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A comparative life cycle study of alternative materials for Australian multi-storey apartment building frame constructions: Environmental and economic perspective
Abstract
The building construction sector contributes to a quarter of the total Australian Greenhouse gas emissions. These emissions are mainly attributed to the use of energy intensive materials. To achieve better environmental benefits and cost saving, the utilisation of wood-based construction materials is currently attracting attention. However, the manufacturing of engineered wood products consumes large quantities of chemicals and energy, which may have adverse environmental impacts. Therefore, a life cycle study was conducted to compare various materials for constructing the structural frame of a 4-storey apartment building compliant with the Australian building codes. Five alternatives were assessed: Laminated Veneer Lumber (LVL) manufactured from early to mid-rotation hardwood plantation logs (LVLm), LVL manufactured from mature hardwood plantations (LVLh), LVL manufactured from mature softwood plantations (LVLs), concrete and steel. The functional unit was defined as the whole building structural frame. Global Warming Potential (GWP), Acidification, Eutrophication, Fossil Depletion, Human-toxicity Potential (HTP) and Life Cycle Cost (LCC) were evaluated. The LVL generally performed better than concrete and steel structural products. Particularly, LVLm had the lowest GWP (2.84E4±233 kg-CO2-eq) and LCC ($128,855 ± 2797), which were less than a quarter of the concrete option. However, the usage of chemical preservatives and phenol-formaldehyde adhesive during the LVL production and treatment caused the HTP impact to be higher than the steel option. Monte Carlo Analysis showed that while the LVL options presented a higher sensitivity to the combined uncertainties, the overall ranking of the five options remained the same. Therefore, the inclusion of wood-based material in structural elements may significantly contribute to reduce the environmental impacts and the LCC of the construction sector.
... The service life of structural materials is contingent upon their strength and durability. In Australia, the average building service year is generally set to 50-60 years (Lu, El Hanandeh, & Gilbert, 2017;Tokede et al., 2022). Table 1 highlights the energy modelling assumptions conducted for the case-study building. ...
... Equation (1) exhibits the calculation of the LCC of the benchmark building structure. (Aslay & Dede, 2024;Lu et al., 2017). However, CIU or recurrent costs are associated with the building use phase and hence are considered as future costs. ...
... The Reserve Bank of Australia specifies the discount rate as 4.9% for 2024. Given the changes in the global economic indices, uncertainties related to the rate can range from 3.9% to 5.9% for the LCC (Lu et al., 2017). The number of replacements and repairs required during the use phase for different building materials in the scenarios are determined using their expected service-life values and the expected life of the building (Aslay & Dede, 2024;Morales et al., 2021). ...
... Moreover, the topics show multiple connections with each other. Especially, for this period, environmental research starts to cover and gain significance at macro levels, studying the environmental impact on economies, communities, and cities [71,75,76]. The term concrete in the network was related mainly to environmental topics such as carbon footprint, life-cycle cost, energy analysis, Co2-emission, and emissions, as seen in Figure 13. ...
... The topics impact and sector were mainly associated with environmental topics [53,67,69,75,[77][78][79]. In all period articles, the keyword was added via Keyword Plus, which does not add specific information. ...
... Other topics related to impact including environmental-impact, sound-impact, and climate-impact, due to the low frequency of the keywords, were not added to the cluster analysis. The topics impact and sector were mainly associated with environmental topics [53,67,69,75,[77][78][79]. In all period articles, the keyword was added via Keyword Plus, which does not add specific information. ...
The increase in population and urban migration has incentivized the construction of mid-rise and tall buildings. Despite the incremental rise in vertical construction, there are still investigation gaps related to high-rise buildings, such as carbon emissions and the use of low-carbon materials in tall structures. Timber presents a potential sustainable solution for mid-rise and tall buildings. The history of topics in timber building investigations began with the material characterization of innovation in construction technologies such as cross-laminated timber (CLT) and practical topics like construction collaboration, sustainability, engineering, and construction science. To identify potential topics and understand the research history of mid- and high-rise timber buildings, a bibliometric analysis is proposed. Therefore, this article aims to perform a bibliometric analysis with a science mapping technique to categorize and analyze the evolution of mid- and high-rise timber building research topics and identify the most relevant trends and current challenges. A co-occurrence keyword analysis was performed with the software SciMAT to analyze the evolution and actual trends of mid-rise and tall timber buildings. The results show an evolution in the investigation topics from timber frame elements to mass timber and CLT for high-rise buildings, which was expected due to the higher structural capacity of the mass timber product. Surprisingly, sustainability topics such as carbon emission and life-cycle analysis (LCA) were transversal in all periods with concrete as a recurrent keyword in the analysis. More specialized topics such as robustness, disproportioned collapse, perceptions, and attitude were observed in the final periods. Research projections indicate that for mid-rise and tall timber buildings, the environmental potential has to be aligned with the structural feasibility and perception of the construction’s actors and society to improve the carbon emissions reduction and support the increment of the population in an urban context.
... air-dried lumber, kiln-dried lumber and furniture parts). The eight articles not assessing wood-based panels as the primary product instead address furniture manufacturing (Li et al., 2019), structural frame manufacturing (Lu et al., 2017), utility pole manufacturing (Lu and El Hanandeh, 2016) and waste wood management and wood cascading systems (Faraca et al., 2019;Hoglmeier et al., 2015;Höglmeier et al., 2014;Hossain and Poon, 2018;Kim and Song, 2014). The most assessed panel type is particleboard (analysed in 33 articles). ...
... Eight present other functional units, seven of which do not assess wood-based panels as a primary product. In these cases, the functional units considered are defined by acknowledging the system under assessment, such as a structural frame (Lu et al., 2017), the mass of wood waste (Faraca et al., 2019;Hossain and Poon, 2018;Kim and Song, 2014), one wardrobe (Li et al., 2019), one pole (Lu and El Hanandeh, 2016) and wood volume (Hoglmeier et al., 2015). Eshun et al. (2010) present more than one functional unit to explore the influence of using different functional units. ...
... sawlogs, small-diameter logs, or forest residues). The most common procedure when woodbased products are produced with logs is economic allocation (Diederichs, 2014;Lu and El Hanandeh, 2016;Lu et al., 2017), although massic allocation has also been applied by McDevitt and Grigsby (2014). When wood-based products are produced with forest residues, the most common approach is to consider that they are burden-free (Garcia and Freire, 2014;Gonzalez-Garcia et al., 2009, 2011. ...
... of in landfill), is critical, as they can significantly influence the studied impact categories [146], [153], [156]. The environmental consequences of these end-of-life decisions can be substantial at the building level, accounting for up to 50% of the total life cycle impact of the building [157]. ...
... The environmental consequences of these end-of-life decisions can be substantial at the building level, accounting for up to 50% of the total life cycle impact of the building [157]. For the case of steel frames, recycling can help achieve considerable reductions in the overall environmental impact [153], [156]. Table 3.4 provides a brief overview of how modern wood buildings perform in relation to conventional buildings in terms of different environmental impact categories. ...
... (2) The cumulative energy demand (CED), which is used to determine and compare the energy intensity of processes, appears to be similar or higher with the nonwood counterparts due to the use of a large volume of timber and the associated use of adhesives in the production of EWPs [131], [145], [152], [153]. However, wood buildings consume a far higher proportion of renewable energy than non-renewable energy [136], [145], [152], [154], [155]. ...
... of in landfill), is critical, as they can significantly influence the studied impact categories [146], [153], [156]. The environmental consequences of these end-of-life decisions can be substantial at the building level, accounting for up to 50% of the total life cycle impact of the building [157]. ...
... The environmental consequences of these end-of-life decisions can be substantial at the building level, accounting for up to 50% of the total life cycle impact of the building [157]. For the case of steel frames, recycling can help achieve considerable reductions in the overall environmental impact [153], [156]. Table 3.4 provides a brief overview of how modern wood buildings perform in relation to conventional buildings in terms of different environmental impact categories. ...
... (2) The cumulative energy demand (CED), which is used to determine and compare the energy intensity of processes, appears to be similar or higher with the nonwood counterparts due to the use of a large volume of timber and the associated use of adhesives in the production of EWPs [131], [145], [152], [153]. However, wood buildings consume a far higher proportion of renewable energy than non-renewable energy [136], [145], [152], [154], [155]. ...
... of in landfill), is critical, as they can significantly influence the studied impact categories [146], [153], [156]. The environmental consequences of these end-of-life decisions can be substantial at the building level, accounting for up to 50% of the total life cycle impact of the building [157]. ...
... The environmental consequences of these end-of-life decisions can be substantial at the building level, accounting for up to 50% of the total life cycle impact of the building [157]. For the case of steel frames, recycling can help achieve considerable reductions in the overall environmental impact [153], [156]. Table 3.4 provides a brief overview of how modern wood buildings perform in relation to conventional buildings in terms of different environmental impact categories. ...
... (2) The cumulative energy demand (CED), which is used to determine and compare the energy intensity of processes, appears to be similar or higher with the nonwood counterparts due to the use of a large volume of timber and the associated use of adhesives in the production of EWPs [131], [145], [152], [153]. However, wood buildings consume a far higher proportion of renewable energy than non-renewable energy [136], [145], [152], [154], [155]. ...
This EFI report on wood-based textile fibres and modern wood buildings is based on comparative life cycle assessment (LCA) studies and interviews with experts. The authors present the foreseen technological developments that support the development of wood-based fibres and modern wood buildings towards environmental sustainability. They also provide insight into the limitations to the development of wood-based textile fibres and modern wood buildings.
... Among the first to investigate into this were Buchanan and Honey (1994) who arrived at the conclusion that timber structures for buildings embody far less EE and ECO 2 e than functionally identical structures with reinforced concrete or steel members. Later studies supported this finding (Gustavsson, Pingoud, and Sathre 2006, Gustavsson and Joelsson 2010, Vukotic, Fenner, and Symons 2010, Skullestad, André Bohne, and Lohne 2016, Lu, Hanandeh, and Gilbert 2017, which may be partially attributed to a comparatively lower energy demand for manufacturing of wood-based components. Moreover, ECO 2 e in timber structures may account for the amounts of CO 2 sequestered from the atmosphere during tree growth, see e.g. ...
... Several studies point to a comparatively larger impact of steel structures, what is often attributed to the more energy intensive processes involved in the material manufacturing process as compared to concrete production (Buchanan and Honey 1994, Acree Guggemos and Horvath 2005, Aye et al. 2012, Kim et al. 2013. Conversely, other studies arrived at the opposite conclusion (Jönsson, Björklund, and Tillman 1998, Lu, Hanandeh, and Gilbert 2017, Oladazimi, Mansour, and Hosseinijou 2020, Hawkins et al. 2021). The reasons for this are various. ...
... While in most countries steel production incorporates significant amounts of recycled material, with a corresponding large environmental benefit (Vukotic, Fenner, and Symons 2010, Gan et al. 2017, Hawkins et al. 2021, recycling of concrete waste (e.g. of the aggregates) is not yet standard practice. Not rarely, concrete residues are fully destined to landfill, with a detrimental impact on the ecosystem (Lu, Hanandeh, andGilbert 2017, Oladazimi, Mansour, andHosseinijou 2020). See Section 2.3 for further discussion on material-related influence on ECO 2 e. ...
Engineering structures consume a significant fraction of resources and contribute to greenhouse gas emissions worldwide. A conducted literature review shows that most existing approaches to improve the environmental performance of structures concern the adoption of decisions during the conceptual design stage (e.g. on the choice of material), often in connection with life cycle assessment. However, approaches for addressing environmental objectives in practice are often hampered by economic interests pursuing short-term profit. Moreover, such approaches are rather descriptive and lack criteria for assessing the acceptability of specific solutions. Sustainable development of our built environment requires hence a shift of paradigm on how engineering structures are designed. In this paper it is claimed that this should be approached at the strategical level of structural design codes, which contain the rules that support everyday engineering decisions in regard to structural safety and functionality. The paper discusses the reasons why these rules as conceived do not foster an optimal use of materials and explores possibilities for savings of resources and greenhouse gas emissions through modifications of these rules. The potential of risk-informed decision approaches in this context is highlighted and illustrated by a case study - the design of steel beams in building structures.
... of in landfill), is critical, as they can significantly influence the studied impact categories [146], [153], [156]. The environmental consequences of these end-of-life decisions can be substantial at the building level, accounting for up to 50% of the total life cycle impact of the building [157]. ...
... The environmental consequences of these end-of-life decisions can be substantial at the building level, accounting for up to 50% of the total life cycle impact of the building [157]. For the case of steel frames, recycling can help achieve considerable reductions in the overall environmental impact [153], [156]. Table 3.4 provides a brief overview of how modern wood buildings perform in relation to conventional buildings in terms of different environmental impact categories. ...
... (2) The cumulative energy demand (CED), which is used to determine and compare the energy intensity of processes, appears to be similar or higher with the nonwood counterparts due to the use of a large volume of timber and the associated use of adhesives in the production of EWPs [131], [145], [152], [153]. However, wood buildings consume a far higher proportion of renewable energy than non-renewable energy [136], [145], [152], [154], [155]. ...
Executive summary
WHAT IS AT STAKE?
The production and use of wood-based textile fibres and engineered wood products in buildings have been identified as promising areas for carbon storage and greenhouse gas emission reductions. However, a number of other environmental impacts are reported as potentially being associated with the processing, manufacturing, use and disposal of (wood) products, including eutrophication, acidification, photochemical oxidant formation and human toxicity.
Currently the understanding of these impacts is still limited. To date, there are no systematic studies available that have examined the non-climate environmental impacts that occur throughout the life cycle stages of wood-based textile fibres and modern wood buildings. This study sets out to explore the potential non-climate environmental impacts of wood-based textile fibres and modern wood buildings. Based on comparative life cycle assessment (LCA) studies and interviews with experts, we present the foreseen technological developments that support the development of wood-based fibres and modern wood buildings towards environmental sustainability. We also provide insight into the limitations to the development of wood-based textiles and modern wood buildings.
