A transparent coating with long-term performance could help wood maintain its share of residential markets against material substitution and potentially expand markets in recreational property and non-residential buildings. While transparent coatings can be made reasonably resistant to UV some UV likely penetrates to the wood and by necessity clear coatings are transparent to visible light. Visible light can also cause damage over the long term thus the underlying wood needs additional protection. Four novel UV protection systems were tested as pre-treatments on uncoated wood and under three coatings, a water-based film forming coating, a water-based acrylic varnish and a solvent based water repellent. Samples were exposed to natural weathering facing South at 45° at a test site in Gulfport, Mississippi, in collaboration with the USDA Forest Products Laboratory. The test material was inspected every six months for discolouration, mold and stain, coating water repellency, flaking, erosion and cracking and substrate condition. After 24 months exposure, coatings over the combination of UV absorber and lignin stabilizer identified by Stephen Ayer were performing better than the same coatings applied over the combination recommended by Ciba and coatings over both pre-treatments were performing substantially better than controls with no pre-treatment. Projection of fitted curves beyond the data appears to indicate that pretreatment may double the life expectancy of the coating. There was no consistent effect of the synergists on either combination at this time.
Commercial and multi-family residential construction represents a growth area for the Canadian wood products industry. To capitalize on this opportunity, a thorough understanding of the necessary products and system attributes will be essential. Adequate levels of noise/sound control in multi-family buildings are mandatory requirements of building codes in Canada, the United States, Europe, and most developed Asian countries. In many jurisdictions, these requirements are as strictly enforced as those for structural sufficiency and fire safety. Much effort has been spent on evaluation of sound transmission class (STC) and impact sound insulation class (IIC) of floor and wall assemblies and on studies of flanking transmission in multi-family dwellings in Canada. However, continuing occupant complaints of poor acoustic performance in wood-frame buildings that appear to have been built according to wall and floor construction practices recommended in building codes suggest the existence of gaps in current noise control techniques.
Forintek initiated this project to investigate the relative importance of noise transmission in wood-frame residential buildings in comparison with other building serviceability issues, and to conduct a pilot study to examine construction designs of wood-frame buildings that exhibit unsatisfactory and satisfactory noise control and to identify existing gaps in current noise control techniques.
A literature review and survey of 123 occupants of wood-framed multi- and single-family residential buildings was conducted to determine the relative importance of noise transmission in comparison with other building serviceability attributes. Case studies were conducted on construction details and designs of six new wood-frame condominiums and one single family-house that were built according to code requirements and recommendations for controlling noise transmission.
We found that the general public had high expectations regarding adequate acoustic privacy. Even single- family house builders considered low sound transmission important. The multi-family building occupants ranked “sound insulation” the most “important” serviceability attribute, while single-family occupants were most concerned with “water penetration and condensation”. The lowest level of “satisfaction” was given by all respondents to “noise transmission” for their current residences, including single-family occupants, who had ranked it as not being so “important”. The case studies revealed that, current construction practices were much more effective in controlling airborne sound transmission than impact noise. The footfall noise transmission from stairs through the walls is still an unresolved issue that is not considered in the current Canadian Building Code. The low frequency footfall noise transmission between vertically-stacked units was the common complaint in some of these buildings. With no requirement for impact sound insulation in the current National Building Code of Canada, and with our existing knowledge gap concerning low frequency footfall noise transmission problems and solutions to control them, builders, acoustics consultants and design engineers have simply tended to blame wood building materials for noise-related complaints.
We concluded that if we are to satisfy the occupants of both single-and multi-family wood-frame buildings and to provide confidence for builders and design engineers in wood-frame construction with satisfactory acoustic performance, a much greater effort is needed to improve sound insulation including development of better sound insulated wood-frame systems and building materials as well as retrofitting techniques. Acoustic performance will be a critical factor for the wood products industry in gaining a greater share of the multi-family construction market and in competing with other building materials.
