Universidade de Aveiro Ano de 2017
Departamento de Engenharia Civil
Kamar Aljundi
Is BIM an effective methodology to integrate LCA in
the buildings’ design?
Case study: building of the University of Aveiro
O BIM é uma metodologia fiável para a integração da
ACV no projeto de edifícios?
Universidade de Aveiro Ano de 2017
Departamento de Engenharia Civil
Kamar Aljundi
Is BIM an effective methodology to integrate LCA in
the buildings’ design?
Case study: building of the University of Aveiro
O BIM é uma metodologia fiável para a integração da
ACV no projeto de edifícios?
Caso de estudo: edifício da Universidade de Aveiro
Tese apresentada à Universidade de Aveiro para cumprimento dos requisitos necessários à obtenção do grau de Mestre em Engenharia Civil, realizada sob a orientação científica da Professora Doutora Maria Fernanda da Silva Rodrigues, Professora Auxiliar do Departamento de Engenharia Civil da Universidade de Aveiro e coorientação do Doutor Armando Teófilo dos Santos Pinto, Investigador Auxiliar do Laboratório Nacional de Engenharia Civil.
Apoio financeiro da Plataforma Global de Apoio a Estudantes Sírios.
o júri
presidente Professor Doutor Joaquim Miguel Gonçalves Macedo
professor auxiliar da Universidade de Aveiro
Doutora Ana Cláudia Relvas Vieira Dias
Equiparada a Investigadora Auxiliar da Universidade de Aveiro
Professora Doutora Maria Fernanda da Silva Rodrigues
agradecimentos À minha Orientadora, a Professora Fernanda Rodrigues, à Professora Ana Cláudia Dias, ao Doutor Armando Pinto, à Dr.ª Helena Barroco, a Sua Excelência ex-Presidente da República Dr. Jorge Sampaio, aos meus Professores, ao Projeto Success, à Plataforma Global de Apoio a Estudantes Sírios, à Universidade de Aveiro, à minha família e ao Joaquim.
palavras-chave BIM, ACV, método BIM-ACV, construção sustentável, soluções estruturais,
Revit, SimaPro, Tally.
resumo O setor de construção tem vindo a crescer consideravelmente desde a revolução
industrial, contribuindo para o aumento dos impactes ambientais na Terra, tais como o aquecimento global, smog, e mudanças climáticas. Como tal, são necessários edifícios mais sustentáveis para reduzir esses impactes.
De facto, como a indústria da construção se inicia com a escolha dos materiais a aplicar, a seleção de materiais com menores impactes ambientais e com uma elevada durabilidade são essenciais para alcançar uma construção mais sustentável, particularmente se integrados logo nas fases iniciais de projeto. Durante o século passado, o conceito de sustentabilidade e as suas estratégias desenvolveram-se significativamente, proporcionando à comunidade cientifica e técnica diversas metodologias e sistemas com o intuito de promover edifícios verdadeiramente sustentáveis, tais como ACV, e sistemas de avaliação da sustentabilidade como o BREEAM e o LEED.
Por outro lado, o setor da construção assistiu nos últimos anos a uma revolução tecnológica com a introdução da metodologia Building Information Modelling -BIM. Com efeito, é uma metodologia na qual as especialidades de arquitetura e engenharia estão integradas, podendo ser modeladas e geridas ao mesmo tempo, no mesmo ficheiro e no mesmo ambiente, desde as fases iniciais do projeto. Assim, esta visão mais sistemática e organizada tem a potencialidade de diminuir os erros na fase da construção e da operação.
Este trabalho analisou o edifício do Departamento de Comunicação e Arte da Universidade de Aveiro, que foi concebido como um edifício sustentável do ponto de vista energético. A ACV foi utilizada para calcular os impactes ambientais de três diferentes soluções estruturais (mista, metálica e betão armado), numa perspetiva Cradle-to-Cradle, considerando dois períodos de vida útil: 50 anos e 100 anos. Usaram-se ainda duas abordagens de cálculo: (i) a abordagem tradicional de ACV, usando o SimaPro baseado no modelo BIM-3D; e (ii) o BIM-ACV, usando o Tally e o modelo BIM-3D.
Esta comparação concluiu que existem vários obstáculos na aplicação da ACV no setor da construção, particularmente no que respeita à (in)existência de bases de dados específicas que influenciam os resultados da ACV. Além disso, essas duas abordagens destacaram as potenciais vantagens que a integração da ACV no BIM poderia ter no setor da construção, em geral, e particularmente para a obtenção da construção sustentável.
Concluiu-se, ainda, que a estrutura de betão armado tem menos impactes relativos ao aquecimento global do que as outras que foram também consideradas.
Por fim, este trabalho permitiu evidenciar a necessidade e a potencialidade da integração da ACV no BIM no setor de construção. Adicionalmente, conclui-se que é necessário desenvolver uma base de dados nacional de materiais e de técnicas construtivas, de modo a minimizar os erros e a incerteza dos cálculos da ACV, quer usando a abordagem tradicional LCA ou o BIM-ACV.
keywords BIM, LCA, BIM-based LCA, sustainable construction, structural solutions, Revit, SimaPro, Tally.
abstract The buildings’ sector has been growing since the industrial revolution and
consequently it has been contributing increasingly to the world negative environmental impacts, such as global warming, smog emissions and climate changes. Thus, more sustainable buildings are needed, since it is essential to reduce the negative impacts of the construction sector.
