Use of wood products in multi-storey residential buildings: views of Swedish actors and suggested measures for an increased use

ABSTRACT

Many studies have shown that wooden buildings in general have a lower climate impact than buildings built of conventional materials such as concrete and steel. In Sweden, however, only about 10% of the multi-dwelling buildings are built with timber frames. The goal of this empirical study is to provide a broad picture of the views of Swedish actors regarding the use of wood products in multi-storey residential buildings and suggest measures for an increased use. A questionnaire concerning the use of wood products in construction was sent out to Swedish developers, main contractors, and architects and 100 answers were received. The study shows that the views of the groups of actors differ in some respects and factors that may either facilitate or be obstacles to an increased use of wood products were identified and discussed.     

Biodeteriorating agents associated with three tropical timber species

Biodeteriorating agents are major problems of wood particularly in tropical Africa. Biodeterioration is widely observed in light coloured hardwood species especially Celtis mildbraedii, Ceiba pentandra and Pterygota macrocarpa. To determine biodeteriorating agents associated with these degradable woods, logs of C. mildbraedii, C. pentandra and P. macrocarpa were left for 6 weeks at the loading bay during the dry and wet seasons of the year 2001. The surfaces of logs were assessed for stain and mould after 7, 14, 28, and 42 days of storage. Pterygota macrocarpa harboured the highest fungal population count of 60.3×103 colony-forming units (CFU) with C. mildbraedii harbouring the least at 4.2×10² CFU after a week exposure in the dry season. Fusarium solani and Penicillium citrinum were the dominant surface moulds on log ends of wood samples, while Lasiodiplodia theobromae and Ceratocystis fagacearum were the dominant sapstain fungi. Pterygota macrocarpa and C. pentandra were more susceptible to woodborers than C. mildbraedii because of the lack of true heartwood and richer store of nutrients in its wood cells.     

It’s what’s inside that counts: computer-aided tomography for evaluating the rate and extent of wood consumption by shipworms

Experiments were done to investigate in situ colonization of pine wood blocks by marine wood borers at the mouth of a small mountain river in the foothills of the Eastern Pyrenees. Standardized blocks were recovered after remaining underwater for increasingly long durations, until the available resource was exhausted by the shipworms assemblage that developed. Computer-aided tomography (CT) was used for visualizing and quantifying biogenic structures into the wooden blocks. The biodiversity survey of the wood pieces colonized indicated that up to three species of shipworms shared the resource at the same time. The specific wood consumption rate of Nototeredo norvagica was estimated 185 mm³ ind^?1 day^?1. The quantification of voids created by shipworm crowding indicated that total tunnelling represents, on average, 60% of the initial volume of a wood block, revising upward earlier estimates of wood destruction by 28%. CT analysis provides the quantitative measurements necessary to parameterize individual-based growth models linking wood consumption with the species diversity of shipworm assemblages.     

Crash simulation of wood and composite wood for future automotive engineering

ABSTRACT

Multi material mix is a promising approach to reduce weight and the carbon footprint in automotive engineering at competitive costs. As a result, automotive industry is getting more venturous, exploring and applying other materials than metals and plastics – e.g. fibre reinforced plastics (FRPs). In this context, engineered wood products (EWPs) and wood composites should be considered: Wood composites provide high stiffness, strength, excellent damping, high resistance against fatigue and a very low density at low material costs. It is hypothesized that modern wood composites are competitive to metals and artificial fibre-reinforced materials when designed and applied properly. The application of wood and wood composites in automotive engineering calls for precise and reliable material data, required for initial material selection and later in numerical simulation. In this study, a material model normally used for modelling FRPs was adopted. A material database was generated for three hardwood species, to establish the required material parameters and validate material model. Results prove that wooden components can be simulated in crash situations and the selected material model is applicable, even in full vehicle simulation.     

Carbon footprint including effect of carbon storage for selected wooden facade materials

Abstract

The outer facade constitutes a substantial volume of the total consumption of materials used in a building and the need for maintenance of the facade makes it especially interesting from a life cycle perspective. The range of wooden materials and products used for facades has different impacts over the life cycle, but the analyses so far have not included a time-adjusted global warming potential (GWP). Wooden facade materials were assessed with respect to their life cycle carbon footprint based on the environmental product declarations (EPD) and adjusted according to EN15804. The results showed low impacts of untreated Scots pine heartwood (≈1 kg CO₂-eq. per square meter [m²]), medium for thermally modified Scots pine, coated Norway spruce and oil/copper–organic preservative-treated Scots pine (1–5 kg CO₂-eq. per m²) and high for furfurylated Scots pine and acetylated Radiata pine (5–10 kg CO₂-eq. per m²). The results with time-adjustment showed that these methods have a potential large effect on the carbon footprint of wooden claddings. The inclusion of biogenic carbon flows and timing seems to be more important than the difference between the product when biogenic carbon is not included. This fact highlights the importance time-adjusted GWP would have for wood products EPDs.     