... [12][13][14][15][16][17]. The prefabrication of wood-based building construction materials, including laminated veneer lumber, GLT, and cross laminated timber, allowed the increased use of timber in the construction sector [18][19][20][21][22][23]. The use of engineered wood products in construction enables the sector to build multi-storey public and commercial buildings, industrial and agricultural halls, bridges, sport centres etc. [12,18,21]. ...
... The prefabrication of wood-based building construction materials, including laminated veneer lumber, GLT, and cross laminated timber, allowed the increased use of timber in the construction sector [18][19][20][21][22][23]. The use of engineered wood products in construction enables the sector to build multi-storey public and commercial buildings, industrial and agricultural halls, bridges, sport centres etc. [12,18,21]. Still, the market share of wood-based constructions in Europe is below 10%; therefore, these materials possess great potential for substituting non-wood building constructions for wood alternatives, and thereby making the construction sector more sustainable [24]. ...
... Therefore, a gradual increase in the share of wood-based construction can significantly contribute to reduced CO 2 emissions in the national construction sector. Wood and wood-based materials have been shown to be environmentally beneficial in the environmental assessment of the full life-cycle of buildings [18,[27][28][29][30]. The use of wood-based construction materials can lead to a lower environmental impact compared with non-wood alternatives [31][32][33]. ...
The European Commission adopted a long-term strategic vision aiming for climate neutrality by 2050. Lithuania ratified the Paris agreement, making a binding commitment to cut its 1990 baseline GHG emissions by 40% in all sectors of its economy by 2030. In Lithuania, the main construction material is cement, even though Lithuania has a strong wood-based industry and abundant timber resources. Despite this, approximately twenty percent of the annual roundwood production from Lithuanian forests is exported, as well as other final wood products that could be used in the local construction sector. To highlight the potential that timber frame construction holds for carbon sequestration efforts, timber and concrete buildings were directly compared and quantified in terms of sustainability across their production value chains. Here the concept of “exemplary buildings” was avoided, instead a “traditional building” design was opted for, and two- and five-floor public buildings were selected. In this study, eleven indicators were selected to compare the sustainability impacts of wood-based and concrete-based construction materials, using a decision support tool ToSIA (a tool for sustainability impact assessment). Findings revealed the potential of glue-laminated timber (GLT) frames as a more sustainable alternative to precast reinforced concrete (PRC) in the construction of public low-rise buildings in Lithuania, and they showed great promise in reducing emissions and increasing the sequestration of CO2. An analysis of environmental and social indicators shows that the replacement of PRC frames with GLT frames in the construction of low-rise public buildings would lead to reduced environmental impacts, alongside a range of positive social impacts.
... Recent studies comparing CLT and reinforced concrete in Australia have shown that the LCC of CLT is 1.3% cheaper than conventional reinforced concrete in mid-rise residential buildings (Jayalath et al., 2020). Lu et al. (2017) also found that the LCC of the concrete frame of apartment buildings was about 10% lower than similar building using steel during the construction stage. Thomas and Ding (2018) adds that material and construction cost make up to 84% of the LCC in residential buildings. ...
... The ISO15686-5 is the LCC standard for the building and construction sector. In Australia and the AS/NZS4536:1999 provides useful guidelines in conducting LCC in buildings (Lu et al., 2017). Nevertheless, the application of LCC in buildings is challenging as the method relies on a wide range of assumptions (Zuo et al., 2017). ...
... The LCC in this study also utilised data based on the project documents, and supplemented information from relevant literature such as Lu et al. (2017) and Jayalath et al. (2020). The system boundaries for the LCC aligns with the LCA conducted in order to achieve consistency (Valdivia et al., 2021). ...
Significant transition in the built environment will require an integrative and holistic application of Life Cycle Sustainability Assessment (LCSA) to accomplish a better understanding of shift in sustainability impacts across building life cycle phases. Nevertheless, there has been considerable difficulty in implementing life cycle sustainability thinking in buildings due to the complexity of harmonising the three dimensions of LCSA. This work, therefore, aims to monetise the key life cycle sustainability impacts of reinforced concrete and cross laminated timber (CLT) on a building project. This research undertakes a LCSA study based on cradle-to-gate system boundary to evaluate two alternative structural systems in an equivalent 5-star GreenStar-rated public infrastructure building project in Victoria, Australia. Hotspot analyses is conducted to ensure that indicators considered in the study represents up to 85% of the key life cycle impacts. Obtained results show that the overall life cycle sustainability impact of the original structural system (1.55 million) in the case study project. Material substitution in building structural systems could provide a viable pathway in achieving net-zero emissions in Australia's built environment. Consequently, there is a compelling case to develop a holistic life cycle sustainability rating tool to enhance integrated design practice, improve resource utilisation and foster transparency in achieving life cycle sustainability in the built environment.
... In the LCA conducted by Nakano et al. [78], the values were 4% and 2%, respectively [84]. When evaluating the environmental impact of transportation based on assumptions, building materials were typically delivered via truck [34,70,77,78], rail [78,85] or sea freight [56] during the P&C and EoL stages. Dolezal et al. [74] quantified the environmental impact of the A4 (shown in Fig. 2) using the default trucks in Eco2Soft based on Ecoinvent. ...
... The assumptions made in EoL vary significantly and will have a strong relationship with the results. CLT, glulam and LVL [85] were extensively investigated for landfills, biomass recovery, and reuse. CLT was assumed to be 50% incinerated and 50% used for biomass energy [45], 55% recycled with 45% used for biomass energy in another study [80], 91% recycled in a subsequent system, 7% used for energy and 2% for landfilling (based on https://ec.europa.eu/eurostat/data/database) ...
... Concrete is routinely crushed into aggregate to replace natural gravel in concrete production or to fill other applications such as road construction [64,66]. Steel is regarded to be recovered and recycled, replaced into feedstock, which replaces ore-based steel for the new steel products, with a rate of 85% in reference [85], and 90% in another study [52]. Additionally, some research referred to regulation and baseline for assessing the EoL stage. ...
Life cycle assessment (LCA) has been widely used to determine the environmental impact of mass timber construction (MTC) as a substitute for conventional construction. This article presents a systematic review of MTC from a life cycle assessment perspective. The goal and scope definition, life cycle inventory analysis, impact assessment and interpretation are examined and analyzed in 62 peer-reviewed articles. The results show the variety in scope, lifespan, system boundary, data sources and indicators. Studies on MTC have been conducted at the building material, component, structure, and entire building levels, as well as at the urban level. The majority of studies compare the LCA of reinforced concrete (RC) and cross laminated timber (CLT) buildings. The global warming potential (GWP) and life cycle energy are the most frequently evaluated category indicators among the articles. It is found that the average embodied energy of mass timber buildings is 23.00% higher than that of RC alternatives, while the average embodied greenhouse gas (GHG) emissions of RC buildings are 42.68% higher than that of mass timber alternatives. There is a clear general trend that mass timber buildings generally have lower GWP and life cycle primary energy (LCPE) than RC and steel buildings. Eventually, sensitivity analysis, carbon storage and outlook of the mass timber are also reviewed and discussed in the literature.
... Despite the high number of publications and recent developments in the standardization of LCA and LCC, very few studies mention any standards as a basis for their calculations. For the LCA process, ISO 14040, ISO 14044, the building-specific EN 15978, or the building-product-specific EN 15804 are referred to [6,8,52,56,57,59,62,63,65,66,72]. Only three studies refer to an LCC standard; two Australian studies [52,56] refer to AS/NZS 4536, while one European study [62] refers to EN 15686-5. ...
... For the LCA process, ISO 14040, ISO 14044, the building-specific EN 15978, or the building-product-specific EN 15804 are referred to [6,8,52,56,57,59,62,63,65,66,72]. Only three studies refer to an LCC standard; two Australian studies [52,56] refer to AS/NZS 4536, while one European study [62] refers to EN 15686-5. Moreover, underlying calculation metrics were rarely clearly described and are often missing altogether, making results difficult to interpret. ...
... Conci et al. [45] assume a linear decrease in electricity mix emissions over time and a 30% increase in manufacturing efficiency over the next 100 years. Two studies apply discounting to environmental impacts after converting them to monetary values: for GWP only [56], or for a set of indicators [70]. One study considers a price increase for GWP [53]. ...
With increasing environmental damage and decreasing resource availability, sustainability assessment in the building sector is gaining momentum. A literature review shows that the related methods for environmental and economic performance, Life Cycle Assessment (LCA) and Life Cycle Costing (LCC), show great potential for answering a multitude of questions related to building performance. Prevalent topics are the implications of LCA and LCC for retrofit solutions and the trade-offs between environmental and economic considerations in building design. A detailed review of 30 case studies shows the range of differing result integration methods and sheds light on the use of monetary valuation of environmental indicators for an integrated assessment. While a quasi-dynamic approach, accounting for the changing value of money over time, is common in LCC, such an approach is largely absent from LCA. The analysis of common metrics shows that the studies employ strongly differing system boundaries and input parameters. Moreover, a clear description of the methodological framework is missing in most studies. Therefore, this research develops an “Eco²” framework, integrating LCA and LCC for application in building design. Potential further developments for Eco² building assessment are related to extending the system boundaries by including mechanical systems and end-of-life phases, data collection and structuring, and streamlining the approach for continuous application to all stages of building design processes. Additionally, the influence on design decisions of employing temporal parameters in both LCA and LCC and of choosing particular result integration methods should be investigated further.
... Surprisingly, most of this research considered CLT, giving it more attention than other Mass timber products (17 publications out of 21 considered CLT). Most of the studies that considered both LCA and LCC elected the "entire building" as their functional unit (Lu et al., 2017b). A few studies considered entire buildings when only LCA was evaluated (Salgado & Guner, 2021). ...
... The majority of studies compared an Mass timber with concrete and steel. For example, Lu et al. (2017b) claimed that LVL had the lowest LCC ($128,855), which were less than a quarter of the concrete option ($498,698) and almost half the cost of steel buildings ($210,678) in Australia. Mass timber buildings have a lower GWP than concrete and steel buildings. ...
Life cycle analysis has been used to evaluate the environmental impacts and economic costs of a range of engineered timber structural materials as well as other materials such as steel and concrete over the last two decades. This study presents a bibliometric analysis and systematic critical review by investigating the life cycle sustainability assessment (LCSA) of engineered timber products. LCSA is comprised of three main pillars namely, environment, cost, and social impact. The study compares alternative engineering wood products used in building structures such as columns, beams and wall surfaces. The geographical distribution, main sources of research, co-occurrence of keywords were analyzed for 93 peer-reviewed articles and conferences. The United States was the most productive country, contributing almost 23 documents. Australia was next with 12 publications. Most studies compared the LCA and LCC of alternative Mass timber products and concrete or steel. Most studies evaluated cross laminated timber (62%), followed by glued laminated timber (17%), and laminated veneer lumber (9%). A comparison of the economic and environmental aspects indicated that the social aspect are less considered. The review showed that the global warming potential of manufactring1 M³ of cross laminated timber is about 155.6–158.6 kg CO2eq. The majority of the publications reviewed focused on LCA whilst others focussed on the LCC of Mass timber. No research on social life cycle assessment has been conducted as yet. A framework is suggested for future research to identify the best alternative for engineering wood.
... Furthermore, we observed two studies that combined sensitivity and scenario analysis (Churchill and Panesar 2013;Edwards et al. 2018). Whereas six studies jointly performed the sensitivity analysis with the Monte Carlo simulation (Kendall et al. 2008a;Lu and El Hanandeh 2017a, b;Lu et al. 2017;Gunkaya 2020;Loannidou et al. 2022). ...
... (a) Uncertainties in cost data (Kendall et al. 2008a;Zhang et al. 2010;Mousazadeh et al. 2011;Hardisty et al. 2011;Yu et al. 2013;Simoes et al. 2013;Debacker et al. 2013;Simoes et al. 2014;Martinez-Sanchez et al. 2015;Wu et al. 2015;Weldu and Assefa 2017;Lu and El Hanandeh 2017a, b;Man et al. 2017;Lu et al. 2017;Hall et al. 2017;Lee and Thomas 2017;Edwards et al. 2018;Albuquerque et al. 2019;Shi et al. 2019;Hong et al. 2019;Ma et al. 2019;Zhang et al. 2020a;Liu et al. 2020;Stipanovic et al. 2020;Wang et al. 2020;Gulcimen et al. 2021;Canaj et al. 2021;Marin and Lang 2022;Trovato and Cappello 2022;Yao et al. 2022) (b) Lack of methodological clarity on the monetization of external costs (Kendall et al. 2008a;Wu et al. 2015;Martinez-Sanchez et al. 2016;Corona et al. 2016;Luttenberger and Luttenberger 2017;Hall et al. 2017;Lee and Thomas 2017;Edwards et al. 2018;Liu et al. 2021;Caramanico et al. 2021) (c) Limited perspective, based only on local data (Kim et al. 2011;Settembre et al. 2018;Liu et al. 2020;Zhou et al. 2021) (d) Lack of connection between data as a local reality experienced in the product system Zhang et al. 2020a;Li et al. 2020) In addition to these categorized challenges, some examples of individual difficulties identified in the studies are cited: i) personal subjectivity and limitations in assessing external costs (Lim et al. 2013); ii) the use of temporary values for some impacts (e.g., biodiversity related to land use) that must be replaced (Chen and Holden 2018); and iii) the complexity to obtain data for inventories with their respective collection method (Nasab et al. 2022). ...
Purpose
In order to train new professionals and researchers in the area, among other purposes, it is necessary to have knowledge about the operationalization of life cycle tools. The objective of this study is to formulate a proposal for conducting environmental life cycle costing (ELCC) from the approach of this content in the scientific literature.
