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 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 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.
EBD was first developed by the Athena Sustainable Materials Institute. An EBD is a summary report of the comprehensive environmental footprint data for a building and declares life-cycle impacts according to a standardized format. It is a statement of performance and is publicly disclosed, similar to a nutrition label on a food package. The intent of the document is to present results as transparently and concisely as possible.
Athena’s EBDs are compliant with the European standard EN 15978, a whole-building LCA standard that is intended to support decision-making and documentation around the assessment of environmental performance of buildings. The Design Building would be the fourth building to be assessed as part of Athena’s EBD initiative and the first located in the United States.
Relying on China’s national standard “Standard for Building Carbon Emission Calculation” and related reports published by the Athena Institute, this report calculates the life cycle carbon emissions of wood buildings in China. The study collects basic information of all the projects, such as quantity of building materials, building envelope, energy system and so on. Calculations are conducted for 7 projects from the aspects of product stage, transportation stage, construction stage, operational energy and demolition stage
Timber building has gained more and more attention worldwide due to it being a generic renewable material and having low environmental impact. It is widely accepted that the use of timber may be able to reduce the embodied energy of a building. However, the development of timber buildings in China is not as rapid as in some other countries. This may be because of the limitations of building regulations and technological development. Several new policies have been or are being implemented in China in order to encourage the use of timber in building construction and this could lead to a revolutionary change in the building industry in China. This paper is the first one to examine the feasibility of using Cross Laminated Timber (CLT) as an alternative solution to concrete by means of a cradle-to-grave life-cycle assessment in China. A seven-storey reference concrete building in Xi’an was selected as a case study in comparison with a redesigned CLT building. Two cities in China, in cold and severe cold regions (Xi’an and Harbin), were selected for this research. The assessment includes three different stages of the life span of a building: materialisation, operation, and end-of-life. The inventory data used in the materialisation stage was mostly local, in order to ensure that the assessment appropriately reflects the situation in China. Energy consumption in the operation stage was obtained from simulation by commercialised software IESTM, and different scenarios for recycling of timber material in the end-of-life are discussed in this paper. The results from this paper show that using CLT to replace conventional carbon intensive material would reduce energy consumption by more than 30% and reduce CO2 emission by more than 40% in both cities. This paper supports, and has shown the potential of, CLT being used in cold regions with proper detailing to minimise environmental impact.
The 58th International Convention of Society of Wood Science and Technology
June 7-12, 2015, Grand Teton National Park, Jackson, Wyoming, USA
Documenting the environmental performance of building products is becoming increasingly common. Developing environmental product declarations (EPDs) based on life-cycle assessment (LCA) data is one way to provide scientific documentation. Many U.S. structural wood products have LCA-based “eco-labels” using the ISO standard. However, the standard requires underlying life-cycle inventory (LCI) data to be of recent age. This study updates the gate-to-gate manufacturing LCI data for laminated veneer lumber (LVL) for Pacific Northwestern (PNW) and for southeastern (SE) United States. Modeling the primary industry data per 1.0 m3 of LVL through LCI analysis provides the inputs and outputs from veneer logs to LVL starting at the forest landing. For PNW and SE, cumulative mass-allocated energy consumption associated with manufacturing 1.0 m3 of LVL was found to be 5.64 and 6.87 GJ/m3, respectively, with about 25% of the primary energy derived from wood residues. Emission data produced through modeling found that estimated biomass and fossil CO2 emissions in kg/m3 were 127 and 139 for the PNW and 108 and 169 for the SE. One m3 (~535 OD kg wood potion) of LVL stores about 980 kg CO2 equivalents. The amount of carbon stored in LVL thus exceeds total CO2 emissions during manufacturing by about 350%. This study provides the necessary gate-to-gate LVL manufacturing LCI data for the cradle-to-gate LCA to develop an updated EPD.