Burton, K Nasheri, D R Page, P Vinden
Studies of the mechanism of chromated-copper preservative. Fixation using electron spin resonance
1992 - IRG/WP 92-3701
Two softwoods and one hardwood species were treated with chromium trioxide, copper sulphate, chromated-copper wood preservative (CCA). The treated wood samples were analyzed during fixation by electron spin resonance (ESR). ESR spectra indicated that more than one Cr(V) species was generated from Cr(VI) soon after CCA treatment. The Cr(V) signal became strong within increased several hours followe...
K Yamamoto, J N R Ruddick
Fire retardant treated wood and plywood: A comparative study
Part III. Combustion properties of treated wood and plywood
2002 - IRG/WP 02-40236
The fire retardant treated and untreated plywood and alder wood samples were prepared with the aim to investigate the effects of the way of treatment on the combustion properties. Alder wood was used for the preparation of plywood. Boric acid and borax were used as fire retardant. The plywood samples were impregnated by using three different methods; first group samples were impregnated by soaki...
S Çolak, A Temiz, Ü C Yildiz, G Çolakoglu
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 sp...
A J Pendlebury, M Riepen, M J Boonstra, W Gard
Development of threshold values for boron compounds in above ground exposures: Preliminary trials
1998 - IRG/WP 98-30179
Boron is increasingly used both as an initial and remedial treatment for protecting wood against fungal and insect attack. While establishing lethal dosages for boron against insects through feeding tests is relatively simple, establishing thresholds for fungal attack poses more of a challenge. Tests using boron dispersed in agar artificially surround the fungus with both boron and excess nutrient...
J J Morrell, C M Freitag, S Unger
Differences and their causes of CCA and CCB efficacay among some softwoods and hardwoods
1991 - IRG/WP 3656
Wood blocks from two softwoods and two tropical hardwoods species treated with different concentrations of CCA, CCB, and combinations of CrO3, CuS04, H3BO3 were subjected to the decay by brown rot fungus, Tyromyces palustris. CCA maintained good effect both in softwoods and hardwoods, while CCB and the other combinations lost their effectiveness after leaching. Chemicals leached from CCA treated w...
K Yamamoto, M Rokova
Economical schedule for boron treatment of rubber wood: Pilot plant investigations
1993 - IRG/WP 93-40002
An economical treatment schedule (15 minutes initial vacuum of 85 kPa; 15 minutes pressure of 1000 kPa; 5 minutes final vacuum of 85 kPa) was arrived at for treating air-dried rubber wood (Hevea brasiliensis) in a pilot plant cylinder. Treating with 3% BAE (boric acid equivalent) solution resulted in a dry salt retention of 13.1 kg/m³. Also, the study showed that green rubber wood can be treated ...
R Gnanaharan, T K Dhamodaran
Effect of compression wood on leaching of chromium, copper, and arsenic from CCA-C treated red pine (Pinus resinosa Ait.)
2000 - IRG/WP 00-30232
In this study, the effect of compression wood formation on the release rate of chromium, copper, and arsenic elements from red pine (Pinus resinosa Ait) was investigated. Wood blocks from red pine containing compression and normal wood portions were treated with a 1.0% CCA-C solution and were then allowed to fix at 23 ± ??2°C (74 ± 4°F) for 0, 6, 24, 48, 96, 192, and 336 hours. After each fixa...
S N Kartal, S T Lebow
Copper based water-borne preservatives: Copper adsorption in relation to performance against soft rot
1987 - IRG/WP 3452
As part of a fundamental study concerned with the performance of copper based water-borne preservatives the adsorption of copper from aqueous solutions by 4 hardwood and 1 softwood species has been studied. Experiments were conducted to determine the influence of solution pH, solution concentration and solution temperature. The results obtained were consistent with an acid form ion-exchange mechan...
P M S Rennie, S M Gray, D J Dickinson
Industrial fixation of chromium based wood preservatives
1990 - IRG/WP 3630
Fixation is an abstract and non-defined process. Nevertheless it is a specified requirement in most impregnation standards. The impregnation industry is facing increased pressure to deliver fixed products and to increase the safety of the handling of impregnated products. Industrial fixation of impregnated wood can be obtained by using different methods. The purpose of the process is to transform ...
T Christensen
A diffusion and reaction model for the leaching of Cr-VI from unfixed CCA-treated wood
2001 - IRG/WP 01-50169
A physical model applicable to the leaching of any substance undergoing a first-order fixation reaction with wood is presented. Using this model and a laboratory leaching experiment with small wood samples immersed in water, the radial and tangential diffusion coefficients and the reaction rate constants of Cr-VI in unfixed CCA-treated red pine (Pinus resinosa Ait.) are measured. Reaction rate con...
L Waldron, P A Cooper
The multi-phase pressure (MPP) process. One-stage CCA treatment and accelerated fixation process
- The process as a new concept in preservative treatment
1997 - IRG/WP 97-40078
The background to current commercial CCA treatment schedules used in New Zealand and fixation processing is reviewed. The limitations of these conventional practices with respect to treated product quality and CCA solution handling issues are defined. A novel, patented treatment schedule has been developed using a combination of hydraulic and pneumatic pressure phases and hot (~ 75°C) CCA solutio...