Methods
To this end, we developed a review with the analysis of studies that performed the tool in various productive contexts, between 2008 and 2022, published in journals indexed in the Web of Science. The application of keywords defined for the search allowed the retrieval of 4007 documents. Non-peer-reviewed journal articles, conference papers, review articles, editorial materials, meeting abstracts, letters, and book chapters were excluded. The abstracts and methodologies were also read to further exclude articles that were not classified using the ELCC. With the application of these procedures, we obtained 133 articles, which were analyzed in detail.
Results and discussion
A proposal for conducting the ELCC was formulated to guide the execution of the tool. This was composed of procedures, challenges, and opportunities. The main procedures identified included the delimitation of a perspective, goal, scope, internal and external cost categories, application of economic indicators, and uncertainty analysis. The main identified challenges refer to the ELCC execution reproducibility, the difficulty in standardizing cost categories, and the limited vision regarding the tool use. The opportunities mapped out encompass the exploration of the thirty-two gaps pointed out for ten research segments, emphasis on the service sector, government programs, creation of databases, and approach to ELCC concepts in educational training.
Conclusions and recommendations
The proposal made it possible to systematize knowledge from the way ELCC has been conducted in the last decades in different segments. In the practical field, this study serves to guide researchers, professionals, or students who wish to use the tool to achieve professional goals. Future research can also refine and explore the proposed structure, as well as the identified gaps and other opportunities.
... Furthermore, buildings made of CLT typically demonstrate superior energy savings than comparable concrete structures [3]. Malle and Espinoza [4] illustrate cost saving potential when using structures , mass transfer coefficient for water vapor during the wetting phase (m s −1 ) heat transfer coefficient for water vapor (W m −2 K −1 ) capillary pressure (Pa) gas pressure (Pa) temperature (K) made of CLT instead of concrete, and Lu et al. [5] show that life cycle costs of laminated veneer lumber can be lower compared to concrete and steel, respectively, making CLT an excellent alternative to conventional building materials. ...
... Additionally, an evaluation of the performance of MAE and RMSE for all configurations (see Figs. [5][6][7][8] shows an adequate correlation for S 60 (MAE ranging from 0.75 to 1.33 and RMSE from 1.09 to 1.48) and S 90 (MAE from 0.81 to 1.80 and RMSE from 0.99 to 1.92). There is also a sufficient replication quality for M 90 (MAE from 1.14 to 1.92 and RMSE from 1.31 to 2.22). ...
... However, the scope of LCA is mainly limited to comparative studies of different decision alternatives on the level of particular buildings or parts of them, see e.g. [14][15][16][17][18]. When widening the scope from a building to the scale of a country, or region, dynamic material flow analysis (MFA) is a well-suited method to determine the time-dependent material flows and stocks of the built environment and their associated environmental impact [19]. ...
... The other possibility is the substitution by different materials. Several studies have identified clear environmental benefits of timber in comparison to other structural materials [16,30,[73][74][75][76]. The present study explores the substitution of masonry structures (MS) by timber structures (TS). ...
Embodied emissions in construction materials make a relevant contribution to carbon emissions worldwide. While this has been broadly recognised, only little attention has been paid to the role of load-bearing structures in this regard, and if so, mainly limited to assessments of individual structures. For analysing the global warming impact of engineering structures in a wider context, dynamic material flow analysis is deployed in this study. The future stocks and flows of structural materials and their associated embodied emissions in German residential buildings are quantified based on a mass-balance consistent multi-layer model, which relates the stocks in use, their inputs, outputs and determinants, such as the building lifetime, the population or the useful building floor area per capita. A scenario analysis under combination of different emission mitigation measures is performed, among them a gradual replacement of the comparatively large masonry structure stock share by timber structures, and a general downsizing of structural material quantities. The results show that when applied to a realistic extent, such measures could contribute with about 4% to 8% to the German average target mitigation rate required for achieving emission neutrality in 2045.
... Other research has focused on LVL as a building material. For instance, Lu et al. (2017a) used LCA to study LVL, steel, and concrete. Their results showed that LVL performed better than steel and concrete as a structural material. ...
... Nevertheless, there are no studies that identify the differences between GLT and LVL. Most studies compare different mass timber materials such as LVL and GLT with alternatives (such as steel and concrete) to highlight mass timber as the best choice with a lower environmental impact (Lu et al. 2017a;Andersen et al. 2022;Chen et al. 2022b;Teh et al., 2017). Other research is not comprehensive, being limited to embodied energy (Ramage et al. 2017). ...
The embodied carbon of building materials and the energy consumed during construction have a significant impact on the environmental credentials of buildings. The structural systems of a building present opportunities to reduce environmental emissions and energy. In this regard, mass timber materials have considerable potential as sustainable materials over other alternatives such as steel and concrete. The aim of this investigation was to compare the environment impact, energy consumption, and life cycle cost (LCC) of different wood-based materials in identical single-story residential buildings. The materials compared are laminated veneer lumber (LVL) and glued laminated timber (GLT). GLT has less global warming potential (GWP), ozone layer depletion (OLD), and land use (LU), respectively, by 29%, 37%, and 35% than LVL. Conversely, LVL generally has lower terrestrial acidification potential (TAP), human toxicity potential (HTP), and fossil depletion potential (FDP), respectively, by 30%, 17%, and 27%. The comparative outcomes revealed that using LVL reduces embodied energy by 41%. To identify which of these materials is the best alternative, various environmental categories, embodied energy, and cost criteria require further analysis. Therefore, the multi-criteria decision-making (MCDM) method has been applied to enable robust decision-making. The outcome showed that LVL manufacturing using softwood presents the most sustainable choice. These research findings contribute to the body of knowledge about the use of mass timber in construction.
... The results of that study identified problems in the application of LCC methodology in UA such as the frequent not inclusion of essential costs such as operational labour and infrastructure intro the cost calculation. According to Lu et al. (2017), the exclusion of the labour identified as the most significant operation cost and an important production factor (Baumgartner and Belevi, 2001) was the main reason for the incomplete LCC analysis in many UA studies (Lu et al., 2017). Regarding, the infrastructure cost (e.g., greenhouse structure), its inclusion in the LCC is crucial for future development of UA in cities, especially for boost the implementation of innovative environmentally friendly UA systems on a large scale. ...
... The results of that study identified problems in the application of LCC methodology in UA such as the frequent not inclusion of essential costs such as operational labour and infrastructure intro the cost calculation. According to Lu et al. (2017), the exclusion of the labour identified as the most significant operation cost and an important production factor (Baumgartner and Belevi, 2001) was the main reason for the incomplete LCC analysis in many UA studies (Lu et al., 2017). Regarding, the infrastructure cost (e.g., greenhouse structure), its inclusion in the LCC is crucial for future development of UA in cities, especially for boost the implementation of innovative environmentally friendly UA systems on a large scale. ...
The construction of innovative urban agriculture systems in cities has increased due to food and environmental concerns. While the environmental performance of urban agriculture has been extensively studied, research on the life cycle costs urban agriculture systems is still limited, which constraints sustainability-oriented decision-making processes. This paper analyses the economic viability of tomato production cycle in an innovative building with an integrated urban agriculture system in rooftop by applying the life cycle cost methodology. The data was collected from direct measurements and internal and external sources. To calculate labour costs, a customised data collection sheet was created. The results are presented by life cycle stage, cost category and type of cost (fixed & variable). Results indicate that the main cost drivers for tomato production are labour (24.7%), the rooftop greenhouse structure (15%), the external pest control (12.6%), and rainwater consumption (9.5%), accounting altogether for 61.8% of the total costs. Accordingly, cost reduction solutions are evaluated through the development of sensitivity scenarios (rooftop greenhouse structure design, tap water use and rainwater tank size), including the consideration of another relevant aspect, such as the role of the production level output, as it can greatly influence the economic viability and profitability. Finally, the main environmental and social aspects of these urban production systems are also included.
... Materials with a high residual value because of their scarcity or energy-intensive production, such as metals, should also receive financial credits in LCC. However, these credits (e.g., for scrap metal) can be very small compared to investment cost [33], and they happen in the distant future. Moreover, in the databases used for this study, disposal costs include potential material values but do not consider them separately, i.e., if there are economic benefits for phase D, they are merged with the demolition and disposal cost. ...
... In all scenarios, the inclusion or exclusion of end-of-life credits has a significant impact, especially on options with large amounts of wood or metals. This is in line with results from the literature suggesting that wood and steel options are more sensitive towards changes in discount rates due to significant credits in the end-of-life phases [33]. ...
The architecture, engineering and construction (AEC) sector has great potential and responsibility for reducing its considerable resource consumption and high share of global emissions. However, economic factors are often cited as barriers to more environmentally friendly solutions in building design. Hence, environmental and economic life cycle assessment (LCA and LCC) are of utmost importance in building design. They serve as the base methodologies for what we call the “Eco²” framework. In this context, monetary valuation of multiple environmental impacts allows to integrate the results as a basis for design decisions. A case study representative of small-scale office buildings in Germany illustrates the Eco² framework and shows the influence of temporal parameters (discount rates and price changes), as well as of differing monetary valuation, on the ranking of design options. Varying the temporal parameters affects the ranking of different solutions for the structure and finishes of the case study building but not for its mechanical, electrical and plumbing (MEP) systems and operation. However, the ratio of environmental life cycle cost (eLCC) to financial life cycle cost (fLCC) is significantly higher for MEP systems and operation than for the structure and finishes. This investigation shows that it is possible to achieve simultaneous emission and cost savings, whereas temporal factors can decisively influence decision making in design processes.
... Sustainable construction 3 [101], [102], [103]. Value engineering 35 [104], [105], [106], [107], [108], [109], [110], [111], [112], [113], [114], [115], [116], [117], [118], [119], [120], [121], [122], [123], [124], [125], [126], [127], [128], [129], [130], [131], [132], [133], [134], [135], [136], [137], [138]. Table 3 shows the distribution of industrial engineering modules whose descriptions aligned with the 18 relevant principles and methodologies previously identified in this paper. ...
The construction industry is embracing sustainable practices to combat environmental degradation and climate change, and engineered wood products (EWPs) offer promise as structural materials for sustainable infrastructure. Despite the benefits of EWPs, challenges such as supply chain integration and market acceptance have limited their use. This paper explores how industrial engineering could facilitate the adoption of EWPs in the South African construction industry, and provides a framework for developing critical industrial engineering capabilities that the South African timber construction sector should possess to integrate EWPs efficiently into construction projects. We used a comprehensive literature review and a curriculum analysis to achieve the study’s objectives. By drawing upon these capabilities, the study identified where industrial engineering as an expertise could drive innovation adoption.
... Third, the non-uniformity of features assembled in the database, which makes it hard to compare and combine them [31,32]. Research in this category focuses mostly on predicting energy use [33][34][35][36][37][38], energy performance [39][40][41][42] and on whole life or operational carbon emissions [43][44][45][46][47]. Research addressing embodied GHG emissions is limited to smallscale statistical studies [48][49][50][51][52][53][54][55] or basic linear regression [56,57]. This research presents a ML method which can be trained on databases of existing buildings to predict the embodied GHG emissions of new projects from a small input set of features easily accessible at early design stages. ...
... In this regard, this study compares the existing typical concrete residential buildings with the equivalent MTC alternatives in terms of economic assessment comprising of LCCA and the environmental assessment of embodied impacts of energy and CO2 emissions. While recent studies have investigated LCA and LCCA in mass timber and other building types [2,[21][22][23], greater efforts are required to fully understand the environmental and economic impacts of mass timber buildings [2]. Moreover, this work explicitly sets a precedent to compare the environmental and economic performance of mass timber buildings with the existing concrete ones in the Bhutanese context. ...
... Sensitivity analyses, which are based on the premise of carefully specifying the range of uncertainty or the selection of a distribution function, test the reliability of model assumptions and data for evaluating outcomes [45]. Lu investigated the environmental impacts of the entire structural framework of a residential apartment based on the life cycle theory, which performs a local sensitivity analysis of the multi-influence factors (variations between −10% and +10%) and an environmental performance analysis with uncertainty based on a Monte Carlo simulation [46]. The sensitivity analysis was undertaken by introducing a 20% increase in the dominant distinguished parameters to measure the environmental and economic assessment results of the life cycle CO 2 [47]. ...
With the intensification of climate warming, the carbon dioxide emissions from high-energy-consuming elevators have attracted increasing societal attention. The assessment of carbon dioxide emissions, particularly the boundaries and strategies of carbon dioxide emissions accounting, lacks systematic research. However, an efficient evaluation of elevator carbon dioxide emissions is beneficial for improving elevator energy utilization. A carbon dioxide emissions accounting method and inventory analysis of a life cycle for an elevator is proposed to measure the carbon dioxide emissions from production to disposal. In addition, a new assessment indicator, namely, annual carbon dioxide emissions per ton·kilometer, is proposed to evaluate the carbon dioxide emissions for different types of elevators. The lifetime carbon dioxide emissions of the elevator and its sensitivity to influencing factors were assessed. The results indicate that the carbon dioxide emissions in the four stages of manufacturing, installation, operation and maintenance, and demolition and scraping contributed 41.31%, 0.92%, 57.32% and 0.44%, respectively. The annual carbon dioxide emissions of the elevator were about 27.18 kgCO2/t·km. The four primary factors affecting CO2 emissions were electricity consumption, printed circuit boards, low-alloy steel and chrome steel in descending order. Their probability distribution characteristics all obeyed triangular or uniform distributions. The median of their 95% confidence intervals was about 73,800. Their coefficients of variation were all below 2.1%. The effective strategies for energy conservation and carbon reduction were suggested by the life cycle impactor assessment. They also provide guidance for sustainable elevators.
... Basaglia et al. [12] compared the LCA of three materials (GLT, CLT, and concrete) and showed that the embodied energy of CLT is almost 2.5 times higher than that of concrete. Lu et al. [13] sowed that emissions of engineered wood in the environmental categories of greenhouse gas, acidification, human toxicity, and fission depletion are all low compared to concrete and steel for multi-storey residential buildings. Jayalath et al. [14] assessed the environmental impact of high-rise residential buildings in CLT and showed that the carbon dioxide emissions were reduced by up to 34% compared with reinforced concrete residential buildings. ...
