Low carbon construction systems using prefabricated engineered solid wood panels for urban infill to significantly reduce greenhouse gas emissions

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  • Sustainable Cities and Society 6 (2013) 5767

    Contents lists available at SciVerse ScienceDirect

    Sustainable Cities and Society

    journa l h ome page: www.elsev ier .c

    Low ca ricpanels ree

    Steffen Lsd+b Research

    a r t i c l

    Keywords:Multi-storey inLow carbon coSolid wood pa

    onstroad-bt oppweven indies ofwn asuctioany:

    pacityinto engineered timber panels which aims to transform the Australian construction and developmentindustry, involving a range of key partners. This project aims to introduce CLT panels as a way to buildwith a lightweight prefabricated low-carbon construction system that is advantageous for urban inlland residential buildings in the range of 410 stories height. The challenges, research questions andadvantages of this new engineered timber system are explained, and a research methodology for further

    1. Introdu

    The tradAustralia anenergy, matand the gretion and inesystem hasurban wastthe consumtial and eveas the constmethods reand are bamaterials (L

    Rethinkibehaviour ito deliver simental degthe constru

    Tel.: +61 8E-mail add

    2210-6707/$ http://dx.doi.oresearch is presented. 2012 Published by Elsevier B.V.

    ction

    itional model of greeneld housing development ind the U.S. is unsustainable because of the quantity oferials and water used, land consumed, waste generated,enhouse gas emissions that result from high consump-fciencies. The ow of raw materials through the urban

    not received adequate attention because the topic ofe is unglamorous albeit extremely important. Reducingption of materials in the construction sector is essen-n more important than recycling of building materials,ruction of buildings and neighbourhoods using currentquire vast amounts of energy generated by fossil fuelssed on linear one-way throughput of non-renewableehmann, 2011).ng the way we deal with material ows and changingn regard to waste streams and waste avoidance, is likelygnicant improvements and curb the threat of environ-radation and global warming. But how does this affectction sector? The research the Sustainable Design and

    8302 0654.ress: Steffen.Lehmann@unisa.edu.au

    Behaviour (sd+b) Research Centre is involved with explores a widerange of topics around consumption and waste of materials, mate-rial ows, and solutions for better management of resources forurban development. The university understands itself as a plat-form for the exchange of knowledge and ideas in these areas,bringing together representatives from academia with industry,government and local communities.

    We have borrowed from the planet for a long time, exceedingits carrying capacity, and if our society and economy are not trans-formed we risk descent into unhealthy urban conditions, loss ofprecious biodiversity, and depletion of virgin materials. Our currentmodel of economic and urban growth is driving this unhealthy sys-tem, and, as a consequence, we have passed the limits of our planetscapacity to support us. Over the last 20 years, the amount of wasteAustralians produce has more than doubled, and it is likely that thisamount will double again between 2011 and 2020: the amount ofwaste generated in Australia grows currently by around 67 percent per year (National Waste Report, 2010).

    The notion of waste is based on the assumption that energyand materials, having once served the construction sectors imme-diate purposes, simply cease to exist in any functional sense,and that the only possibility is dumping these mis-allocatedresources in landlls. Or, to borrow a word from Mumford (1961),current construction methods are paleotechnic, representing

    see front matter 2012 Published by Elsevier B.V.rg/10.1016/j.scs.2012.08.004rbon construction systems using prefabfor urban inll to signicantly reduce g

    ehmann

    Centre, University of South Australia, GPO Box 2471, Adelaide SA5001, Australia

    e i n f o

    ll housingnstructionnel systems

    a b s t r a c t

    Low-carbon prefabricated modular cpanel construction systems, such as lsembly principles will offer signicanavoidance, among other benets. Hosystems to the Australian constructio

    This paper explores the opportunitcross-laminated timber (CLT, also knoinll housing of the Australian constrin Europe, mainly in Austria and Germdirections to increase loadbearing caom/ locate /scs

    ated engineered solid woodnhouse gas emissions

    uction systems, using prefabricated engineered solid woodearing cross-laminated timber panels, and design for disas-ortunities for greenhouse gas emission reduction and waster, introducing such innovative and sustainable constructionustries and housing markets has its challenges.fered by an innovative low carbon construction system using

    cross-lam) panels to improve the design and delivery of urbann market. CLT construction has been developed around 1996

    thick layers of timber boards are glued crosswise in different. This article describes a multi-disciplinary research project

  • 58 S. Lehmann / Sustainable Cities and Society 6 (2013) 5767

    unsustainable behaviour based on primitive, exploitative tech-nologies rather than regenerative ones. However, the re-use ofbuilding components and construction materials would not onlyreduce the amount of waste created, but also allow for recyclingand retrotments have2011).