K Nasheri, A J Pendlebury, J A Drysdale, H Pearson, M E Hedley
Evaluation of the efficiency of industrial kiln type CCA fixation chambers
1996 - IRG/WP 96-40063
Six commercial CCA treating plants in Canada were assessed for the fixation efficiency of their hot air fixation chambers. The wood temperature was measured with thermocouples over the fixation period at different locations in the chamber and at the end of the fixation cycle, the degree of chromium fixation was determined by a boring leaching procedure. There was a great variation in the effective...
A Taylor, P A Cooper
Performance of groundline bandage remedial treatments in western US species transmission poles
1993 - IRG/WP 93-30019
Groundline bandages are an important element in remedial treatment strategies for utility poles in the United States. Several bandages containing new or reformulated components have recently been developed but have not been adequately tested. This paper reports on the degree of diffusion of copper naphthenate, boron, and sodium fluoride from groundline bandages into pressuretreated Douglas-fir, po...
P G Forsyth, J J Morrell
The influence of drilling patterns on the distribution of toxicants from Polesaver Rods in hardwood poles
1994 - IRG/WP 94-30051
Polesaver Rods are solid rods of wood preservative that are used as a groundline maintenance treatment to control biodeterioration in hardwood transmission poles in Australia. The rods are inserted in holes that are drilled in a prescribed manner to distribute the toxicants into the critical groundline region of the poles. To determine the influence of drilling patterns on the distribution of toxi...
W D Gardner, C N McEvoy
Investigation of CCA fixation in wood by sequential extraction. I Determination of CCA component fixation and preliminary extraction results
2002 - IRG/WP 02-50188
The fixation of CCA-C preservative was investigated in sapwood of red pine (Pinus resinosa Ait.), trembling aspen (Populus tremuloides Michx.) and red maple (Populus tremuloides Michx.) at target retentions of 4.0, 6.4, 9.6 and 30.0 kg/m3. Treated wood sawdust was water extracted at close time intervals during the fixation and analyzed for the contents of unfixed hexavalent chromium, total Cr, Cu ...
S Radivojevic, P A Cooper
Remediation of environmental impacts related to inorganic wood preservative chemicals using in-situ geochemical fixation
2001 - IRG/WP 01-50166-17
Use of the inorganic wood preservative chemical chromated copper arsenate (CCA) has resulted in several documented cases of soil and ground water contamination at wood treatment plants due to spills or releases of the treatment chemical. The most significant impact from releases of CCA to the environment is related to hexavalent chromium contamination of ground water. This is due to the relative s...
R M Thomasser, J V Rouse
On the use of probit analysis for assessing the toxicity of wood preservatives
1974 - IRG/WP 244
To elucidate the general character of the action of the toxic material on the fungus, it is sufficient to carry out preservative tests using the previously described procedure, but in doing so, it is necessary somewhat to change the number of specimens and their arrangement in jars. Five concentrations of toxic material are tested simultaneously. For the testing of one preservative ten jars should...
D A Belenkov
Standard and accelerated testing of boron-additive wood protection systems
2005 - IRG/WP 05-30381
The main objective of this research was to determine the effectiveness of boron-additive protection systems for above ground applications by means of field testing. The two field test procedures used are based on the L-joint test described in the European standard EN 330. For the first set up the boron treated timber was coated in accordance with the standard EN 330 system. The second set up is ba...
A Mohareb, J Van Acker, M Stevens
Tool wear for vapor boron-treated composites
2001 - IRG/WP 01-40209
A series of composites, including oriented strandboard and medium density fiberboard, were treated via vapor boron technology. Treated samples were compared to untreated composites using a tool force measuring technique. Tool forces measured with a dynamometer indicated a positive effect of boron addition. Visual and SEM examination indicated a wider wear zone on the rake face of the tool for the ...
W A Jones, H M Barnes, H A Stewart, R J Murphy
A comparison of the diffusion of boron from two types of solid preservative rods into the heartwood of 3 Eucalypt pole species
2000 - IRG/WP 00-30227
The ability of boron to diffuse from polyborate and boron/fluoride rods through the heartwood of three eucalypt pole species (blackbutt, red ironbark and spotted gum) was examined. The aim was simply to determine the effects of rod type, wood species and time on the longitudinal diffusion of boron in eucalypt heartwood. Rapid diffusion of boron from polyborate or boron/fluoride preservative rods o...
P J Beutel, P D Evans
A study of the rate of fixation of various chromium-containing preservatives
1991 - IRG/WP 3653
Denmark, and Scandinavia in general, has perhaps the widest range of approved industrial wood preservative types in the world. As an aid in setting realistic fixation periods, work was undertaken to investigate the rate of fixation of chromium in CCA salt, CCA oxide, CCP, CCB, CC and CCF formulations at summer and winter temperatures. The rate of fixation measured in terms of the concentration of ...
L B Sheard