On retrouve actuellement en milieu industriel diverses technologies de scanneurs d’équarris utilisant des configurations soit linéaires ou transversales pour l’optimiser le débitage secondaire. Puisque aucune donnée n’est disponible quant à la performance ou les avantages d’un système par rapport à un autre, Forintek a entrepris de réaliser une étude comparative.
Un échantillon d’équarris a été mesuré dans des conditions industrielles avec trois scanneurs différents, un transversal et deux linéaires, ainsi qu’en laboratoire à l’aide de la technologie de rayon x, servant de référence. La comparaison des rendements obtenus avec chaque scanneur étudié a été réalisée par le biais de simulations à l’aide du logiciel Optitek. Comme la plupart des systèmes de positionnement d’équarris présentent un niveau de précision limité, des erreurs de positionnement ont été appliquées par simulation pour obtenir des résultats réalistes.
Les résultats ont démontré que les erreurs de positionnement ont un impact majeur sur l’optimisation du débitage secondaire. Avec le niveau d’erreur moyen observé en industrie, aucune technologie de scanneur ne se démarque nettement des autres. Toutefois, en améliorant considérablement la précision des systèmes de positionnement, on pourrait observer la tendance suivante : le scanneur transversal s’avèrerait le plus précis avec un niveau d’efficacité de 2 % supérieur au système linéaire à 4 caméras, et ce dernier serait de 2 % supérieur au système linéaire à 2 caméras. La technologie du rayon x offrirait un excellent potentiel d’amélioration par rapport aux technologies actuelles puisqu’elle permettrait d’accroître l’efficacité du débitage de 6 % en ne considérant aucune erreur de positionnement.
Cette étude compare les performances des différentes machines de classement MSR utilisées actuellement dans l’industrie canadienne du bois de sciage. Cinq machines ont été retenues : La HCLT-7200 de Metriguard, la Dart de Eldeco, la TMG du CRIQ, la Dynagrade de Dynalyse AB et la XLG de Coe Mfg.
Using automation to maximise yield from increasingly rare and costly raw materials is a solution that can help secondary wood producers improve their profitability. By integrating an automated defect detection system, lumber producers can potentially increase production output and grade recovery, helping them to strengthen their strategic business advantage.
To develop a reference tool to assist in the choice of an appropriate defect detection system, Forintek conducted a detection capacity evaluation of commercially available equipment. Nineteen (19) manufacturers who work in the area of defect detection in lumber were contacted; of these, four agreed to participate in the study.
The project objectives were based on requests from the producers: the evaluation focussed on the detection capacity of specific defects and not on the performance of the overall system. Defects were identified and an experimental evaluation was conducted to determine if the equipment recognised the defects or not. A decision tool based on a multi-criteria analysis has been proposed in the completed project report, to help producers identify the most appropriate defect detection system. However, no evaluation can be offered for the overall performance of the systems assessed, as production needs differ from producer to producer.
Today's machine centres are being increasingly automated but often operate as a collection of isolated machines run by a variety of computer systems. Clearly, such heterogeneous computing and control environments present a formidable barrier to the problem of interoperability. Already there are vendors that provide a partial solution to the problem, since they provide methods of interoperability only between machines that they supply. Vendor-specific methodologies are in general proprietary, and do not inter-operate with any other vendor's equipment. What's needed to facilitate widespread machine-to-machine data exchange is a universal methodology to connect to optimizer data, or any data for that matter, with plug-and-play simplicity. In order to enable enhanced data availability and also to lay the foundations for the evolution of process monitoring and control in the sawmilling industry, this project was undertaken to create a common methodology for vendor-neutral data exchange between machine centres, process monitoring and control systems, and business systems.