    Timber, prime impoversatility, plasterboarenergy in therably to CO

    Prefabritems can se(CLT, also cengineeredcan be usedor higher. Mentirely in their socialica is at thpossible if t

    Wood islow embodfabricated esustainablearound thecapacity totime, solid wbuildings inronmental turned arou

    One cubing timber ton the envimary energthat has noenergy conas input to have a lowsteel buildishouldnt o

    Wegnerproducts anenergy oveand disposatheir produtheir life cymaterial is mate effect4).

    This papcross-laminAustralian crange of ketimber panlow-carboninll and reand advant

    1.1. Why trimportant

    We are is not eaten

    return nutrients to the soil, nor in a biogas plant to generate energy(George, 2009). Our resources are limited and endless consumptionand growth is impossible. If we cut down more trees than we grow,at some point we run out of trees. Passing the limits has conse-

    s, ass, an

    (Buckics sate

    tralision osourclic trakingre livntly ptio

    futugs aher rte leesignditiogas (endeto dedeveea nnstruces al) mproaand ies o

    ition inte0s h

    const an

    to chefforesili

    lifesgeviex ecustr

    -use we w

    not g, 20

    rban

    idenons w

    wilenets. Ds (thives he ciransi. The

    on wnd ch peting of entire neighbourhoods or districts, once require- changed (Lattke & Lehmann, 2007; Zaman & Lehmann,

    arguably the original building material, retains itsrtance within the construction industry because of itsdiversity and aesthetic properties. Brick, steel, glass,d, concrete and particularly aluminium, all use moreeir production than timber, thus contributing consid-2 emissions (Lyons, 2010).

    cated engineered solid wood panel construction sys-quester and store CO2. Modular cross-laminated timberalled cross-lam) panels form the basis of low-carbon,

    construction systems using solid wood panels that to build residential inll developments of 10 storeysulti-apartment buildings of 410 storeys constructed

    timber, such as recently in Europe, are innovative, but and cultural acceptance in Australia and North Amer-is stage still uncertain. Commercial utilisation is onlyhere is a demand and user acceptance.

    an important contemporary building resource due to itsied energy and unique attributes. The potential of pre-ngineered solid wood panel systems, such as CLT, as a

    building material and system is only just being realised globe. Since timber is the only material that has the

    store carbon in large quantities over a long period ofood panel construction offers the opportunity to turn

    to carbon sinks. Thus the historically negative envi-impact of urban development and construction can bend with CLT construction on browneld sites.ic metre of wood stores around one tonne of CO2, mak-he only construction material that can impact positivelyronment. Generally, timber buildings require less pri-y consumption (primary energy is the energy formt been subjected to any transformation process; it istained in raw fuels and other forms of energy receiveda system; it can be non-renewable or renewable) ander Global Warming Potential (GWP) than concrete orngs (the difference can be 25 per cent or more). Ideally,ur buildings be like trees and our cities like forests?

    and his colleagues noted that the energy budgets ofd buildings made of wood show that they may use lessr their total life cycle (manufacture, use, maintenancel) than can be recovered from the waste products ofction and from their recycling potential at the end ofcle: they are energy-positive. No other constructionso comprehensively energy-efcient and therefore cli-ive as wood (Wegener, Pahler, & Tratzmiller, 2010, p.

    er describes a multi-disciplinary research project intoated timber (CLT) panels which aims to transform theonstruction and development industry and involves ay partners. This project will introduce cross-laminatedels as a way to build with a lightweight prefabricated

    construction system that is advantageous for urbansidential buildings. The challenge, research questionsages of this system are explained below.

    ansforming the current system of over-consumption is

    a wasteful nation. For instance, 40 per cent of all food, it is th