Life cycle greenhouse gas emissions and energy analysis of prefabricated reusable building modules
Highlights
▸ Modular prefabricated steel, timber and conventional concrete buildings were compared. ▸ An eight-storey, 3943 m2 multi-residential building in Melbourne was investigated. ▸ The life cycle greenhouse gas emission and life cycle energy were quantified. ▸ The potential benefits of reusability of materials were quantified and assessed. ▸ The reductions in the space required for landfill were also quantified.
Introduction
The construction and operation of buildings is responsible for significant environmental impacts, predominately through resource consumption, waste production and greenhouse gas emissions. Treloar et al. [1] have shown the importance of considering the life cycle impacts of buildings, as the environmental impacts of initial construction can be just as significant as those associated with their operation. The construction of buildings generates significant quantities of waste, on average up to 10% of the volume of materials used in constructing the building [2]. A large proportion of this waste goes to landfill where, in Australia, 42% of the total solid waste stream is construction and demolition waste [3]. This is contributing to the rapid depletion and inefficient use of our natural resources and energy and resulting in increased pressure on landfill availability.
Numerous strategies have been adopted in an attempt to improve the efficiencies of construction and reduce waste (design for disassembly, lean construction and waste management). By appreciating the principles of handling and using materials on site, attitudes to prevent waste are being developed and the construction process is beginning to be managed more efficiently [4].
Another strategy for reducing construction waste involves the prefabrication of building components which has also been known to reduce construction costs and time. This involves assembling components of the building in a factory or other manufacturing site, and transporting complete assemblies or sub-assemblies to the construction site where the building is to be located [5], [6]. This practice is in contrast to the more conventional construction practice of transporting the basic materials to the construction site where all assembly is carried out. The prefabrication of buildings has been shown to provide savings in construction waste of up to 52% [7], mainly through the minimisation of off-cuts [8], and can significantly improve the energy, cost and time efficiency of construction.
To reduce life cycle environmental impacts of buildings, their service life should be extended as much as possible [9]. The durability of the structure plays an important role. For example, the structure of commercial buildings in Australia is typically designed to last 100 years; however the average service life of buildings in the Melbourne CBD is closer to 25 years. This figure is based on the observation that most major refurbishments or deconstructions of office buildings in Melbourne happen within the first 20–30 years of the building's life. The life cycle environmental impacts can be significantly reduced if the structural components of a building are designed to be durable and reusable. Innovative design of the structural connections at the initial development stage is extremely important to ensure that the deconstruction/demolition process can take place efficiently to maximise the reusability of building components.
This study aims to quantify the potential life cycle environmental benefits of prefabricated modular buildings in order to determine whether this form of construction provides improved environmental performance over conventional construction methods.
Section snippets
Background
Waste minimisation strategies have been popular for some time in the construction industry. Many studies measure waste from construction sites on the basis of either volume or mass, to gauge the effect on disposal costs [10], [11], [12]. The savings from reducing waste can be best measured in terms of the environment by considering their embodied impacts [13]. For example, embodied energy (i.e. the energy consumed during extraction, processing, manufacturing, and transportation at all stages
Methodology
A multi-residential building has been used as a case study to assess the life cycle energy performance of prefabricated steel and timber constructions. This section outlines the case study building that was analysed and the methods used to assess the life cycle energy requirements associated with both conventional concrete and prefabricated steel and timber construction approaches for this building.
Results and discussion
This section presents the results and discussion of the life cycle energy analysis of the case study building for prefabricated steel and timber, and concrete construction approaches.
Conclusions
This study has assessed the life cycle energy requirements of three forms of construction for a multi-residential building, conventional concrete construction, prefabricated steel construction, and prefabricated timber construction to determine the environmental benefits offered by modularised prefabrications. This comparison used an innovative hybrid embodied energy assessment approach that has never before been used in this manner. The study has shown that the prefabricated steel system
References (54)
- et al.
Quantifying the waste reduction potential of using prefabrication in building construction in Hong Kong
Waste Management
(2009) - et al.
Energy and environmental indicators related to construction of office buildings
Resources, Conservation and Recycling
(2008) Validation of a hybrid life cycle inventory analysis method
Journal of Environmental Management
(2008)- et al.
Net energy analysis: handbook for combining process and input–output analysis
Resources and Energy
(1978) - et al.
Truncation error in embodied energy analyses of basic iron and steel products
Energy
(2000) Input–output analysis: input of energy, CO2 and work to produce goods
Journal of Policy Modeling
(1996)- et al.
Energy embodied in buildings: wood versus concrete
Energy Policy
(2002) - et al.
On the linkage of socio-economic and ecologic systems
Papers in Regional Science
(1968) Input–output analysis and energy intensities: a comparison of methodologies
Applied Mathematical Modelling
(1977)Functions, commodities and environmental impacts in an ecological–economic model
Ecological Economics
(2004)
Approaches to correct for double counting in tiered hybrid life cycle inventories
Journal of Cleaner Production
Life cycle energy and greenhouse emissions analysis of wind turbines and the effect of size on energy yield
Renewable and Sustainable Energy Reviews
Life cycle energy analysis of building integrated photovoltaic systems (BiPVs) with heat recovery unit
Renewable and Sustainable Energy Reviews
Using national input–output data for embodied energy analysis of individual residential buildings
Construction Management and Economics
An analysis of factors influencing waste minimisation and use of recycled materials for the construction of residential buildings
Management of Environmental Quality
Waste Management, Report No. 38
Waste Prevention on Site
Constructability Improvement Using Prefabrication, Pre-assembly and Modularisation
Standardisation and Pre-assembly Adding Value to Construction Projects, Report 176
Architect and contractor attitudes to waste minimisation
Waste and Resource Management
Life cycle greenhouse gas emissions of building and construction: an indicator for sustainability
Cost effective waste minimisation for construction manager
Cost Engineering
Construction waste minimisation for Australian residential development
Asia Pacific Journal of Building and Construction Management
Minimising waste on construction project sites
Engineering, Construction and Architectural Management
Including recycling potential in energy use into the life cycle of buildings
Building Research and Information
Handbook of Industrial Energy Analysis
Building Materials, Energy and the Environment: Towards Ecologically Sustainable Development
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