A task forceª, with members drawn from sawmilling and equipment vendor companies, selected the well-established specifications for data exchange published by the OPC Foundation, a consortium of companies committed to universal data exchange in industry. While these specifications specify standards-based methods for data exchange, the task force recognized that there was an additional layer required to create standard plug-and-play access to sawmill optimizers. This additional standardization layer specifies exactly what data is made available per optimizer type. After testing these ideas for primary breakdown optimizers and PLCs in a sawmill-based pilot project, the task force unanimously adopted the OPC specification and our per-optimizer layer as a practical standard for data exchange in the sawmilling industry.
Given this initial success, however, there needs to be a continuing effort to ensure that the evolving sawmill standards eventually are applied to all optimizer types, and that sawmill managers and executives are aware of their benefits. Continuing effort must ensure that multi-vendor support per optimizer type does not result in tag list fragmentation which would undermine the benefits of standards. The methodologies adopted during this project will never become standard in the sawmilling industry unless the majority of sawmillers demand the standard OPC optimizer interfaces defined by this project.
ª In this document, “task force” is used interchangeably with “working group”. On 21 March 2002, a standards committee was struck from task force members, but soon lost its meaning when the task force adopted an email list approach to collaboration. The email list was much more inclusive and therefore much larger, and became the defacto “working group”. By project end, the working group consisted of 40 members.
Wetwood, or water pocket, has higher moisture content and lower permeability than normal wood, which cause serious problems for lumber drying. The high moisture content of wetwood usually requires relatively long periods for adequate drying; consequently, it causes a high risk for developing checks, splits, crook, bow and twist of lumber in kiln drying. These problems have not been solved by any physical, chemical or mechanical methods yet. Using biological method to pre-dry lumber containing wetwood is a new concept introduced in this project. Wetwood is formed by bacteria growth inside normal wood. Some fungi are able to kill bacteria and to utilize foetid liquid produced by these micro-organisms. Consequently, the permeability of wetwood can be increased and the lumber drying rate can be improved. The present project intends a research on biological method to pre-dry lumber containing wetwood, and to evaluate efficacy and economic benefit of such a biological treatment.
Trees of balsam fir, sub-alpine fir and aspen were felled and cut into lumber. Isolation of causal agents was conducted from wet pockets of these wood species by using peptone agar and malt extract agar media. A total of 319 cultures were obtained from the wetwood of these three wood species. Three bacteria and two yeasts were isolated from balsam fir wetwood, 2 bacteria and 1 yeast were more frequently isolated from aspen wetwood, and 2 bacteria and 5 yeasts were obtained from sub-alpine fir. Two bacteria were isolated from the wetwood of all 3 wood species: Shigella sonnei and Pseudomonas fluorescens. Other bacteria and yeasts isolated were identified as Aerococcus viridans, Chryseomonas luteol, Candida boidinli, C. zeylanoides, Cryptococcus albidus, C. laurentii, C. terreus, and Rhodotorula mucileginosa. In addition to these identified bacteria and yeasts, two other yeasts isolated from balsam fir and sub-alpine fir wetwood were unabile to be identified.
Six bacteria and yeast isolates were re-inoculated on normal wood of balsam fir; they were A-a (a bacterium isolated from aspen and identified as Shigella sonnei), A-c (a yeast isolated from aspen and identified as Cryptococcus laurentii), B-a (a bacterium isolated from balsam fir and identified as Shigella sonnei), B-c (a mixture of 2 bacteria isolated from balsam fir and identified as Shigella sonnei and Aerococcus viridans), Y-2 (an unidentified yeast isolated from balsam fir), and SaB-2 (a bacterium isolated from sub-alpine fir and identified as Shigella sonnei). The result showed that all of these micro-organisms caused wetwood formation on inoculated normal wood samples in 2 weeks. This result indicates that wetwood formation in trees is not caused by only 1 micro-organism but is more likely caused by several species (either bacteria or yeasts) that can colonise well in the wood of trees. The moisture contents (MC) of the inoculated wood blocks increased from 41.2% to 220-240 %, whereas the MCs of the control samples submerged in a liquid culture medium without inoculation reached only 110%. When control samples were dried to a MC of 13%, the inoculated wood samples still had MCs between 80% and 105%. This result indicates that drying lumber containing wetwood will take double the time required to dry normal lumber without wetwood.