... In addition, the new European Bauhaus initiative will provide support for innovative projects in wood construction. Engineered wood products (EWP's) such as glued laminated timber (GLT), laminated veneer lumber (LVL) and cross laminated timber (CLT) have allowed for an increased use of wood in large scale construction (Hurmekoski et al., 2015, Lu et al., 2017Ilgın et al., 2021). Given that the market share of wood-based construction in Europe is below 10% (Hildebrandt et al., 2017), there is great Table 1 Available datasets for wood for construction in new dwellings in 2017-2021 across the 30 European countries studied (see also Appendix B for the corresponding data). ...
Wood is an energy efficient, low carbon construction material that if carefully managed can contribute significantly to European climate policy goals in urban environments. The aim of this study is to assess the current construction wood use intensity ─ the ratio of apparent national consumption of wood for construction (in m3) to the useful floor area of newly finished dwellings (in m2) ─ and to identify when and where additional policy measures are required. Results show that Cyprus/Malta have the smallest use with a ratio of 0.01, Estonia/Romania the greatest use with a ratio of 0.32. The need for additional policy measures, was assessed using the Boston Consultancy Group (BCG) matrix with four product development phases, based on the aforementioned ratio versus future growth. Six, twelve, eight and two countries are in the “Introduction“, “Growth”, ”Maturity” and “Decline” phases, respectively. The inventory also covers the use of other biobased materials, like flax, hemp and miscanthus, for insulation purposes.
At the EU level, the European Commission should consider introducing a Renewable Material Directive, in which a Non-biogenic Material Comparator shows the average GHG substitution effect of using wood for construction. At the international level, a new harvested wood product (HWP) category in the IPCC Guidelines is recommended for construction wood with a longer lifespan than the current HWP categories.
... Délka životního cyklu je tak zvolena variantně na období 50 a 60 let. Shodnou délku životního cyklu budov zvolili autoři dalších studií: Dwaikat et al [11], H. Lu et al [16], Aktas et al [17], Islam et al [18]. ...
... Wood is a natural and renewable material. Hence, increasing its use within the construction industry could help in the ongoing campaign to reduce the greenhouse gases produced by the construction sector (Thornley et al., 2015;Riffat et al., 2016;Lu et al., 2017;Hart and Pomponi, 2020). In relation to this, several actions are being set up to encourage and promote the use of wood in the construction industry. ...
In recent years, there has been an increasing interest of engineers and architects in the use of timber in the construction sector. This worldwide trend can be mainly attributed to the reduced environmental impact of building with timber, its high strength-to-weight ratio and its renewable material nature. Nevertheless, in spite of the advantages of building with timber, one of its major disadvantages is its time-dependent structural response. For instance, typical floors and beams made of timber may show decreasing stress levels under constant deformation over time. This phenomenon is known as stress relaxation and can also be affected heavily by environmental factors, such as temperature and moisture changes. This has inevitably led to discourage the use of timber in the construction industry. Due to the relevance of this subject, the present paper addresses the stress relaxation phenomenon in timber specimens subjected to three-point bending loads. In particular, radiata pine species is chosen for this investigation given its popularity as a building material in countries like Australia, Chile, Spain and New Zealand, among others. To investigate experimentally the influence of temperature and relative humidity on the stress relaxation at different deformation states, an environmental chamber was built. The stress relaxation is assessed indirectly by monitoring the relaxation of the load required to maintain the amount of deformation fixed in time inside the environmental test chamber. The experimental results show that within a period of 7 days, the percentage of load relaxation may reach a value of 35% approximately, for a fixed relative humidity of 60% and constant temperature of 27∘C{27}\,^{\circ }\hbox {C}. The present experimental results provide further insight into the time-dependent mechanisms of timber which are still not well-understood, and particularly of those structures made of radiata pine grown in Chile on which only limited experimental data has been reported to date.
... However, problems can include: (1) it is not clear how these critical variables are identified; and (2) result shows the variables may not be critical, impeding a better understanding of the uncertainty. A case is, in Lu et al.'s study [107], three variables (change between − 10% and +10) were presumably selected to check their uncertainties, and emissions from transportation processes was tested to be insensitive. In comparison, a hotspot analysis was undertaken by Wang et al. [108] to search the significant variables (i.e., transportation) and then calculated its variability. ...
Environmental impacts (EIs) of building stocks have been receiving significant attention in recent decades as they consume more than 40% of the world's energy, release one third of total greenhouse gas emissions, and account for 30% of global landfill waste. Prior efforts have focused on mitigating EIs during the operation stage of buildings, while the environmental performance of other stages is relatively overlooked. Addressing this, whole-building life cycle assessment (WBLCA) has gained prominence from a life-cycle perspective to ensure the best environmental performance. However, there is an array of factors that can affect WBLCA results, and such uncertainties render decisions made for sustainable development untenable. Aiming to understand the comprehensive uncertain sources of WBLCA (what) and their corresponding solutions (how), this paper systematically reviews existing publications on WBLCA, presents its status and challenges, and analyses the taxonomy of uncertainties and eight uncertainty methods and variants thereof. Accordingly, a framework is developed that enables LCA practitioners to readily understand the correlation between WBLCA uncertainties and solutions, and conveniently locate and appraise them throughout the WBLCA process. Upon answering the known-what and known-how questions, this study contributes to the body of knowledge of LCA by providing a comprehensive and systematic methodology to evaluate the EIs of buildings.
... At the project level, the research on construction carbon emission reduction management mainly focuses on the measurement calculation method of construction carbon emission and collaborative emission reduction management. Carbon emission measurement and collaborative management of carbon emission reduction are carried out for different life cycle stages of buildings [27], building materials [28], building components and parts [29,30], building structure forms [31], etc., to provide reference for low-carbon building design and whole life cycle management. At the regional level, the research on construction carbon emission has mainly focused on the calculation of construction carbon emission and the study of influencing factors. ...
To explore the spatial network structure characteristics and driving effects of carbon emission intensity in China's construction industry, the investigation combined the modified gravity model and social network analysis method to deeply analyze the spatially associated network structure characteristics and driving effects of carbon emission intensity in China's construction industry, based on the measurement of carbon emission data of China's construction industry from 2006 to 2017. The results show that the regional differences of carbon emission of construction industry are significant, and the carbon emission intensity of construction industry show a fluctuation trend. The overall network of carbon emission intensity shows an obvious “core-edge” state, the hierarchical network structure is gradually broken. Economically developed provinces generally play a leading role in the network, and play an intermediary role to guide other provinces to develop together with them. Among the network blocks, most of the blocks play the role of “brokers”. The block with the leading economic development has a strong influence on the other blocks. The increase of network density, the decrease of network hierarchy and network efficiency will reduce the construction carbon emission intensity.
... Their results revealed that wooden houses have greater performance than concrete and steel houses in terms of embodied energy and GWP. They also showed that steel and concrete had the largest environmental burden in all impact categories in construction phase (Lu et al. 2017). In a study, a life cycle energy assessment was applied on a multi-storey residential building and they showed that steel (39.2%), cement (17.9%), aluminum (13.8%) and concrete (9.2%) are the major contributors of the life cycle energy in construction phase (Mehta et al. 2017). ...
In recent years, there has been a significant transition from multi-storey buildings to single-family houses especially due to COVID-19 pandemic. Thus, people prefer to live in single-family houses or detached houses where they have more free space in outside of the house. The aim of this study is to quantify and compare the environmental performance of a single-family house and multi-storey apartment building in Turkey throughout their life cycle with cradle-to-grave approach. Life Cycle Assessment (LCA) based on ISO 14040 and ISO 14044 was used to analyse the environmental impacts of the single-family house and multi-storey apartment buildings. The functional unit was chosen as 1m ² of floor area of a house over their lifespan (50 years). With cradle-to-grave approach of the LCA, the system boundaries for the environmental assessment covers the pre-operation, operation and post-operation stages. The results of this LCA study revealed that majority of the environmental impacts occurs at operation phase for both single-family house and multi-storey apartment. The operation stage has the highest impact with 79% and 78% share of the global warming potential (GWP) for single-family house and the multi-storey apartment, respectively. In comparison of environmental impact results, GWP of the multi-storey apartment per m ² of floor area is 30% lower than single-family house. The environmental impacts of the operation phase have significant importance on the overall environmental performance of both single-family house and multi-storey apartment. The results showed that electricity consumption and steel usage are the main contributors of the environmental impacts coming from the operation and pre-operation phases, respectively. To pave the way to a sustainable future, the building industry must strive to use of renewable energy sources and sustainable construction materials in order to reduce their environmental impacts with a sustainable approach.
This study presents a comprehensive comparative analysis of seismic resilience and sustainability between steel and reinforced concrete structures. With growing demand for environmentally responsible and disaster-resilient infrastructure, evaluating the life cycle performance of construction materials has become critical. Three building typologies—10-, 20-, and 30-story residential structures—are analyzed using a life cycle assessment (LCA), life cycle costing (LCC), and incremental dynamic analysis (IDA) to assess environmental, economic, and seismic performance. The results reveal that reinforced concrete structures tend to exert greater environmental impacts, particularly in categories such as carcinogenic emissions, ecotoxicity, and acidification, primarily due to cement production. Steel structures, while associated with higher energy consumption and mineral resource depletion, demonstrated superior seismic performance across all building heights, characterized by a greater level of ductility and collapse capacity. For instance, the 30-story reinforced concrete structure generated approximately 6.93 million kg CO2 eq, compared to 6.79 million kg CO2 eq for its steel counterpart. Steel structures, while associated with higher energy consumption and mineral resource depletion, demonstrated superior seismic performance across all building heights, sustaining up to a 15% greater spectral acceleration before collapse. Additionally, the LCC analysis showed that reinforced concrete is more cost-effective in high-rise construction, especially during the construction stage. These findings offer valuable insights for engineers and decision makers aiming to balance sustainability and structural performance in urban development.
The construction industry is a major contributor to Greenhouse Gas (GHG) emissions, highlighting the need for more sustainable building practices. While building costs often drive project decision-making, environmental impacts from material production to building operation are considered equally significant. Wood has emerged as a viable alternative to traditional construction materials, offering reduced carbon emissions and potential cost savings. This study aims to assess the environmental and economic performance of a wooden-framed educational building in Finland, with a focus on life-cycle carbon emissions and cost-effectiveness. The case building is a single-story structure with glulam external walls, beams, and columns. A Life Cycle Assessment (LCA) and cost analysis has been conducted using LCA tools provided by the Finnish Ministry of Environment, alongside a comparative scenario analysis involving alternative structural materials. Three alternative scenarios have been designed with different materials utilized for external walls and the structure, i.e., beams and columns. The findings reveal that wood-based structures can achieve substantial reductions in carbon emissions while remaining cost-competitive, particularly in early life-cycle stages compared to conventional reinforced concrete options. The results of this study partially challenge the widely recognized barrier to adopting greener building practices, namely the incremental cost of sustainable construction. Additionally, scenario analysis highlights the potential for hybrid structural systems to balance environmental benefits with economic feasibility. This research contributes practical insights into how contractors and policymakers can adopt wood and hybrid materials to support low-carbon construction goals.
Constructing high-rise buildings using timber has been suggested as a strategy to reduce the construction sector’s carbon footprint. Various studies have already investigated the differences in the global warming potential of a multi-story building when it is redesigned in timber. This study performs a meta-analysis of the existing literature concerning the potential reductions in GHG (greenhouse gas) emissions achieved by timber high-rises. For this, 42 comparative life cycle assessments and additional relevant literature were collected through an online search. The parameters used are the GWP (global warming potential) and the operational energy consumption per unit of area. This was investigated both for the different life phases as well as for the full lifecycle. The outcome was unanimous: for all the studies that included all life phases, the timber variant of the multi-story building caused the least carbon emissions. The reduction in GWP between the concrete and timber benchmark of the building ranged from 2,69% to 677,61%. Between steel and timber, the GWP reduction varied between 1,20% - 144,11%. This wide range in results is attributed to the diversity of considered parameters in an LCA, each of which can have different assumptions and scenarios applied.
Climate change is an important problem that needs to be addressed in this present time. In late 2015, the United Nations held the Sustainable Development summit where 193 countries came together to develop and afterwards agree to uphold the 17 Sustainable Development Goals. The objective of this research is to critically analyse what engineers are able to do within their profession to achieve SDG 13 Climate action. This paper is one part of a broader project investigating the following three research questions: 1. What progress has Australia made against the indicators for SDG 13: Climate action? 2. What role has the Australian engineering sector played in contributing to and mitigating climate change? 3. What role can the Australian engineering sector play in addressing climate change? These questions will be explored by reviewing: • Statistical measures against the SDG13 targets and indicators • Research literature on different technologies and approaches the Australian engineering sector can pursue to further contribute to climate action This paper focuses on the latter point, by reporting a systematic review of the research literature using search terms such as 'climat*', 'engineer*' and 'Australia*' to comprehensively identify relevant publications. In this paper, we describe our methodology, final set of research papers, and preliminary analysis. We will report the key findings and recommendations for different strategies that the engineering sector can use to effectively address climate change at the conference in November.
Capital and property have been combined since Karl Marx wrote Das Kapital in 1867. Indeed, capitalism and the housing market are interlinked because property is an asset whose indexed value upholds global markets. On the other side of property as real estate is the environmental damage and augmentation of climate change that housing represents - mostly in advanced, technological societies. This paper attends to capital investment in housing as the Capitalocene and subsequently through environmental education according to environmental and social principles (social ecology). This article examines what is offered in the Australian curriculum for pre-tertiary and university students in terms of sustainable housing and uses the latest in sustainable housing research and practice to provide a new, visionary basis for environmental education, that tackles housing through 3D printing. The current Australian curriculum on sustainable housing centers on the ‘Illawarra Flame’ house (University of Wollongong), that presents a retrofitting solution to improve the quality of life of the occupants. Illawarra Flame house is a net-zero, energy efficient, solar powered house which provides the tenants with thermal comfort. This article expands and updates the data on sustainable housing from the ‘Illawarra Flame’ house to 3D printing and applies the principles of social ecology to make a link with environmental education that deals with the Capitalocene by offering affordable and sustainable housing.