A feasibility study of using two-component polyurethane adhesive in constructing wooden structures

This investigation was conducted to determine the feasibility of using a two-component polyurethane （PUR） adhesive, with special waterproof properties, in constructing wooden structures. We designed and conducted tests to compare the shear strength and adhesion performance of PUR with polyvinyl acetate （PVAc） adhesive on block-shear specimens constructed of oriental beech （Fagus orientalis L.）, fir （Abies alba Mill.）, poplar （Populus deltoides Bartr.）, white oak （Quercus alba L.）, sycamore （Platanus orientalis L.） and white walnut （Juglans cinerea L.）. The values of the percentage of wood failure were also determined in specimens constructed with each adhesive. The highest shear strength values of both adhesives were obtained in specimens constructed of beech, while the lowest shear strength values were obtained in fir and poplar specimens. Average shear strength of the PUR adhesive was 16.5% higher than that of the PVAc adhesive. Specimens constructed of fir, poplar and sycamore were characterised by the highest percentages of wood failure, whereas the lowest average percentages of wood failure were obtained in beech and oak specimens. With the exception of oak specimens, there was no statistically significant difference between percentage of wood failure among the PUR and PVAc adhesives. Generally, the PUR adhesive showed an acceptable adhesion performance on wood materials used in our study.     

生命周期评价体系在我国木材加工领域的应用

生命周期评价(LCA)是评价产品、工艺等对能源与材料使用和环境排放影响的一种评价体系, 在木材加工领域的应用始于上世纪90年代。文中论述了欧美等发达国家在木材加工领域LCA的应用, 从研究林产品碳平衡方法开始, 细化到木质面板、地板生产以及住宅用木制品的LCA研究; 研究范围也从传统的木材加工行业到新兴产品诸如木塑等新产品, 以及目前较为新兴的生物质能源领域。LCA在中国木材加工领域的应用则侧重于传统的木材加工业, 包括木制品、竹制品、木质与非木质复合材料、地板、家具等领域。针对目前我国存在的一些诸如理论和方法上的不足、研究结果代表性不明确、数据质量不高等问题, 提出了研究内容细致化、建立符合中国国情的木材加工业的生命周期评价模型、开发自主评价软件、建立符合中国国情的生命周期数据库等对策     

我国主要木制品产业发展概况

概述了我国主要木制品产业（包括木制家具、木质门、木地板、橱柜、木制玩具及一次性筷子）的发展现状,分析了产业发展中存在的问题,指出了木材资源不足及产品附加值低等问题严重阻碍了我国木制品产业的健康可持续发展。同时,针对木制品产业发展趋势,提出了发展建议,为我国木制品产业未来的健康可持续发展提供参考。     

The amount of wooden material in a closed room and its effect on the reverberation time

Optimal sound-absorbing materials are vital for desirable room acoustics. The effect of wood used for interior wall decoration on the acoustical environment is explored in a controlled room by changing the amount of wall wooden materials. The effect on the interior reverberation time (RT) is reported in this work. The experiment was conducted in a relatively small concrete brick house (approximate dimensions 4.6 × 3.2 × 4.2 m). Results showed that room shape and the arrangement of wooden wall decoration materials were important factors affecting the RT at different receiving positions. As the amount of wall decorating wood materials increased, the interior RT in the house decreased linearly; however, the RT at low frequencies diverged. After the analysis of covariance, all frequency variables were adjusted to the same level and a general regressive formula was developed as RT = C − 0.005 DR. Where RT is the reverberation time (s), DR is the amount of interior wood materials used (%), and the C values were constants that ranged from 0.888 to 1.606 and varied according to the different octave bands. Furthermore, it was found that the increasing influential effect with the DR showed diminishing marginal utility. This means that the influence of DR on RT was not linear, and, therefore, the marginal utility should be considered in order to use wooden panels economically. Part of this report was presented at 53rd Annual Meeting of the Japan Wood Research Society, Fukuoka, March 2003     