An antagonist test using fungal candidates was conducted on agar plates. In this test, 6 potential fungal antagonists and 6 wetwood causal agents (WCA) were used. The six fungal antagonists were Gliocladium roseum (Forintek bioprotectant), a white isolate of Ophiostoma piliferum (Cartapip), a white isolate of Ceratocystis resinifera (an anti-sapstain biological agent produced by Chantal Morin at Laval University), Oidium sp.A (a white fungus in Deuteromycetes isolated from Jack pine logs, DP3/5B-3a, 1998), Oidium sp. B (a white fungus in Deuteromycetes isolated from balsam fir logs, DF3/1B-1b, 1998), and Phaeotheca dimorphospora (a biological control agent of tree disease from Laval University). The six wetwood causal agents were A-a (a bacterium isolated from wetwood of aspen), A-c (a yeast isolated from wetwood of aspen), B-a (a bacterium isolated from wetwood of balsam fir), Y-2 (a yeast isolated from wetwood of balsam fir), SaB-2 (a bacterium isolated from wetwood of sub-alpine fir), and SaY-4 (a mixture of a yeast and a bacterium isolated from wetwood of sub-alpine fir). The results showed that Oidium sp.A and Oidium sp.B were the most effective against all 6 WCA inoculated; they reduced growth of the WCA in 7 days and completely absorbed colonies of WCA in 11 days. G. roseum, O. piliferum, and C. resinifera were moderately effective against 5 WCAs, but not effective on bacterium A-a that was isolated from aspen wetwood. P. dimorphospora was the least effective against any of these WCA.
The three promising fungal antagonists, Oidium sp., G. roseum and the white isolate of O. piliferum, selected from agar plate test were used for a following antagonist test on balsam fir wetwood blocks in the laboratory conditions. This test was conducted on small wetwood samples (2 x 4 x 1 inch) in incubators at 25°C and two relative humidity ranges (100% and 75% RH). The results showed that all these three fungi were able to establish on wood surfaces and able to reduce wetwood contents. At 25°C and 75% RH, Oidium sp. was the most effective to reduce wetwood content in samples, followed by G. roseum, and then by O. piliferum. G. roseum and Oidium sp. not only reduce wetwood content, but also inhibit mold growth and wood stain, compared with untreated control samples. At 25°C and 100% RH, the moisture contents of treated and untreated samples were not changed in any week of the testing period. This result indicates that biological pre-dry wetwood samples should not be conducted at this high relative humidity condition.
A test was conducted to investigate the ability of Oidium sp., the wetwood control candidate, against sapstaining fungi on wood. The results showed that if balsam fir wood wafers were inoculated with Oidium sp. 3 days before the staining fungi, no staining fungi grew on these samples. If wood wafers were inoculated with Oidium sp. and staining fungi at the same time, samples were covered by both Oidium sp. and the staining fungus Ophiostoma piceae in a ratio of 50 to 50%. If wood wafers were inoculated with the staining fungi 3 days before Oidium sp., samples were absolutely covered by the staining fungus and fully stained.