In this report, WRI researchers explore how rising demand for food, wood and shelter is squeezing land that’s needed for storing carbon and protecting biodiversity. This research uses new modeling to give a true global picture of the carbon opportunity costs for land use and proposes a four-pronged approach–produce, protect, reduce, restore–for sustainably managing the world’s finite land.
The growing demand for energy-efficient and environmentally sustainable building materials has led to an increasing interest in hybrid timber-concrete construction. These structures combine the advantages of the two materials, potentially reducing the carbon footprint, shortening construction timelines, and improving seismic and building physics performance. Herein the structural and environmental performance of ten-story timber-concrete hybrid and a pure concrete building, designed for the Guizhou Province, China, were compared. The structural analysis revealed a significant reduction in the self-weight and base shear of the hybrid structure. The life-cycle analysis demonstrated that the hybrid building outperformed the concrete building in six categories, including global warming potential, acidification potential, human health particulate, eutrophication potential, ozone depletion potential, and photochemical ozone formation potential. Notably, the hybrid building exhibited nearly 65% lower emissions in terms of global warming potential. Moreover, the inclusion of wood components offered the added benefit of carbon storage throughout their lifespan. These findings provide compelling support for the development and implementation of high-rise timber-based hybrid buildings in China. The advantages observed in both structural and environmental aspects encourage the adoption of this innovative construction approach, contributing to sustainable and eco-friendly building practices.
Medium-density fibreboards (MDFs) and particleboards are engineered woods well-known for durability and structural strength. Wood shavings or discarded wooden products can be used for MDF and particleboard production. However, engineered woods are hard to manage at the end of their useful life due to the utilisation of binders or resins, which are known forms of carcinogens. Like other wood products, MDFs and particleboards can either be recovered for material recycling or energy recovery or sent to the landfill. This paper aims to identify the sustainable circular economy pathways for waste MDF and particleboard management, comparing three different scenarios: landfill, recycling, and energy recovery (incineration) via life cycle assessment methodologies (LCA). Life cycle assessment has been conducted using ReCiPe methodology of conducting life cycle assessment. The data analysis was conducted in MS Excel using @Risk v8.2 add-on function. The analysis was based on relative contribution of the impacts across the individual life cycle stages and the specific toxicity impacts were represented on a tornado chart to reflect the percentage spread of impacts across the life cycle phase. Finally, uncertainty analysis was conducted using Monte Carlo Simulation. The results showed that material recovery is preferred over energy recovery for most of the impact categories. However, energy recovery is preferred in the case of climate change and fossil fuel depletion. For both types of engineered wood products considered in this paper, end-of-life management of engineered woods has less impact than the production process. Toxicity impacts are the greatest for energy recovery compared with landfill and material recovery.
Global construction industry has a huge influence on world primary energy consumption, spending, and greenhouse gas (GHGs) emissions. To better understand these factors for mass timber construction, this work quantified the life cycle environmental and economic performances of a high-rise mass timber building in U.S. Pacific Northwest region through the use of life-cycle assessment (LCA) and life-cycle cost analysis (LCCA). Using the TRACI impact category method, the cradle-to-grave LCA results showed better environmental performances for the mass timber building relative to conventional concrete building, with 3153 kg CO2-eq per m² floor area compared to 3203 CO2-eq per m² floor area, respectively. Over 90% of GHGs emissions occur at the operational stage with a 60-year study period. The end-of-life recycling of mass timber could provide carbon offset of 364 kg CO2-eq per m² floor that lowers the GHG emissions of the mass timber building to a total 12% lower GHGs emissions than concrete building. The LCCA results showed that mass timber building had total life cycle cost of $3976 per m² floor area that was 9.6% higher than concrete building, driven mainly by upfront construction costs related to the mass timber material. Uncertainty analysis of mass timber product pricing provided a pathway for builders to make mass timber buildings cost competitive. The integration of LCA and LCCA on mass timber building study can contribute more information to the decision makers such as building developers and policymakers.
Structural health assessment of timber structures associates various procedures in order to evaluate the safety and serviceability of structures. Also, it helps to assure or extend the predicted service life of structures. Service life sustainability can be promoted by the incorporation of monitoring systems or by providing tools and methods that deliver accurate reports about the structural condition. Conservation and assessment of timber structures is based on a multidisciplinary approach. The conference topics cover the wide spectrum, from wood properties, through performance of joints and timber design, to modern monitoring and digital technologies. As the topics include both existing and historical timber structures, the need for reliable non destructive testing methods is part of the approach as well.
This paper discusses the ancient house building architecture which has been reflected in the text of Bṛhatsaṁhitā. Bṛhatsaṁhitā is verily associated with the Vedas or the knowledge of treasury. Vedas are four in numbers. In the tradition of knowledge, there are also four Upavedas- Dhanurveda, Stāpatyaveda, Gāndharvaveda and Āyurveda. Upavedas are actually known as the applied knowledge of science. These Upavedas are basically designed on technical work. There are so many literatures which have been composed by our ancient seers. Śrīvarāhamihira is the most efficient personality in the ancient science of knowledge. He has written the text of Bṛhatsaṁhitā. This is treated as the technical literature in the language of Sanskrit. There are one hundred and six chapters in this text. The knowledge of all the Upavedas are discussed clearly in this text. The Fifty three chapter of this text is named as Vāstuvidyā or the science of house building. The present study is an attempt to discuss the technique adopted in the science of ancient house building tradition according to Śrivarāhamihira.
Products derived from trees have been used by mankind for thousands of years, where timber has a long tradition as an ecological construction material. There is currently an increasing trend in multi-storey timber buildings, because of the projected growth in the demand for housing in urban areas between now and 2050, along with the urgent need for a more sustainable and productive construction industry. The construction of these buildings is now possible thanks to the new advances in architecture, engineering, and construction (AEC) and the new technological developments around timber construction. Its industrialization requirements imply a paradigm shift for the construction industry, which requires, among other aspects, the early and collaborative integration of stakeholders in its design and construction process. According to this, the objective of this review article is to determine the main advances and limitations related to the design and construction of multi-storey timber buildings, categorizing them in aspects such as sustainability, engineering and construction sciences, and collaborative design. The methodology of this article was based on the review of 266 articles published in Web of Science (WoS), as indexed scientific journals, between 2017 and mid-2022, performing a comparative and cooccurrence analysis of the contents. The results evidenced that 73% of the articles showed advances and limitations corresponding to the engineering and construction sciences category, 23% to sustainability, and the remaining 4% to collaborative design. The main advances in the development of multi-storey timber buildings are related to seismic analysis, connections design, fire performance, and fire design. While the main limitations are related to social sustainability, the results are not conclusive due to the low number of publications that support them.
Purpose-Whole building life cycle assessment (WBLCA) is a key methodology to reduce the environmental impacts in the building sector. Research studies usually face challenges in presenting comprehensive LCA results due to the complexity of assessments at the building level. There is a dearth of methods for the systematic evaluation and optimization of the WBLCA performance at the design stage. The study aims to develop a design optimization framework based on the proposed WBLCA method to evaluate and improve the environmental performance at the building level.
Design/methodology/approach-The WBLCA development method is proposed with detailed processes based on the EN 15978 standard. The environmental product declaration (EPD) methods were adopted to ensure the WBLCA is comprehensive and reliable. Building information modeling (BIM) was used to ensure the building materials and assembly contributions are accurate and provide dynamic material updates for the design optimization framework. Furthermore, the interactive BIM-LCA calculation processes were demonstrated for measuring the environmental impacts of design upgrades. The TOPSIS-based LCA results normalization was selected to conduct the comparisons of various building design upgrades.
Findings-The case study conducted for a residential building showed that the material embodied impacts and the operational energy use impacts are the two critical factors that contribute 60-90% of the total environmental impacts and resource uses. Concrete and wood are the main material types accounting for an average of 65% of the material embodied impacts. The air and water heating for the house are the main energy factors, as these account for over 80% of the operational energy use. Based on the original WBLCA results, two scenarios were established to improve building performance through the design optimization framework.
Originality/value-The LCA results show that the two upgraded building designs create an average of 5% reduction compared with the original building design and improving the thermal performance of the house with more insulation materials does not always reduce the WBLCA results. The proposed WBLCA method can be used to compare the building-level environmental performances with the similar building types. The proposed framework can be used to support building designers to effectively improve the WBLCA performance.
Wood is one of the basic natural renewable materials. Knowledge of its basic properties is the first prerequisite for its proper use in various industries and in human life. Wood is the most versatile and most used material (industry, construction, agriculture, everyday life). Due to its natural character, natural drawing, favorable physical properties, it is an increasingly desirable element of the environment. In the world, but also in our country, the trend of wooden buildings is becoming more and more widespread, not only in the understanding of cottages, wooden houses and family houses using wooden elements. We are talking about office buildings, non-residential premises, but also wooden high-rise buildings. Multi-storey wooden structures are a promising area of application of wood, which requires much less energy for their production compared to other "classic" materials. The aim of this paper is to present selected aspects of multi-storey wood-based buildings and their application at present.
Buildings have been shown to have impacts on the environment. Consequently, green building rating systems have become a tool to help reduce these impacts. The objectives of this study were to identify gaps in information and access to green building materials as viewed by Oregon design professionals. The scope was limited to the major structural materials: concrete, steel, and wood. This article focuses on the results unique to wood products. Information was collected through group interviews. Each group was composed of professionals representing different aspects of material selection and construction of different scales. The results showed that structural material selection is driven by building code, cost, and building performance requirements. The environmental performance of the material was not considered. However, once the material was selected, designers tried to maximize environmental performance. The results showed that green building rating systems do not influence structural material selection, and interviewees noted that there is room for improvement in this area. Respondents had a positive view of wood and a strong desire to use more wood, particularly Forest Stewardship Council certified wood. Wood was viewed as the most sustainable structural material available. However, there were some concerns about wood products, with formaldehyde emissions being the most significant.
Due to increasing demand for utility poles and the banning of native forests logging in Australia, it is necessary to find sustainable alternatives to roundwood utility poles. Currently, steel and concrete are the most common alternatives. Veneer-based composite (VBC) is a newly developed product made from hardwood plantation mid-thinning. To assess the viability of VBC, comparative life cycle assessment (LCA) and life cycle costing (LCC) analysis were conducted. Two end-of-life scenarios for VBC pole were assessed: incineration with energy recovery and landfilling. Five impact categories were considered: global warming (GWP); acidification (AP); eutrophication (EP); fossil depletion (FDP) and human toxicity (HTP). VBC pole with incineration showed the best environmental performance, particularly on GWP (63.22 kg-CO2-eq), AP (0.29 kg-SO2-eq), FDP (30.78 kg-Oil-eq) and HTP (2.27 kg-1,4-DB-eq), which are less than half of concrete and steel poles. However, VBC had higher EP than concrete and steel du
Hardwood plantations are slow to mature with low financial returns in the early stage. Veneer Based Composite (VBC) products developed from mid-thinning may improve the industry’s profitability and win new markets. Due to the increasing demand for utility poles and the banning of native forests logging in Australia, VBC poles may become viable alternative to native hardwood poles. Alkaline copper quaternary (ACQ) preservative treated VBC pole was assessed using life cycle assessment (LCA) methodology. The manufacturing processes considered were based on the current technologies in Queensland. VBC pole life cycle stages assessed include mid-thinning, manufacturing, service-life, and disposal. Three end-of-life scenarios were considered: landfilling, incineration for energy recovery and recycling as particleboard. The functional unit used in this assessment is 1-metre-length pole with 115-mm internal-diameter and 15-mm wall-thickness. Global Warming Potential (GWP100), Fossil Depletion Potential (FDP), Acidification Potential (AP), Eutrophication Potential (EP), and Ecological Toxicity Potential (ETP) were quantified. Results indicated that landfilling and incineration outperform the recycling option. Incineration scenario performed slightly better under the GWP100 (0.3659kg-CO -Eq), AP (2.12g-SO -Eq), FDP (0.360kg-Oil-Eq) and EP (3.81g-PO -Eq). Meanwhile, landfilling scenario had slightly less impact in ETP (12.32-CTUe). Despite generating valuable products, the burdens caused by secondary manufacturing and transportation overweighed credits earned from recycling. ACQ treatment, Phenol-formaldehyde (PF) resins production and transportation distances were identified as significant parameters affecting the final result. Sensitivity analysis indicated that EP was sensitive to change in ACQ consumption; ETP was affected by PF resin use while changing distances of transporting product affected GWP100, AP and FDP.
The objective of this project was to quantify and compare the environmental impacts associated with alternative designs for a typical North American mid-rise office building. Two scenarios were considered; a traditional cast-in-place, reinforced concrete frame and a laminated timber hybrid design, which utilized engineered wood products (cross-laminated timber (CLT) and glulam). The boundary of the quantitative analysis was cradle-to-construction site gate and encompassed the structural support system and the building enclosure. Floor plans, elevations, material quantities, and structural loads associated with a five-storey concrete-framed building design were obtained from issued-for-construction drawings. A functionally equivalent, laminated timber hybrid design was conceived, based on Canadian Building Code requirements. Design values for locally produced CLT panels were established from in-house material testing. Primary data collected from a pilot-scale manufacturing facility was used to develop the life cycle inventory for CLT, whereas secondary sources were referenced for other construction materials. The TRACI characterization methodology was employed to translate inventory flows into impact indicators. The results indicated that the laminated timber building design offered a lower environmental impact in 10 of 11 assessment categories. The cradle-to-gate process energy was found to be nearly identical in both design scenarios (3.5 GJ/m2), whereas the cumulative embodied energy (feedstock plus process) of construction materials was estimated to be 8.2 and 4.6 GJ/m2 for the timber and concrete designs, respectively; which indicated an increased availability of readily accessible potential energy stored within the building materials of the timber alternative.