纳米木粉在木材工业的应用前景展望

纳米技术作为一个新突破点,在木材工业上也将产生新的技术革命.本文就纳米技术在木材工业上的发展及应用前景进行展望,预测未来纳米技术可能对木材工业产生的影响.木材变成纳米尺寸后,木材的材料特异性质、尺寸效应及其变化机理都可能发生变化.当木粉变成纳米的粒度以后,原来木材理化指标都将发生改变.在细粉状态下进行木材液化可以改变木材液化的方式和成本,使木材液化真正工业化.在复杂木雕制品的加工中,采用RPM技术利用CAD直接将纳米木粉形成各种复杂木雕制品,可能开创一种新的木材加工方法.利用纳米木基复合材料和高分子材料细胞结构重组将开创人造板科学研究的新领域.纳米木粉生产的无污染胶粘剂可代替含甲醛的有毒胶,胶粘剂的绿色革命可能从木材的纳米技术开始.木磁材料和木绝磁材料的研究将使磁材料和绝磁材料生产的成本下降,在纳米材料中,纳米木粉的成本可能是最低的.     

CNZ1─5B型多用途木材干燥窑

本文介绍新设计的ＣＮＺ１－５Ｂ型多用途木材干燥窑及其用于干燥立木地板、竹材地板、阻燃胶合板、曲木家具坯件、鞋楦、卫生筷和纸浆托盘等的工艺要点     

单面交错铺板带翼木托盘的力学性能及试验研究

通过对单面交错铺板带翼木托盘在均布载荷作用下受力变形情况的分析,建立单面交错铺板带翼木托盘的横梁及铺板的弯曲强度和弯曲刚度的力学模型,得出在标准状态下满足弯曲强度和刚度的托盘的各项指标,为单面交错铺板带翼木托盘的设计以及与普通木托盘在承受均布裁荷的托盘的设计和校核提供理论依据.     

A Service Test of Treated Louvres in a Cooling Tower

The performance of wooden louvres treated with four preservatives (Celcure A, copper sulfate + sodium pentachlorophenate, pentachlorophenol and Tanalith C) and exposed in a cooling tower in Pretoria is described. The copper-chrome-arsenate (CCA) preservatives Tanalith C and Celcure A (at retention of 30 kg/m³) protected the louvres very well against deterioration. Untreated Pinus canariensis wood outperformed P. pinaster and P. radiata wood.     

Studies on the control of subterranean termites by inorganic pesticides

Studies on the wood preserving techniques against subterranean termites have been undertaken with a view to promote the use of inorganic indigenous pesticides in our country. The thin films of gelatine solution (glue of animal hides) containing 10% calcium carbonate or 5% copper sulphate as well as sodium silicate solution containing 12% calcium carbonate +10% zinc oxide coated separately on wooden stakes prevented termite attack in soil up to 2, 4 and 5 years, respectively. Whereas control wooden stakes were found to be severely damaged by termites within 6 months. Stakes coated with Solignum^®-white used as standard wood preservative for comparison remained free from termite infestation for a period of 5 years.     

中国木材市场现状、存在问题和发展建议

介绍了中国木材市场供需和进口现状及发展趋势。建议发展木结构房屋和铁路杨木枕木等以人工林为主要原料的木材制品,改变消费观念,促进人造板工业发展,调整人造板消费结构,扩大在建筑方面的应用,以木材工业的发展促进林业的发展。提出扩大非公有制人工林发展,大力进口俄罗斯木材和新西兰木材,以弥补国产木材不足。并建议适当减少热带阔叶木材进口,以保护全球生态环境。     

Effects of basic density,annual growth and drying schedule on selected quality factors of dried Siberian larch (Larix sibirica) timber

Abstract

Siberian larch (Larix sibirica Ledeb.) timber is suitable for many uses in the mechanical wood industry. Drying it without any decrease in value, however, is difficult and slow. The purpose of this research was to compare the drying quality of Siberian larch timber dried with three different conventional schedules taking into account the density and annual growth of wood. Five drying tests were performed. The final moisture content (MC), MC gradient, cracks, deformations (bow, crook, twist and cup) and case hardening were measured from the dried timber. The basic density particularly affected the MC, as shown in the differences regarding dried wood, with the denser wood having higher final MC and MC gradient. It was also found that large annual growth increased some deformations. Most of the measured factors were best after drying at the highest temperatures used; however, a slightly different trend was observed for bow, twist and cup. MC factors and twisting were the most problematic properties in drying according to this study. Sorting Siberian larch timber, particularly according to density, would improve the MC properties of dried timber by ensuring sufficient drying time, as economically as possible, for each timber piece.     