This project aimed to develop technologies for protecting OSB raw materials from biodegradation and to explore biological pre- or post-treatments to increase the durability of panels so they would better resist mould, stain and decay. The project was conducted in five parts. Part one involved developing a biological technology to protect OSB raw materials from biodegradation. The results of this part of the work showed that all untreated logs, with or without bark, were seriously degraded by moulds, stain and decay fungi after a summer storage period of five months. The logs with bark were more degraded than the debarked logs, and the log ends were more degraded than the middle sections. After summer storage, 55% to 83% of the wood was degraded in untreated logs. The biological treatment was effective, only 4% to 16% of the wood in treated logs was infected by various fungi after a five-month storage period. Furthermore, the biological treatment was more effective on logs without bark than logs with bark, and more effective on yellow birch and aspen than on red maple. After one year in storage, the total infection rates of untreated logs ranged from 68% to 91%, whereas the rate for biologically treated logs ranged from 27% to 49%. Strands cut from untreated logs contained 50% to 75% of grey or blue stained strands, whereas those cut from biologically treated logs contained 10% to 25% of such strands. Panels made using biologically treated logs had the lowest thickness swelling (TS) and water absorption (WA) values compared with panels made using fresh-cut logs and untreated stored logs. The other physical and mechanical properties of the various panels made for this test were comparable. For the mould resistance, all panels made from fungal treated logs had better mould resistance than those made from freshly cut and untreated logs. Panels made of strands cut from fungal treated debarked logs had better mould resistance than the panels made from fungal treated bark-on logs.
The second part of the research consisted of investigating antifungal properties of barks from various wood species. In this part, antifungal properties of barks from 6 wood species: aspen, red maple, yellow birch, balsam fir, white spruce and white cedar were screened in a laboratory test against moulds, staining fungi, white-rot and brown-rot fungi. Based on the colony growth rate of moulds, stain and decay fungi on bark-extract-agar media, white spruce bark was the best at inhibiting growth of these fungi, followed by red maple bark. White cedar and balsam fir bark somewhat inhibited certain fungi tested. Aspen and yellow birch bark did little or nothing at all to inhibit fungal growth.
The third part involved developing a biological treatment technology by using naturally resistant wood species to increase the durability of panels so they would better resist mould, stain and decay. In this part, a series of tests were conducted using various wood species. These tests included a) using white cedar to improve panel durability; b) optimizing manufacturing conditions for producing durable panels with white cedar; and c) using other wood species to produce mould-resistant panels. The results showed that three-layer panels made using white cedar strands in the face layers and aspen strands in the core layer at different ratios were mould and decay resistant. White spruce heartwood-faced panels were highly mould resistant and moderately decay resistant. In addition to being mould resistant, white spruce heartwood-faced aspen panels also had better internal bond (IB), modulus of rupture (MOR) and modulus of elasticity (MOE) properties, compared with aspen panels. The panels with black spruce in surface layer had mechanical and mould-resistance properties that were similar to those with white spruce in surface. The panels with surface layer of Eastern larch heartwood were non-resistant to moulds and slightly resistant to decay, but they had better IB, TS and WA properties compared with the other types of panels.
The fourth part of the research consisted of developing a biological treatment technology by using fungal antagonists to increase the durability of panels against mould, stain and decay. In this part, two major tests were conducted using various fungal species. They were: a) treating wood strands with three antagonistic fungi, Gliocladium roseum, Phaeotheca dimorphospora and Ceratocystis resinifera, to increase OSB panel durability; and b) treating wood strands with a lignin-degrading fungus, Coriolus hirsutus, to reduce OSB resin usage. The results of this part of the work showed that all of the 4 fungal species used grew well on aspen strands in four weeks, and strands in all treatments had normal wood color after incubation. For IB property, panels made of fungal treated strands were better or similar to the control panels. Panels made of fungal treated strands had higher TS and WA values than untreated control panels. For mechanical properties, panels made of fungal treated strands had a slight lower dry MOR and higher wet MOR than control panels. For mould resistance, panels made of fungal treated strands were infected by moulds one week later than the untreated control panels, and reduction of mould infection rates was detected on fungal treated panels within 6 weeks. After 6 weeks, all panels, treated or untreated, were seriously infected by moulds. Reducing resin usage in fungal treated panels did not affect panel density. Compared with untreated control panels, the IB property of panels made of fungal treated strands was slightly increased by using normal dosage of resin or a reduced dosage by 15%, but slightly decreased with a resin reduction by 30%. There was a negative linear correlation of the panel TS and WA properties with resin reduction by using fungal treated strands. For the mechanical properties, panels made of fungal treated strands had lower dry MOR and MOE values, but higher wet MOR values (except for a resin reduction of 30%) than panels made of untreated strands.
