Pathogen detection and identification have been vastly improved with advances in genomics; however, knowledge gaps remain around efficacy and use in wood commodities, especially in regulatory settings. In part one of this project, we compared detection efficacy of different methods on common export and import forest products. In-situ detection was more sensitive than traditional isolation, with 100% detection rates for some methods. However, there were several false positives in control samples. False positive detection of quarantine pathogens on wood products could be a serious problem in trade. The goal of part two of this project was to determine the cause of the false positives. In addition, we continued to compare detection methods by looking at point of care detection with a portable qPCR system and using RNA assays to test pathogen viability. False positives were likely due to DNA contamination persisting through the various wood processing steps. These results confirm the need for additional confirmation of pathogen presence or viability after a positive DNA test. RNA assays failed to detect pathogen presence in most samples. Further testing is needed to determine optimal RNA extraction conditions to provide meaningful results. Point of care detection using portable tools was comparable to laboratory methods and would provide a useful tool for pre-screening commodities for the presence of quarantine pathogens.
A number of test series have been conducted at FPInnovations to evaluate the lateral resistance, fire resistance, and acoustic performance of the new Midply shear wall configuration. The results showed that the seismic force modification factors prescribed in the NBCC can be used, along with the enhanced lateral strength and stiffness. Moreover, with some minor design
considerations, it was found that the new Midply with the resilient channels and insulation materials in both sides of the wall and both cavities can provide at least 1 hour of fire-resistance rating and provide at least an ASTC of 47.
Un certain nombre de séries d'essais ont été réalisées à FPInnovations pour évaluer la résistance latérale, la résistance au feu et la performance acoustique de la nouvelle configuration de mur de contreventement Midply. Les résultats ont montré que les facteurs de modification de la force sismique prescrits dans le CNBC peuvent être utilisés, avec une résistance et une rigidité latérales améliorées. De plus, avec quelques considérations de
conception mineures, il a été constaté que le nouveau mur de refend Midply avec les profilés souples et les matériaux d’isolation des deux côtés du mur et dans les deux cavités peut fournir au moins une heure de degré de résistance au feu et un ITSA d’au moins 47.
To improve the accessibility of genomics for the identification of wood inhabiting microorganisms to FPInnovations’ members, we compared three different methods for metabarcoding on environmental DNA (eDNA): cloning with first generation Sanger sequencing, amplicon metabarcoding with second generation Illumina sequencing, and lastly amplicon metabarcoding with third generation, long read sequencing with the portable MinION. We looked at costs for each method, speed, and difficulty. Illumina metabarcoding was the most economically feasible method. Cloning was difficult, being prone to failure and requiring extensive trouble shooting to complete. Illumina metabarcoding must be outsourced which can take more time for project completion; however, little in-house troubleshooting is necessary. Third generation sequencing is an attractive alternative for routine analysis. It is rapid, low-cost, and takes little up-front capital for start-up. However, it may not be feasible if used infrequently given the time required to learn the technology and the rapid expiration of unused flow cells. For occasional projects, it is recommended to outsource amplicon metabarcoding to a facility that sequences either with second or third generation sequencers, including data analysis.
The overall objective of this study is to provide information to building design practitioners that will help to improve accuracy of hygrothermal models and enable them to better use these models to predict the durability and thermal performance of wood-based building envelopes. To achieve this, hygrothermal models using WUFI Pro software are validated with experimental data obtained from five wood-frame wall assemblies, with different insulation and vapour control strategies, exposed to the climatic conditions of Vancouver from October 2018 to May 2020. This exercise provides a set of model input parameters that the practitioner can use to assess similar structures exposed to similar environmental conditions. Sensitivity analysis is conducted on the model input parameters to establish which are the most important in obtaining a good fit to experimental measurements, and therefore accurate prediction of assembly performance. There is also discussion on limitations of the hygrothermal model.
The definitive guide for the mass timber design and construction of tall buildings has been updated to align with changes to national codes and standards. It builds on 12-storey mass timber gravity systems as an Acceptable Solution in the 2020 edition of the National Building Code, and targets supporting Alternative Solutions that will enable wood to be used beyond 12 storeys.
To download the book, go to: https://web.fpinnovations.ca/tallwood/
The Canadian government published a new
regulation on the formaldehyde emissions from
composite wood products which prohibits the
import, sale or offer for sale of composite wood
products that emit formaldehyde beyond
established limits. The new law will come into force
on January 7, 2023.
Le gouvernement du Canada a publié un nouveau
règlement sur les émissions de formaldéhyde des
produits de bois composite qui interdit
l'importation, la vente ou la mise en vente de
produits de bois composite qui émettent du
formaldéhyde au-delà des limites établies. La
nouvelle loi entrera en vigueur le 7 janvier 2023.
This InfoNote summarizes the verification and validation that the current design requirements of Annex B of CSA O86 can also be applied to small framing members used in unprotected and protected lightweight wood-frame assemblies, e.g., walls and floors. With minor editorial changes, the scope of application of Annex B of CSA O86 could include all wood and wood-based products listed in CSA O86, regardless of their original and residual dimensions.