Over the last two decades, the olive oil industry in Australia has been growing at an annual rate of 9%. Nevertheless, the highly polluting solid waste and wastewater generated by the industry poses significant challenges for the environmental sustainability of the industry. This paper analysed five alternatives for managing this waste stream using life cycle assessment methodology. The options included manufacturing briquettes as solid fuel for home heating; pellets for domestic or industrial water heating; pyrolysis and composting. The functional unit used in this study is the processing of 1 Mg of olive solid waste at the mill. Emissions were categorised into eight impact categories: ozone layer depletion potential (ODP), global warming potential (GWP100), eutrophication potential (EP), acidification potential (AP), human toxicity (HTP), fossil fuel depletion potential (FDP), ionising radiation potential (IRP), and photochemical oxidant formation potential (POFP). The study showed that although composting (current best practices – CBP) can achieve significant environmental benefits, using the olive waste to produce energy products may achieve better results, especially when displacing electricity from the main grid. The production of pellets for use in domestic hot water boilers (PHWH) is the option that is likely to deliver the highest environmental benefits. For example, GWP100 and ODP of the PHWH were estimated to be −1057 kg CO2-Eq, −1.5 × 10−5 kg CFC-11-Eq compared to −12.4 kg-CO2-Eq and 5.3 × 10−8 kg CFC-11-Eq achieved by the CBP, respectively. Future energy scenario and transportation distances were identified as significant parameters affecting the performance of the options. Sensitivity analysis showed that the expected change in the future Australian energy mix to cleaner energy sources is unlikely to have a significant effect on the performance of the alternatives. The results also showed little sensitivity to transportation distances of the energy product to the end user. This paper is the first to evaluate options for energy utilisation of olive solid waste using life cycle assessment and compare it to industry current best practices (composting). Although the paper focuses on the Australian olive oil industry, the results are also relevant to other countries and regions were olive solid waste is generated in relatively moderate quantities but distributed over large geographic area.
This study summarizes the environmental performance of prefinished engineered wood flooring using life-cycle inventory (LCI) analysis. Using primary mill data gathered from manufacturers in the eastern United States and applying the methods found in Consortium for Research on Renewable Industrial Materials (CORRIM) Research Guidelines and International Organization of Standardization (ISO) standard for conducting life-cycle assessments, the environmental impacts in making engineered wood flooring were estimated. This study is a follow-up to the CORRIM Report Module G—Life-Cycle Inventory of Solid Strip Hardwood Flooring in the Eastern United States. Life-cycle impact assessment was beyond the scope of this study.
Engineered wood flooring is designed to be more dimensionally stable than solid strip wood flooring because it is less susceptible to width shrinkage from increases in moisture. Engineered wood flooring as defined by the National Wood Flooring Association consists of several sheets of solid wood (veneer) bonded together with an adhesive under heat and/or pressure. Although plies having 2, 3, 5, 7, or 9 sheets are available, 3 and 5 are most common. Thicknesses can range from 3/8 to 9/16 in. (9.5 to 14.3 mm). Typical manufacturing includes the following eight unit processes: log yard, debarking and bucking, block conditioning, peeling and clipping, veneer drying, lay up, trimming, sanding, sawing and moulding (profiling), and prefinishing. Inputs and outputs to these unit processes were collected from a survey of manufacturers. The multi-unit process approach is the preferred evaluation method because it helps identify possible process improvements by showing the energy and environmental contribution of each unit process.
We determined the environmental impacts based on resource and energy consumption and releases to air, water, and land for making prefinished engineered wood flooring in the eastern United States. Of the five companies contacted in the eastern United States, four companies (comprising four veneer mills and five flooring plants) completed the mill survey. These facilities well represented the industry as a whole, and their manufacturing technology was average. Primary data were collected for the production period January to December 2007. Input data collected included raw materials such as hardwood logs with bark and water, resins, electricity, fossil fuels, prefinishing materials, transportation distances for materials used onsite, and the breakdown of logs into co-products sold (not flooring) such as wood chips and wood fuel burned onsite to produce thermal energy. Allocation of environmental inputs was done on a mass basis because the highest volume product had the highest economic value. This was true for all unit processes. Production unit bases of 1 m3 and 1,000 ft2, were selected to standardize the results to alternative products.
Based on surveyed data from the eastern United States, flooring production of 64,840 m2 (73,270 thousand ft2) was found. This was approximately 19% of the total 2007 engineered wood flooring production in the United States of 346,400 m2 (391,400 thousand ft2). No U.S. wood flooring production data were available by individual states. Surveyed mill production exceeded the minimum CORRIM production data requirement of 5%. In addition, this study met the minimum number of product manufacturers (four). Detailed inputs and outputs of unit processes were collected from these manufacturers and weight-averaged to allow modeling in SimaPro 7.1.8 to estimate emissions to air, water, and land. Results also include a carbon balance of the entire process.
After developing a mass balance from inputs and outputs, an ovendry density of 656 kg/m3 (40.9 lb/ft3) prefinished engineered wood flooring including wood, resins, and finish (coatings) was estimated. Assuming a specific gravity at 6% MC of 0.656, the density was 695 kg/m3 (43.4 lb/ft3). At 0% MC, the largest component of the flooring is wood (578 kg) and represents 88.2% of the final product mass, resins (65 kg) are 9.8%, and the remaining 2.0% finishing material (13 kg). Hardwood plywood and prefinished engineered wood flooring had wood recoveries of 43% and 35%, respectively. These numbers were determined by the output of wood in the form of plywood as a percentage by weight of the wood input to the manufacturing facilities in the log form (white wood only).
Energy consumption and type have significant effects on the environmental performance of all products. In this LCI study, unallocated thermal process energy and electricity consumed was 6,418 MJ/m3 (5.38 million Btu/thousand ft) and 1,113 kWh/m3 (985 kWh/thousand ft2), respectively. Wood fuel at 300 ovendry kg or 6,263 MJ/m3 (5.26 million Btu/thousand ft2) contributed 97.6% of process thermal energy required with the remainder from propane (2.2%) and natural gas (0.2%). Results showed a cumulative allocated value of manufacturing prefinished engineered wood flooring starting with logs at the forest landing to the final product leaving the flooring plant of 22,990 MJ/m3 (19.3 million Btu/thousand ft2) . Unfinished engineered wood flooring showed a cumulative allocated value of 13,600 MJ/m3 (11.4 million Btu/thousand ft2).
Tracking emissions is increasingly important in terms of applying proper emission controls. Two different scenarios were created to track emissions and involved system and onsite boundary conditions. First, the total (cumulative) system boundary covers both onsite and off-site emissions for all material and energy consumed. This includes the fuel resources used for the production of energy and electricity and is part of this LCI. Examples of off-site emissions are grid electricity production, transportation of logs to the mill, and fuels produced off-site but used onsite. The onsite system boundary covers emissions developed just at the prefinished engineered wood flooring facilities (i.e., onsite) from the seven unit processes. Environmental impact outputs from SimaPro were allocated to the production of 1 m3 of prefinished engineered wood flooring. A certain portion of the environmental impacts were assigned to the co-products such as wood chips and were not included in the LCI output for prefinished engineered wood flooring.
Data quality is considered excellent based on the data collected from the manufacturing facilities. We developed detailed surveys (questionnaires) that were reviewed by a CORRIM representative before distribution. In addition, a CORRIM representative reviewed the SimaPro model for this report. Onsite visits to a veneer mill and flooring plant allowed for provides greater insight into the manufacturing process, thus providing higher quality data. The multi-unit process method allows for unit process improvements to be evaluated more precisely than a system process approach.
Modeling data estimated biogenic and fossil CO2 emissions at 623 and 1,049 kg/m3, respectively, and VOCs at 1.04 kg/m3. A cubic meter of prefinished engineered wood flooring stores 1,096-kg CO2 equivalents/m3 as a final product.
The following main conclusions are based on the life-cycle inventory:
• The amount of carbon stored in prefinished engineered wood flooring exceeds the fossil carbon emissions by about 4%. Therefore, as long as prefinished engineered wood flooring and its carbon stay in products held in end uses, the carbon stored will exceed the fossil carbon emitted in manufacturing.
• A trade-off exists between prefinished and unfinished engineered wood flooring. The prefinishing unit process consumes a large amount of electricity from controlling emissions from staining and coating the wood flooring in addition to the prefinishing. As a result, the environmental impact is significantly higher for prefinished engineered wood flooring than for unfinished engineered wood flooring. However, finishing the wood floor after installation in a residential or commercial building (an uncontrolled environment) would result in greater harm to the environment. This harm results from uncontrolled emissions released from the staining and coating process that are now captured or destroyed onsite at the flooring plant.
• Burning fuel for energy generates CO2. Nearly all energy burned onsite for manufacturing prefinished engineered wood flooring comes from woody biomass. Burning biomass for energy does not contribute to increasing atmospheric CO2 provided forests are growing and absorbing the emitted CO2 on a sustainable basis.
• Increasing onsite wood fuel consumption would reduce fossil greenhouse gases but increase other gases, especially particulate emissions. Particulate matter can be captured prior to release to the atmosphere using commercially available technology but not without increased costs and additional inputs such as electricity.
The objective of this research is to quantitatively measure and compare the environmental load and construction cost of different structural frame types. Construction cost also accounts for the costs of CO2 emissions of input materials. The choice of structural frame type is a major consideration in construction, as this element represents about 33% of total building construction costs. In this research, four constructed buildings were analyzed, with these having either reinforced concrete (RC) or steel (S) structures. An input-output framework analysis was used to measure energy consumption and CO2 emissions of input materials for each structural frame type. In addition, the CO2 emissions cost was measured using the trading price of CO2 emissions on the International Commodity Exchange. This research revealed that both energy consumption and CO2 emissions were, on average, 26% lower with the RC structure than with the S structure, and the construction costs (including the CO2 emissions cost) of the RC structure were about 9.8% lower, compared to the S structure. This research provides insights through which the construction industry will be able to respond to the carbon market, which is expected to continue to grow in the future.
Wood is the most important renewable material. The management of wood appears to be a key action to optimise the use of resources and to reduce the environmental impact associated with mankind’s activities. Wood-based products must be analysed considering the two-fold nature of wood, commonly used as a renewable material or regenerative fuel. Relevant, up-to-date environmental data are needed to allow the analysis of wood-based products. The main focus of this study is to provide comprehensive data of one key wood board industry such as the Medium Density Fibreboard (MDF). Moreover, the influence of factors with strong geographical dependence, such as the electricity profile and final transport of the product, is analysed.
In this work, International Organization for Standardization standards (ISO 14040-43) and Ecoindicator 99 methodology have been considered to quantify the potential environmental impact associated to the system under study. Three factories, considered representative of the ‘state of art’, were selected to study the process in detail: two Spanish factories and a Chilean one, with a process production of around 150,000 m3 per year. The system boundaries included all the activities taking place into the factory as well as the activities linked to the production of the main chemicals used in the process, energy inputs and transport. All the data related to the inputs and outputs of the process were obtained by on-site measurements during a one-year period. A sensitive analysis was carried out taking into account the influence of the final transport of the product and the dependence on the electricity generation profile.
LCI methodology has been used for the quantification of the impacts of the MDF manufacture. The process chain can be subdivided in three main subsystems: wood preparation, board shaping and board finishing. The final transport of the product was studied as a different subsystem, considering scenarios from local to transoceanic distribution and three scenarios of electricity generation profile were assessed. The system was characterised with Ecoindicator 99 methodology (hierarchic version) in order to identify the ‘hot spots’. Damage to Human Health, Ecosystem Quality and Resources are mainly produced by the subsystem of Wood Preparation (91.1%, 94.8% and 94.1%, respectively). The contribution of the subsystem of Board Finishing is considerably lower, but also significant, standing for the 5.8% of the damage to HH and 5.5% of the damage to Resources.
With the final aim of creating a database of wood board manufacture, this work was focused in the identification and characterisation of one of the most important wood-based products: Medium Density Fibreboard. Special attention has been paid in the inventory analysis stage of the MDF industry. The results of the sensitive analysis showed a significant influence of both the final transport of the product and the electricity generation profile. Thus, the location of MDF process is of paramount importance,
as both aspects have considerable site-dependence.
Research continues to be conducted to identify the environmental burdens associated to the materials of extended use. In this sense, future work can be focused on the comparison of different materials for specific applications.
Background, aim and scopeForest operations use large amounts of energy, which must be considered when life cycle assessment (LCA) methodology is applied
to forest products. Forest management practices differ considerably between countries and may also differ within a country.
This paper aims to identify and compare the environmental burdens from forest operations in Sweden and Spain focused on pulpwood
production and supply to pulp mills.
Materials and methodsTo perform the analysis, the main forest plantations were investigated as well as the most important tree species used in
pulp mills in both countries: eucalyptus and, Norway spruce and Scots pine, were taken into account for the Spanish and Swedish
case studies, respectively. Energy requirements for pulpwood production and supply to Spanish and Swedish pulp mills are evaluated
in this paper. All forest operations from site preparation to extraction of felled wood to the delivery point at the roadside
are included within the system boundaries as well as wood transport from forest landing to the pulp mill gate. Seedling and
machinery production are excluded from the system boundaries due to lack of field data. The impact assessment phase was carried
out according to the Swedish Environmental Management Council and, in particular, the impact categories assessed in forest
and agricultural LCAs (global warming, acidification, eutrophication and photochemical oxidant formation) were analysed. SimaPro
7.10 software was used to perform the impact assessment stage.