The fifth part involved protecting OSB against mould and decay by post-treatment of panels with natural extracts from durable wood species and from fungal antagonists. In this part, three tests were conducted using extracts of white cedar heartwood and extracts of a fungal antagonist. These tests were: a) screening antifungal properties of natural extracts against mould and decay fungi; b) post-treating OSB panels with white cedar heartwood extracts and finishing coats; and c) post-treating OSB panels with fungal metabolites. The results of this part of the work showed that the mycelial growth of all fungi tested (moulds, staining fungi, white-rot and brown-rot fungi) was inhibited by the extracts of white cedar heartwood and extracts of the fungal antagonist, P. dimorphospora, on agar plates. Panel samples dipped with the cedar extracts got slight mould growth on the 2 faces and moderate mould growth on the 4 sides, whereas the panel samples dip-treated with the fungal extracts got the minimal mould infection among the panels tested. The results of the mould test on the post-treated panels with extracts of white cedar heartwood and three coating products showed that slight or no mould growth was detected on any sample dip-treated with the extracts and then brushed with finishing coats. The decay test showed that most post-treated samples had less weight losses than untreated control samples.
Des visites industrielles auprès des producteurs et des utilisateurs de panneaux collés sur chant ont été effectuées afin de définir ce qu’est un collage sur chant de qualité pour les produits d’apparence. Lors des visites, des panneaux collés avec joints de bonne et de mauvaise qualité ont été recueillis pour examen au laboratoire de Forintek. Des mesures effectuées au microscope ont permis d’établir à 0.05 mm la valeur maximale acceptable de largeur du joint de colle d’un panneau. Les principales causes de joints problématiques propres à l’opération de délignage des bandes sont l’éclatement des fibres du bois sur l’arête, la trop grande rugosité de la surface sur chant et la mauvaise rectitude du trait de scie bien que l’angle d’équerre de la scie constitue aussi un paramètre critique. La proportion de panneaux rejetés en usines reliés à ces causes varie de 0.5 à 3 %.
Des mesures de rugosité sur un échantillon de bandes recueillies en usines ont permis d’établir des valeurs représentatives de rugosité sur chant de bandes utilisées à la production industrielle de panneaux. Des mesures de rugosité sur des bandes délignées en laboratoire ont démontré les effets importants du modèle de scie et de la vitesse d’alimentation, ou avance par dent, sur les valeurs de rugosité sur chant. Des mesures effectuées sur des bandes délignées à partir de scies usées ont démontré que la rugosité sur chant ne permet pas de détecter le niveau d’usure d’une scie, les valeurs moyennes de rugosité étant similaires à celles de bandes délignées à l’aide de scies bien affûtées.
Suite à la fabrication de panneaux en laboratoire à partir de bandes présentant une large gamme de rugosité sur chant, des mesures ont démontré l’augmentation de la largeur des joints de colle, l’augmentation de la proportion des joints de largeur supérieure à 0.05 mm (trop apparents) et la diminution de la résistance en cisaillement des joints de colle avec l’accroissement de la rugosité sur chant des bandes. Les paramètres de collage (type de colle, pression aux serres, température ambiante, etc.) furent gardés constants pour la fabrication de l’ensemble des panneaux.
Finalement, en fonction des résultats obtenus dans le cadre de cette étude, des valeurs de rugosité sur chant Ra et Rt de 9 µm et 80 µm respectivement peuvent être considérées comme des valeurs permettant la fabrication à grand volume de panneaux avec joints de colle de qualité, une augmentation de la rugosité sur chant résultant en des joints de colle plus apparents.