Originally developed in Europe, self-tapping screws (STS) have become the proprietary fastener of choice in recently built mass timber buildings in North America. STS offers some advantages over other types of fasteners, such as (a) installation of STS inside wood members is easier as it does not require pre-drilling of holes inside members, (b) the yield moment, torsional strength and tensile strength of STS is comparatively high as the material forming the screw is usually hardened after rolling the thread, (c) the stiffness of the resulting connection is higher and the chances of slipping are less (Frese and Blass, 2009), and (d) STS with long threaded lengths makes it feasible for use in large structural members, e.g., mass timber products.
Recently, issues have been raised on failures of STS due to shrinkage and swelling of wood products resulting from moisture content changes, particularly during construction in the coastal climates. Failures of STS have been reported by structural engineers and contractors of several mass timber projects in NA. This has greatly increased the liability of practitioners involved in mass timber construction.
This project will investigate the material properties of several types of mass timber products and self-tapping screws. These material properties will be used in an analytical and numerical prediction model to describe the behaviour of self-tapping screws in mass timber products under moisture content variation.
This article in the Journal of Commerce highlights FPInnovations Sustainable Construction spotlight series. Experts at FPInnovations believe using wood technology could play a major role in helping Canada meet its climate goals. This article may be accessed on the Journal of Commerce's website: https://canada.constructconnect.com/joc/news/resource/2022/06/fp-innovations-pushes-wood-as-solution-to-climate-goals-affordable-housing
The full FPInnovations In the Spotlight series can be accessed at: https://web.fpinnovations.ca/in-the-spotlight-sustainable-construction/
La construction massive en bois est relativement nouvelle et sera bientôt intégrée dans le Code national du bâtiment du Canada (CNB). Il s'agit d'une solution à base de bois à prix compétitif qui complète les systèmes existants à ossature en bois et de construction en gros bois d’œuvre et constitue une option appropriée pour certaines applications qui utilisent actuellement du béton, de la maçonnerie ou de l'acier.
La construction massive en bois est relativement nouvelle et sera bientôt intégrée dans le Code national du bâtiment du Canada (CNB). Il s'agit d'une solution à base de bois à prix compétitif qui complète les systèmes existants à ossature en bois et de construction en gros bois d’œuvre et constitue une option appropriée pour certaines applications qui utilisent actuellement du béton, de la maçonnerie ou de l'acier.
Mass timber construction is a relatively new type of construction soon to be implemented in the National Building Code of Canada (NBCC). It is a cost-competitive wood-based solution that complements existing wood-frame and heavy timber systems and is a suitable candidate for some applications which currently use concrete, masonry and/or steel.
The objective of this research is to address a knowledge gap related to fire performance of midply shear walls. Testing has already been done to establish the structural performance of these assemblies. To ensure their safe implementation and their broad acceptance, this project will establish fire resistance ratings for midply shear walls. Fire tests will provide information for the development of design considerations for midply shear walls and confirm that they can achieve at least 1-hour fire-resistance ratings that are required for use in mid-rise buildings.
This research will support greater adoption of mid-rise residential and non-residential wood-frame construction and improve competition with similar buildings of noncombustible construction. This work will also support the development of the APA system report for midply walls, which will be a design guideline for using midply walls in North America.
Mid-rise and tall-wood buildings are gaining in popularity in the marketplace. Compared to the traditional low-rise buildings, wind-induced vibrations need to be controlled in taller buildings. Due to the lightweight nature of wood construction, wind-induced vibrations are larger in amplitude when compared to buildings built with heavier materials, such as concrete. The NBCC design method requires natural frequencies and damping ratios as inputs (NRC 2015). However, there is little data available about mid-rise and tall-wood buildings' dynamic performance (i.e., frequencies and damping ratios). Lack of data and experience of the wind-induced vibration performance of wood buildings can result in unsatisfactory design of mid-rise wood buildings, which can undergo excessive wind-induced vibration. It can also result in unnecessary overdesign of mid-rise and tall-wood buildings with increased construction costs.
Design for Disassembly and Adaptability (DfD/A) is a sustainability approach that can help extend the lifespan of buildings, reduce generation of construction waste at the end-of-life and reduce construction’s footprint as well. This study qualitatively assesses six light wood-frame exterior wall assemblies designed for thermal performance. The assemblies studied are typical of low- and mid-rise wood buildings.
Results indicate that the exterior wall systems tested against the evaluation grid have a score of 15 points out of 40 points. Mere focus on thermal performance with no attention to deconstruction of components at the end-of-life is the reason for the poor score received from the evaluation. Findings indicate the need for incorporating DfD/A principles at the early-design stages of systems.
FPInnovations’ three-generation floor vibration-controlled design methods in NBCC and CSA O86 ensure market acceptance by consumers. Since 1990, there have been very few consumer complaints. This reinforces the use of wood as a quality building material and contributes to expanding market shares of wood construction in Canada.
Comme l'ont démontré le développement et la mise en oeuvre des codes des méthodes de conception de troisième génération pour lutter contre les vibrations des planchers, FPInnovations joue un rôle important au Canada et à l'échelle internationale dans les comités de codes et de normes visant à protéger les consommateurs et l'industrie du bois et contribue à la croissance continue du marché de la construction en bois à l'échelle mondiale.