ResultsDifferent types of wood are produced in both case studies: softwood in Sweden and hardwood in Spain, with higher production
of round wood and biomass per hectare in Sweden. Total energy use for pulpwood production and supply are in a similar order
of magnitude, up to 395MJ and 370MJ/m3 solid under bark in Spain and Sweden, respectively. Field operations, such as silviculture and logging, are more energy-intensive
in the Spanish case study. However, secondary hauling of pulpwood to pulp mill requires more energy in the Swedish case study.
These important differences are related to different forest management practices as well as to pulpwood supply to the pulp
mill. The eventual imports of pulpwood, application of pesticides, thinning step or final felling considerably affects energy
requirements, which are reflected on the environmental results.
DiscussionAlthough differences between both case studies were observed, several stages were investigated: wood delivery to the pulp
mill by road, harvesting and forwarding, contribute considerably to acidification, eutrophication and global warming potential
in both cases. The type of wood, the machines used in forest operations (mechanised or motor-manual), the use of fossil fuels
and the amount of wood produced influence the results. These differences must be kept in mind in comparative studies between
such different countries.
ConclusionsThe results obtained in this work allow one to forecast the importance of forest operations in LCA of forest products (in
this case, wood pulp) and the influence of energy use in the results. Special attention has been paid in the inventory analysis
stage for both case studies. It is possible to gain a better environmental performance in both case studies if alternative
practices are considered, mainly focused on site preparation and stand tending in the Spanish system and on pulpwood supply
in the Swedish one.
Recommendations and perspectivesThis study provides useful information that can assist forest-based industries in the aim of increasing their sustainability.
Future work will focus on the study of several transport alternatives of pulpwood supply including railway, road and ship.
In addition, pulpwood processing in Spanish and Swedish paper pulp mills considered to be representative of the “state of
art” will be carried out in order to get a complete picture of this kind of forest-based industry. In addition, the use of
biofuels (such as forest biomass) instead of fossil fuels and CO2 uptake of wood via photosynthesis will be carried out in order to have a complete perspective of forest ecosystems.
Life cycle assessments are used to compare the environmental effects of energy and global warming potential or carbon footprint of a three-storey timber building with alternative concrete, steel and low-energy timber buildings. The environmental effects are assessed with reference to greenhouse gas emissions, leading to global warming potential. Differences from previous studies are explored. A material carbon footprint calculation is proposed for possible inclusion in green building rating schemes, to compare the environmental impacts of building materials.
Wood composites are made from various wood or ligno-cellulosic non-wood materials (shape and origin) that are bonded together using either natural bonding or synthetic resin (e.g. thermoplastic or duroplastic polymers), or organic- (e.g. plastics)/inorganic-binder (e.g. cement). This product mix ranges from panel products (e.g., plywood, particleboard, strandboard, or fiberboard) to engineered timber substitutes (e.g., laminated veneer lumber or structural composite lumber). These composites are used for a number of structural and nonstructural applications in product lines ranging from interior to exterior applications (e.g. furniture and architectural trim in buildings). Wood composite materials can be engineered to meet a range of specific properties. When wood materials and processing variables are properly selected, the result can provide high performance and reliable service. Laminated composites consist of wood veneers bonded with a resin-binder and fabricated with either parallel- (e.g. Laminated Veneer Lumber with higher performance properties parallel to grain) or cross-banded veneers (e.g. plywood, homogenous and with higher dimensional stability). Particle-, strand-, or fiberboard composites are normally classified by density (high, medium, low) and element size. Each is made with a dry woody element, except for fiberboard, which can be made by either dry or wet processes. Hybrid composites based on wood wool, particles, and floor mixed with cement or gypsum are used in construction proving high weathering and fire resistance in construction. The mixture with plastics (PP or PE) and wood floor open a new generation of injected or molded Wood Plastic Composites (WPC), which are able to substitute plastics for some utilizations. In addition, sandwich panels with light core made from plastic foams or honeycomb papers are used in the furniture industry.
This paper uses an installation by the Canadian artists Cardiff and Miller to reflect on the nature of archival relationships and the possibilities of the archive as a fictional device. Road Trip is interpreted as a form of archive, creating relationships between different documentary layers that play out across time. It is suggested that the work's impact derives from the tensions between the evidentiary and the narrative characteristics of the different "documents." As an artwork, the constructed nature of Road Trip and its power to evoke an emotional response are obvious and intentional; nevertheless, these qualities are inherent in all archives. Art's power to move reminds us of the need to be aware of the latent and potential layers of meaning within archives and the multifarious relationships they both embody and construct.
This paper presents the Life-Cycle Assessment (LCA) of alternative building materials from forest resource regeneration or mineral extraction through product manufacturing, the assembly of products in constructing a residential home, occupancy and home repairs, and the eventual disposal or recycle. A unique feature of this study's LCA framework is that temporal distribution of events and associated environmental effects during the seed to demolition life cycle were considered by extending the scope to include forest growth through to demolition of the builidng. Our approach was to first conduct LCIs that quantified the energy, resource use, and emissions associated with a particular product, service, or activity. We followed this activity with the assessment of the house, and investigated the potential environmental consequences of energy and resource consumption and waste emissions. Finally we identified improvement opportunities for future research.
This review summarizes and organizes the literature on life cycle assessment (LCA), life cycle energy analysis (LCEA) and life cycle cost analysis (LCCA) studies carried out for environmental evaluation of buildings and building related industry and sector (including construction products, construction systems, buildings, and civil engineering constructions). The review shows that most LCA and LCEA are carried out in what is shown as "exemplary buildings", that is, buildings that have been designed and constructed as low energy buildings, but there are very few studies on "traditional buildings", that is, buildings such as those mostly found in our cities. Similarly, most studies are carried out in urban areas, while rural areas are not well represented in the literature. Finally, studies are not equally distributed around the world.
Australia’s agriculture industry, particularly in the north, is characterised by supply chains of long travel distances, often in excess of 2500 km and costing up to 35% of farm gate price. Such travel distances increase the vulnerability of the industry to climatic variability and extreme events. Infrastructure investments in roads, bridges, processors and storage, along with changes in policy, have the potential to substantially reduce costs and increase resilience of the agriculture industries. In this paper, we outline the model, TRAnsport Network Strategic Investment Tool (TRANSIT) which is based on ArcGIS, and utilizes the Origin to Destination Cost Matrix solver within the Network Analyst toolkit. TRANSIT estimates the transport costs for all movements between enterprises, accommodating road conditions, vehicle types, vehicle access restrictions and regulatory requirements. TRANSIT was applied to the northern Australia livestock industry, consisting of 12 million cattle across 10,000 enterprises and 89,000 unique trips between these enterprises. Its ability to estimate the transport benefits from road upgrades, new processing facilities and biosecurity changes are shown using three priority case studies identified by industry and government.
Cross-Laminated Timber is an engineered wood-based product, developed in Europe in the early 1990s. Cross-Laminated Timber is made of multiple layers of wood boards, which are oriented perpendicular to the adjacent layers. Cross Laminated Timber is a promising construction technology that represents an opportunity to use low-value timber from small diameter and insect-infested forest resources, for a high value-added application, which contributes to better use our forest resources. While Cross-Laminated Timber has been successful in Europe and is making its way into the Canadian and Australian markets, it has not yet been widely adopted in the United States. Research has proven that the rate of diffusion is dependent on potential adopters' perceptions of the product attributes, thus the study of perceptions play an important role in understanding and analyzing the adoption potential of a new product or technology. This document presents the results from research conducted to assess the market potential and barriers to the adoption of Cross-Laminated Timber in the United States, through the analysis of level of awareness, perceptions, and willingness to adopt Cross-Laminated Timber by the United States architecture community.
The aim of this article is to report a comprehensive review of life cycle assessment (LCA) and life cycle cost (LCC) implication on residential buildings. It discusses the contemporary issues, and its relationship and significance of system boundary, assumptions, and reports how it effects on economic and environmental impacts. The tools, frameworks and processes of LCA and LCC of buildings are also discussed. It critically illustrates the existing LCA and LCC studies on residential house designs to determine the causes for the widely varying results of numerous previous studies. It evaluates life cycle cost and life cycle environmental impacts of a case study building, and compares with very similar LCA and LCC studies. Finally, it reports the implications and perspectives of LCA and LCC studies on building designs.
Construction and building industry is in dire need for developing sustainability assessment frameworks that can evaluate and integrate related environmental and socioeconomic impacts. This paper discusses an analytic hierarchy process (AHP) based sustainability evaluation framework for mid-rise residential buildings based on a broad range of environmental and socioeconomic criteria. A cradle to grave life cycle assessment technique was applied to identify, classify, and assess triple bottom line (TBL) sustainability performance indicators of buildings. Then, the AHP was applied to aggregate the impacts into a unified sustainability index. The framework is demonstrated through a case study to investigate two six storey structural systems (i.e. concrete and wood) in Vancouver, Canada. The results of this paper show that the environmental performance of a building in Canada, even in regions with milder weather such as Vancouver, is highly dependent on service life energy, rather than structural materials.
With increasing focus on the environmental impacts of alternative land uses and materials, there is a growing need to produce accurate and verifiable life cycle inventories for forestry. A cradle-to-gate inventory was produced for wood from softwood plantations and hardwood native forests across Australia, covering all operations involved in forest establishment, management and harvesting and including transportation of logs and chips to processing facilities. The inventory was primarily based on data provided by forest growers, managers and contractors across seven case study regions. The SimaPro model was used to combine the different operations, and to account for upstream processes associated with the production of fuel and materials used. Forest products included high- and low-grade sawlogs, pulplogs, woodchips and other logs. Inputs were expressed in terms of m3 product and were allocated to products on an economic basis. Key inputs for wood from softwood plantations included land (0.06 ha m−3), water (0.12 ML m−3), diesel (172 MJ m−3) and fertiliser (0.3 kg N m−3, 0.2 kg P m−3, 0.06 kg K m−3). Key inputs for wood from native forests included land (0.28 ha m−3), water (0.38 ML m−3) and diesel (355 MJ m−3). The largest contributors to total energy use were log haulage (46% for softwood and 45% for hardwood) and harvesting and chipping (29% for softwood and 44% for hardwood). However, the total amount of energy used in the forestry production process (293 MJ m−3 for plantation softwood and 527 MJ m−3 for native hardwood) was very small relative to the net energy content of the logs harvested, representing just 4% of that in an average plantation softwood log and 6% of that in an average native hardwood log. Thus, forest products have low embodied energy and have strong potential for greenhouse gas mitigation when used for bioenergy.
Substitution between energy and CO2 intensive materials is a potentially important climate mitigation strategy. We compare buildings with concrete frames and wooden frames concerning their life-time carbon dioxide emissions as well as their total material, energy and carbon dioxide costs. By using consistent energy systems scenarios meeting stringent targets for atmospheric CO2 concentrations we investigate the impact of higher energy and carbon dioxide prices as well as of the availability of carbon capture and storage (CCS) technologies. We find that wooden frames cause lower carbon dioxide emissions given the prevailing energy system, but concrete frames obtain about the same emissions as the wood frame in a system where CCS is not used for wood incineration in the demolishing phase. The net present costs for the different buildings are also affected by the future energy supply system, even though the impact is small, especially compared to the total construction cost. We conclude that it is unclear whether wood framed buildings will be a cost-effective carbon mitigation option and that further analyses of costs should be performed before prescriptive materials policies are enforced in the buildings sector.
This paper reports on historical analysis of the steel industry in which crude steel production trends are quantified for the period from 1950 to 2006. On the basis of this analysis, the future production of steel for the world is estimated using regression analysis. The historical analysis shows that the world steel production increased from 187Mt to 1299Mt in that period. In addition, the paper also reports on historical (1950–2006) steel scrap consumption and was compared with crude steel and electric arc furnace (EAF) steel production. Since 1950, scrap consumption by steel industry worldwide has been growing at 12% per annum whereas the EAF share of steel production has been increasing at 66% per annum. Furthermore, since 1987 iron ore prices have increased at 24% per annum whereas scrap prices have grown by 13% per annum.From the analysis on environmental benefits of steel recycling, it was established that there are numerous advantages of scrap utilisation. The major environmental benefits of increased scrap usage comes from the very fact that production of one tonne of steel through the EAF route consumes only 9–12.5GJ/tcs, whereas the BOF steel consumes 28–31GJ/tcs and consequently enormous reduction in CO2 emissions. In addition, a discussion on various alloying elements in steel and their presence in residual concentrations in the scrap on steel properties is also presented. Finally, this paper presents a discussion on policy issues that could enhance the use of scrap in steel-making is also presented.
The building industry uses great quantities of raw materials that also involve high energy consumption. Choosing materials with high content in embodied energy entails an initial high level of energy consumption in the building production stage but also determines future energy consumption in order to fulfil heating, ventilation and air conditioning demands.This paper presents the results of an LCA study comparing the most commonly used building materials with some eco-materials using three different impact categories. The aim is to deepen the knowledge of energy and environmental specifications of building materials, analysing their possibilities for improvement and providing guidelines for materials selection in the eco-design of new buildings and rehabilitation of existing buildings.The study proves that the impact of construction products can be significantly reduced by promoting the use of the best techniques available and eco-innovation in production plants, substituting the use of finite natural resources for waste generated in other production processes, preferably available locally. This would stimulate competition between manufacturers to launch more eco-efficient products and encourage the use of the Environmental Product Declarations.This paper has been developed within the framework of the “LoRe-LCA Project” co-financed by the European Commission’s Intelligent Energy for Europe Program and the “PSE CICLOPE Project” co-financed by the Spanish Ministry of Science and Technology and the European Regional Development Fund.