Relationship between density and aesthetic attributes of wood and preference of Malagasy consumers

Context

The knowledge of consumer preferences in wood furniture is crucial for the wood processing industries.

Aim

This study aims to identify the attributes of wood that affect the preferences of consumers from the city of Antananarivo, Madagascar, for wooden furnishings.

Methods

Quantitative measurements of the density and aesthetic properties of 12 wood species were carried out. The properties measured were the colour in the CIEL*a*b* colour space, the texture through greyscale image processing, and the density. Then, the wood specimens were subjected to sensory analysis with 100 consumers.

Results

The results showed that the "density" was a prime criterion in choosing a wood species. Concerning the visual aspect, Antananarivo consumers generally liked slightly dark wood colour (L* around 52), tending towards yellow, with a visible oriented texture. The influence of socio-economic factors was also highlighted.

Conclusion

These results are of prime importance in the search for alternative species to replace precious woods that are becoming rare.     

用意杨压缩木替代传统木梳材料的研究

我国木梳素以小叶黄杨、楠木、枣木、梨木等树种为制梳材料。由于人口膨胀,木梳需求量巨增,制梳原材料渐已匮乏,绵延1 500多年的传统木梳手工艺文化正面临消亡的威胁。笔者选择速生树种——意杨为制梳材料,按木梳实用功能和产业经济的实际需求,对意杨压缩木进行一般物理特性试验,对其木梳制品进行实用和成本分析,最终确定50％左右的意杨压缩木完全能替代木梳传统原材料。     

Impregnation of Scots pine and beech with tannin solutions: effect of viscosity and wood anatomy in wood infiltration

The impregnation process of Scots pine and beech samples with tannin solutions was investigated. The two materials involved in the process (impregnation solution and wood samples) are studied in depth. Viscosity of mimosa tannin solutions and the anatomical aspect of beech and Scots pine were analysed and correlated. The viscosity of tannin solutions presents a non-newtonian behaviour when its pH level increases, and in the case of addition of hexamine as a hardener, the crosslinking of the flavonoids turns out to be of great importance. During the impregnation of Scots pine (Pinus sylvestris L.) and beech (Fagus sylvatica L.), the liquid and solid uptakes were monitored while taking into consideration the different conditions of the impregnation process. This method allowed to identify the best conditions needed in order to get a successful preservative uptake for each wooden substrate. The penetration mechanism within the wood of both species was revealed with the aid of a microscopic analysis. Scots pine is impregnated through the tracheids in the longitudinal direction and through parenchyma rays in the radial direction, whereas in beech, the penetration occurs almost completely through longitudinal vessels.     

Dendrometric analysis of olive trees for wood biomass quantification in Mediterranean orchards

This work focuses on the development of dendrometric algorithms to calculate the volume and total biomass contained in olive trees. This laid the foundation for the use of this methodology as a tool to manage resources from orchards, establishing adequate prediction models for assessing other parameters such as income from raw materials from the cultivation, fruit production, CO₂ sinks, and waste materials (residual wood) used for energy or industry. Dendrometry has traditionally been applied to forest trees. However, little research has been conducted on fruit trees because of their heterogeneous structure. This issue was the first step of this research. For this, the form factors were calculated. This relates to the actual volume of the branch with a model volume, calculated as a revolution solid from the base diameter and length. The shape more approximated to 1 was the cylinder model with a mean value of 0.76 and standard deviation (SD) of 0.23. On the other hand, volume equations were obtained for the branches. The distribution of biomass in the tree was analyzed. It is estimated that 40 % of biomass is located in the stem and 60 % in the crown, and most of the crown biomass is concentrated in the first branches (60 %). Afterwards, occupation factors were calculated to relate the wood volume in the crown to its apparent volume, the mean being 0.005 dm³/m³ and SD 0.0025 dm³/m³. Also, equations for predicting the whole wood in the crown were obtained. In this regard, the best results were obtained when the crown diameter was used (R ² = 0.74). These results could be correlated with the production and quality of the fruit, amount of residual biomass coming from pruning, and LIDAR data, which may indicate a simple, quick, and accurate method for predicting biomass.