This study compares the life cycle environmental impacts of two multilevel residential buildings built in Melbourne, Australia. The study was commissioned by Australand and funded by Forest and Wood Products Australia (FWPA).
The first building considered, the ‘Study Building’, incorporated an innovative light weight building approach utilising a stick-built timber frame and a ‘cassette floor’ building system. The second building, the ‘Reference Building’ utilised a more typical building approach, incorporating precast concrete panels and suspended concrete slab floors (Table 1).
The primary goal of the study was to compare the potential environmental impacts of the above buildings across their respective life cycles.
The study employed the LCA methodology described by the ISO14044 standard to undertake the comparison of the buildings. The analysis addressed a building life cycle scope which was prescribed by GBCA (GBCA 2014), which in turn based the boundary definition on the EN15978 standard, as shown in Figure 1. Although EN15978 was used to define the scope of the LCA, the study is not intended to be fully compliant with the standard.
The purpose of this research is to evaluate the environmental performance of various timber constructions that have been realised within intensively utilised area in recent years. The appraisal is carried out by means of life cycle assessment (LCA) and covers different timber constructions, mainly the multi-storey building. The ultimate goal is to compare their environmental performance to the outcomes of other constructions like reinforced concrete (RC) and steel construction (SC).
The environmental burdens caused by constructions are evaluated based on the framework of LCA. First, the material inventory of selected building projects is established. The scope is emphasised on the primary structural elements such as columns, beams, deck, load-bearing wall and roof. Secondary components, facility and decoration are eliminated out of the research boundary. Based on the material inventory, the impact assessment is carried out to preliminarily calculate the embodied outcome of the timber constructions. The environmental implications of structural elements during early life cycle stages are evaluated. Then, the effect of both disposal and material recycling is integrated in the LCA, including reuse or recovery of the structural wooden components. The LCA takes into account different disposal scenarios associated with construction and demolition waste (C&DW). By doing so, the LCA is the so-called ‘from cradle to gate’ and ‘gate to cradle’, without consideration upon the using phase. Among numerous environmental indictors, this research quantifies and discusses the energy consumption and global warming potential (GWP) of the timber buildings only.
The five-storey timber building located in urban context is a pioneer project in Taiwan. This building applies crosslaminated-timber (CLT) as the primary structural elements and takes over tremendous loading circumstances. It demonstrates not only the engineering feasibility of CLT for architectural design but also the utilising compatibility of wooden house in urban context.
The environmental evaluation proofs the ecological efficiency of timber buildings. In addition, this study compares the environmental performance of timber constructions and other materials. Alternative building models made of RC and steel are developed and intended for further LCA. The LCA results demonstrate that timber constructions cause significantly less impacts than RC and SC do. Timber constructions exhibit carbon sequestration effect, which is unique among three materials. Meanwhile, timber constructions consume only about 20% energy of the RC and SC. While possessing similar form and functionality, timber constructions exhibit better eco-efficiency compared to other generally used materials. When the material recycling is taken into account, the life-cycle eco-efficiency of timber structures is further significant. Wooden constructions can be energy-neutral or even energy-productive, depending on the recycling strategies.
This paper reports on a study examining the potential of reducing greenhouse gas (GHG) emissions from the building sector by substituting multi-storey steel and concrete building structures with timber structures. Life cycle assessment (LCA) is applied to compare the climate change impact (CC) of a reinforced concrete (RC) benchmark structure to the CC of an alternative timber structure for four buildings ranging from 3 to 21 storeys. The timber structures are dimensioned to meet the same load criteria as the benchmark structures. The LCA comprises three calculation approaches differing in analysis perspective, allocation methods, and modelling of biogenic CO2 and carbonation of concrete. Irrespective of the assumptions made, the timber structures cause lower CC than the RC structures. By applying attributional LCA, the timber structures are found to cause a CC that is 34-84% lower than the RC structures. The large span is due to different building heights and methodological assumptions. The CC saving per m2 floor area obtained by substituting a RC structure with a timber structure decrease slightly with building height up to 12 storeys, but increase from 12 to 21 storeys. From a consequential LCA perspective, constructing timber structures can result in avoided GHG emissions, indicated by a negative CC. Compared to the RC structures, this equal savings greater than 100%.
Lend Lease is constructing a new residential building using cross laminated timber (CLT). This
material is a relatively new building material in Australia, which has found increased use in multi-story residential and commercial buildings, particularly in Europe. The Centre for Design (CfD), School of Architecture and Design, RMIT University was commissioned by Lend Lease through Forest and Wood Products Australia (FWPA), to investigate the environmental performance associated with the production of the materials, along with HVAC and lighting systems, and associated operation and end-of-life of this novel building, using a life cycle approach.
Life Cycle Assessment (LCA) has been used as the core method for determining the potential
environmental impacts of the products considered. LCA has been applied in accordance with ISO
14040:2006. Data on the building materials quantities and construction details were supplied by Lend Lease, background life cycle inventory data was gathered from Australian (AUPLCI) and European (Ecoinvent) databases. Data on cross laminated timber was provided by the manufacturer in an Environmental Product Declaration (EPD). Annual operational energy use for the Forté and the reference buildings were calculated using the dynamic building energy simulation software tool ApacheSim. The simulation results for residential spaces were validated against results from an Accurate assessment.
This document provides supporting information for LEED accreditation of the Wood Innovation and Design Centre (WIDC) in Prince George British Columbia. In particular, this document supports materials and resources pilot credit 63 - whole building life cycle assessment - in LEED BC+C: Core and shell v2009. The baseline building design for comparison is a reinforced concrete structure with light gauge steel envelope walls. The WIDC building is a mass timber building with cross-laminated timber used for the floors and stairwell/elevator core and structural insulated panels for the envelope walls. This work shows multi-storey office buildings in BC with mass timber structural systems and laminated veneer lumber curtain wall structures can have environmental performance improvements for non-renewable energy consumption, global warming potential, particulate matter formation and smog potential when compared to reinforced concrete buildings with aluminum-framed curtain walls. Reducing global warming potential requires future emphasis on reduced operational energy consumption.