A life-cycle Inventory (LCI) for Southeast oriented strandboard (OSB) manufacturing was conducted by surveying four OSB manufacturing plants in the Southeast. The survey responses were returned for 1999 production data and represented approximately 18% of OSB production in the survey region. All LCI data presented herein were based on a standard production unit of 0.88 m3 OSB panel product (1000 ft2, 3/8-inch basis). Southeastern OSB requires 771.6 kg (1701 lb, oven-dry basis) of roundwood raw material input. 545.7 kg (1203 lb) of this input ends in final OSB product, giving a total wood recovery of 71%. The remaining wood input ends as wood residue for fuel, wood residues sold as co-products, and wood waste sent to the landfill. On-site energy requirements for southeastern OSB are 5261 MJ (4.99 million BTU). Heat energy is the largest energy need, 89.6% of which is generated from combustion of wood residues. 182 kWh (655 MJ heat equivalent) of electricity is required for processing OSB. The highest use of fossil fuel (natural gas) is used to reduce VOC emissions in the emission control process at 465 MJ (4.4 million BTU). Considering the carbon cycle for on-site OSB production for a unit of product, OSB requires 396 kg (873 lb) of carbon from wood raw material. Other carbon input is utilized in the form of resins/wax (11.4 kg/25 lb) and fuels (12.3kg/27 lb). OSB holds 290 kg (640 lb or 69% of total carbon input) carbon. A small percentage of carbon (4%) is held in the form of co-products (e.g. mulch and wood residues). The remainder of carbon is released back to nature in the form of non-fossil CO2 (24%), fossil CO2 (3%), VOCs and other emissions (0.4%).
Buildings are major consumers of energy throughout their life cycle. Generation of energy primarily depends on conventional sources, which is the basic cause of environmental pollution. To improve environmental performance of building it is essential to involve all parameters which control its energy efficiency. Present paper identifies various parameters, viz. regulatory and voluntary policies, rating systems to assess energy efficiency, selection of energy efficient processes and materials through life cycle analysis and simulation and shifting to low embodied energy materials. A close control over each stage of development of a building is essential in the process of improvement in energy efficiency and reduction in carbon emission. In the following review construction of a building is divided in planning phase, designing phase, execution phase and operating phase. Policy makers, architects, structural designers, energy managers, construction managers and consultants must be involved in the development of a building for improving its overall environmental performance.
Aims Australia is among one of the world’s wealthiest nations; yet, its relatively small human population (22.5 million) has been responsible for extensive deforestation and forest degradation since European settlement in the late 18th century. Despite most (∼75%) of Australia’s 7.6 million-km2 area being covered in inhospitable deserts or arid lands generally unsuitable to forest growth, the coastal periphery has witnessed a rapid decline in forest cover and quality, especially over the last 60 years. Here I document the rates of forest loss and degradation in Australia based on a thorough review of existing literature and unpublished data.
Important Findings Overall, Australia has lost nearly 40% of its forests, but much of the remaining native vegetation is highly fragmented. As European colonists expanded in the late 18th and the early 19th centuries, deforestation occurred mainly on the most fertile soils nearest to the coast. In the 1950s, southwestern Western Australia was largely cleared for wheat production, subsequently leading to its designation as a Global Biodiversity Hotspot given its high number of endemic plant species and rapid clearing rates. Since the 1970s, the greatest rates of forest clearance have been in southeastern Queensland and northern New South Wales, although Victoria is the most cleared state. Today, degradation is occurring in the largely forested tropical north due to rapidly expanding invasive weed species and altered fire regimes. Without clear policies to regenerate degraded forests and protect existing tracts at a massive scale, Australia stands to lose a large proportion of its remaining endemic biodiversity. The most important implications of the degree to which Australian forests have disappeared or been degraded are that management must emphasize the maintenance of existing primary forest patches, as well as focus on the regeneration of matrix areas between fragments to increase native habitat area, connectivity and ecosystem functions.
A Correction has been published for this article in Progress in Structural Engineering and Materials 3(4) 2001, 361.
Engineered wood products are structural composites that have been gaining successes in the construction industry. The mechanical and physical properties of these products depend on the interacting relationships between the quality of the resource, the manufacturing process, and the applications. In general their mechanical properties are more uniform compared with solid sawn material; hence, higher allowable properties are available in engineering design. This paper reviews the manufacturing processes, structural properties, physical attributes, and common applications of some of the major engineered wood products including: glued‐laminated timber, parallel strand lumber, laminated strand lumber, laminated veneer lumber, and thick oriented strand board/rimboard.
In this study a method is suggested to compare the net carbon dioxide (CO2) emission from the construction of concrete- and wood-framed buildings. The method is then applied to two buildings in Sweden
and Finland constructed with wood frames, compared with functionally equivalent buildings constructed with concrete frames.
Carbon accounting includes: emissions due to fossil fuel use in the production of building materials; the replacement of fossil
fuels by biomass residues from logging, wood processing, construction and demolition; carbon stock changes in forests and
buildings; and cement process reactions. The results show that wood-framed construction requires less energy, and emits less
CO2 to the atmosphere, than concrete-framed construction. The lifecycle emission difference between the wood- and concrete-framed
buildings ranges from 30 to 130 kg C per m2 of floor area. Hence, a net reduction of CO2 emission can be obtained by increasing the proportion of wood-based building materials, relative to concrete materials. The
benefits would be greatest if the biomass residues resulting from the production of the wood building materials were fully
used in energy supply systems. The carbon mitigation efficiency, expressed in terms of biomass used per unit of reduced carbon
emission, is considerably better if the wood is used to replace concrete building material than if the wood is used directly
as biofuel.
Goal, Scope and Background The goal of the study is a life cycle assessment according to ISO 14040 –14043 for wood floor coverings (solid parquet, multilayer
parquet, solid floor board and wood blocks). The representative study covers approximately 70% of all wood flooring production
in Germany. The comparison of the floor coverings among each other was not the aim. Instead the study provides basic data
for all wood floor coverings for a possible comparison with other floor coverings later on. The main focus was a hot spot
analysis to help the involved industry partners to improve their environmental performance, and to use the results for marketing
purposes.
-Inventory Analysis. The study covers the whole life cycle from forest management, sawmilling, manufacturing, laying and surface
finishing through to refurbishment and end-of-life. The end-of-life scenario is the thermal utilisation of the floor coverings.
The energy gained in the end-of-life scenario is accounted for by system expansion (avoided burden approach).
-Impact Assessment. In the Impact Assessment the following categories were considered: global warming (GWP), acidification
(AP), eutrophication (EP), ozone depletion (ODP) and photo-oxidant formation (POCP) following the CML baseline 2000 method.
Furthermore the use of primary energy is presented.
The low emissions of greenhouse gases during the life cycle can lead to a negative contribution to the global warming potential
if more emissions are avoided through the substitution process than are emitted during the life cycle of the product. Mainly
energy consumption and the use of solvents influence the environmental impacts of the systems under analysis. The most relevant
unit processes for the issue of energy consumption are 'production' and for photo-oxidant formation 'laying', 'surface finishing'
and 'refurbishment'. These are therefore the unit processes with the greatest potential for improvement.
-Normalisation and Sensitivity Analysis. The normalisation results show that the photo-oxidant formation potential is most
significant in comparison to the other impact categories. Improvement options and the choice of the functional unit have been
further explored in a sensitivity analysis.
Discussionand Conclusions. The most important opportunities for improvements are located in the unit processes laying, surface finishing
and refurbishment. The POCP result can be reduced significantly depending on the choice of glue and varnish at each of these
stages. The results of the sensitivity analysis showed a potential for improvement in this category. No data for the production
of an oil and wax finish was available. This option would be interesting to consider at in a further study. The time aspect
of storing CO2 for a period of time is not considered in this paper, but will be addressed in a forthcoming paper (Nebel and
Cowell 2003).
This paper develops a model of expectations which generates paths that are consistent with observations that an acceleration of the monetary growth rate initially raises and eventually lowers real holdings of cash balances. It introduces a two-part expectations hypothesis where individuals are assumed to form expectations about the entire path of the price level and about the short-term inflation rate. Interaction between regressive and extrapolative elements induces a transitory rise in money holdings during the initial phase of inflation as expectations are that the process will reverse itself. Subsequently, as expectations catch up, the decline in desired holdings induces an overshooting of the inflation rate.
In this study we examine the use of wood products as a means to mitigate climate change. We describe the life cycle of wood products including forest growth, wood harvest and processing, and product use and disposal, focusing on the multiple roles of wood as both material and fuel. We present a comparative case study of a building constructed with either a wood or a reinforced concrete frame. We find that the production of wood building material uses less energy and emits less carbon than the production of reinforced concrete material. We compare the relative cost of the two building methods without environmental taxation, under the current Swedish industrial energy taxation regime, and in scenarios that incorporate estimates of the full social cost of carbon emission. We find that the inclusion of climate-related external costs improves the economic standing of wood construction vis-à-vis concrete construction. We conclude that policy instruments that internalise the external costs of carbon emission should encourage a structural change toward the increased use of sustainably produced wood products.
We study the opportunities to increase the use of wood in the Dutch residential construction sector and assess the effects on material related CO2 emission. Four house types are modeled with increasing quantities of wood used in constructions. CO2 emission reductions of almost 50% are technically possible. We assess the innovation characteristics of these wood applications to create insights in the complexity of the necessary change process. Then we relate the innovation characteristics of the wood options to the context in which implementation of the technologies take place. The options vary strongly in the required technical and network changes and so do the opportunities to implement them. Based on this we expect that a 12% CO2 emission reduction related to material use for residential buildings is possible in the short term by an increased share of wood use. We also study the possibilities for increased wood recycling practices. A large technical potential exists. To achieve this potential a significant policy effort is needed since significant changes in both technical and network dimensions are necessary. To stimulate innovation in the use of wood in residential construction, important focus points of policy making should be the culture in the Dutch construction sector, the way new building projects are commissioned, research areas within the building sector, and stabilization of building networks.
In this paper, primary energy use and carbon dioxide (CO2) and methane (CH4) emissions from the construction of a multi-storey building, with either a wood or a concrete frame, were calculated from life-cycle and forest land-use perspectives. The primary energy input (mainly fossil fuels) in the production of building materials was found to be about 60–80% higher when concrete frames were considered instead of wood frames. The net greenhouse gas (GHG) balance for wood materials will depend strongly on how the wood is handled after demolition of the building. The nrt GHG balance will be slightly positive if all the demolition wood is used to replace fossil fuels, slightly negative if part of the demolition wood is re-used, and clearly positive if all wood is deposited in landfills, due to the production of CH4. However, if the biogas produced is collected and used to replace fossil fuels, the net GHG emissions will be insignificant. If concrete frames are used, the net GHG emissions will be about those when demolition wood from the wood-framed building is deposited in landfills and no biogas is collected. We have considered that the CO2 released from the chemical processes in the production of cement will be re-bound to the concrete by the carbonisation process. Otherwise, the net GHG emission would be more than twice as high when concrete frames are used. If forest biomass is used instead of fossil fuels, the net area of forest land required to supply both raw material and energy for the production of building materials, will be about twice as high when wood frames are used instead of concrete frames. However, the GHG mitigation efficiency, expressed as CO2 equivalents per unit area of forest land, will be 2–3 times higher when wood frames are used if excess wood waste and logging residues are used to replace fossil fuels. The excess forest in the concrete frame alternative is used to replace fossil fuels, but if this forest is used for carbon storage, the mitigation efficiency will be higher for the first forest rotation period (100 yr), but lower for the following rotation periods. Some of the data used in the analyses are uncertain, but an understanding of the complexity in comparing different alternatives for utilising forest for GHG mitigation, and of the fact that the time perspective applied affects the results markedly, is more important for the results than the precise figures in the input data.
This study investigates the global impact of wood as a building material by considering emissions of carbon dioxide to the atmosphere. Wood is compared with other materials in terms of stored carbon and emissions of carbon dioxide from fossil fuel energy used in manufacturing. An analysis of typical forms of building construction shows that wood buildings require much lower process energy and result in lower carbon emissions than buildings of other materials such as brick, aluminium, steel and concrete. If a shift is made towards greater use of wood in buildings, the low fossil fuel requirement for manufacturing wood compared with other materials is much more significant in the long term than the carbon stored in the wood building products.As a corollary, a shift from wood to non-wood materials would result in an increase in energy requirements and carbon emissions.The results presented in this paper show that a 17% increase in wood usage in the New Zealand building industry could result in a 20% reduction in carbon emissions from the manufacture of all building materials, being a reduction of about 1.5% of New Zealand’s total emissions. The reduction in emissions is mainly a result of using wood in place of brick and aluminium, and to a lesser extent steel and concrete, all of which require much more process energy than wood. There would be a corresponding decrease of about 1.5% in total national fossil fuel consumption. These figures have implications for the global forestry and building industries. Any increases in wood use must be accompanied by corresponding increases in areas of forest being managed for long term sustained yield production.
Cure time is often the bottleneck of composite manufacturing processes, therefore it is important to understand the cure of today's thermosetting adhesives. This research attempts to characterize the cure rate of two commercial phenol-formaldehyde adhesives. Two methods are used, parallel-plate rheometry and dielectric spectroscopy. Viscosity data from a parallel-plate rheometer may be used to track the advance of polymerization as a function of temperature. This data can then be used to optimize press conditions and reduce production times and costs. The research will further examine resin cure through dielectric analysis; such a technique could monitor resin cure directly and in real-time press situations. Hot-pressing processes could conceivably no longer require a set press schedule; instead they would be individually set based on dielectric data for every press batch. Such a system may lead to a more efficient and uniform product because press times could be based on individual press cycles instead of entire product lines. A more likely scenario, however, is the use of in situ adhesive cure monitoring for troubleshooting or press schedule development. This research characterized the cure of two phenol-formaldehyde resins using parallel-plate rheometry, fringe-field dielectric analysis, and parallel-plate dielectric analysis. The general shape of the storage modulus vs. time curve and the gel and vitrification points in a temperature ramp were found. Both dielectric analysis techniques were able to characterize trends in the resin cure and detect points such as vitrification. The two techniques were also found to be comparable when the cure profiles of similar conditions were examined. System requirements: PC, World Wide Web browser, and PDF reader. Available electronically via the Internet. Title from electronic submission form. Thesis (M.S.)--Virginia Polytechnic Institute and State University, 2005. Vita. Abstract. Includes bibliographical references.
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