Indeed, since the construction process starts selecting construction materials with less environmental impacts and high durability that are essential to reach more sustainable constructions, particularly when applying it from the early stage of design phase.
During the last century, sustainability concept and strategies have been developed significantly, providing the Scientific and Technical community with various methodologies and systems aiming to promote real sustainable buildings, such as LCA, and labelling and assessing systems like BREEAM and LEED.
On the other hand, the construction and design sectors have recently been facing a new technology revolution with the Building Information Modelling – BIM, approach. In fact, BIM is a methodology in which the architectural and engineering areas can be modelled, cooperated and managed at the same time, in the same file and environment and since the early stages of the design. Thus, BIM provides less errors in the construction and operation phases in a much more organised and systematic approach.
This work analyses the building of Communication and Art Department of the University of Aveiro, which was designed as a sustainable building according the energy efficiency. LCA methodology was used to calculate the environmental impacts of three different structural solutions (mixed, steel and concrete) in a Cradle-to-Cradle perspective, considering two life spans: a 50-year life span and a 100-year one. Throughout this case study, applying LCA in the construction sector was experienced using two approaches: (i) LCA traditional approach using SimaPro and 3D model; and (ii) based LCA using Tally and BIM-3D model.
This comparison showed that there are various obstacles when applying LCA in the construction sector, particularly the (in)existence of specific database, since they influence LCA results. Moreover, those two approaches highlighted the potential advantages that LCA integration with BIM could add to the construction sector, in general, and particularly to sustainable construction.
This study also concludes that the concrete structure has less global warming impacts than the others that were considered.
Finally, this work showed the necessity and the potentiality of integrating LCA in BIM in the construction sector. In addition, it concludes the need to develop a national database of construction materials and techniques that could minimise the errors and the uncertainty of LCA calculations whether using LCA traditional approach or BIM-based approach.
i
Index
Index ... i
Index of figures ... iii
Index of tables ... v
List of symbols ... vii
1. Introduction ... 1
1.1. Framework ... 1
1.2. Hypothesis of the dissertation ... 5
1.3. Objectives and work methodology ... 5
2. LCA and BIM in the Sustainable construction ... 7
2.1. Introduction ... 7
2.2. Sustainable construction ... 7
2.3. Life Cycle Assessment ... 11
2.4. Building Information Modelling ... 21
2.5. Chapter synthesis ... 36
3. Literature Review ... 39
3.1. Introduction ... 39
3.2. LCA studies in buildings ... 39
3.3. LCA in structural solutions ... 50
3.4. Integration LCA in BIM ... 54
3.6. Chapter synthesis ... 59
4. Case study building ... 61
4.1. Introduction ... 61
4.2. Characterization of the case study ... 61
4.3. Work Methodology ... 63
4.4. Inventory analysis of alternative solutions ... 64
4.5. Life Cycle Assessment ... 78
4.6. Chapter synthesis ... 88
5. LCA results interpretation phase ... 89
5.1. Introduction ... 89
5.2. Work Results ... 89
5.3. Discussion of results ... 107
5.5. Chapter synthesis ... 119
6. Conclusions and Further Researches ... 121
6.1. Conclusions ... 121
6.2. Future work and further researches ... 127
References ... 129
Annexes ... 143
List of annexes ... 143
Annex I – Design drawings of case-study ... 145
Annex II – Structural calculations justifying the work ... 157
Annex III – Revit design drawings ... 165
iii
Index of figures
Figure 1 - World population growth between 1750 and 2100 (Roser and Ortiz-Ospina, 2017) ... 1
Figure 2 - Evolution of CO2 concentration in atmosphere (WWF, 2016) ... 2
Figure 3 - Framework of sustainable construction ... 9
Figure 4 - LCA evolution (adapted from Icca, 2013) ... 12
Figure 5 - Types of Process-Based LCA Methods, adapted from, (Bayer et al., 2010) ... 13
Figure 6 - LCA steps and types (PE International, 2010) ... 13
Figure 7 - LCA methodology, according to ISO 14040 and ISO 14044 ... 14
Figure 8 - LCA methodology in construction (Bragança et al 2010) ... 18
Figure 9 – Life cycle assessment stages and types of methods according to the final product (adapted from (Ariyaratne and Moncaster, 2014)) ... 18
Figure 10 - A Visual Representation of BIM Concept (Azhar et al., 2015) ... 22
Figure 11 - Maturity levels of BIM (BIWG, 2011) ... 24
Figure 12 - The maturity that is needed to be achieved in level 3 ... 25
Figure 13 - LOD specification 2016 (Reinhardt and Bedrick, 2016) ... 27
Figure 14 - Hierarchy of BIM tools, platforms in BIM environment ... 27
Figure 15 - Integration of BIM and Building Performance Analysis Software (Courtesy of Holder Construction Company, Atlanta, GA) ... 29
Figure 16 - Global perspective of BIM implementation throughout the world (adapted from (Falcão Silva et al., 2016)) ... 31
Figure 17 - Proposed integrated BIM - sustainable data model (Ilhan and Yaman, 2016) ... 35
Figure 18 - BIM technology improves the quality of construction industry and contributes in sustainable design (Wiley, 2011) ... 36
Figure 19 - WPC LCA studies in residential and commercial buildings (source: Scopus database)41 Figure 20 - Schematic representation of BMCC and WPC groups of LCA studies (Ortiz et al., 2009) ... 42
Figure 21 - Scopus statistics of LCA publications in buildings around the world (source: Scopus database) ... 43
Figure 22 - LCA publications in buildings in different countries (Source: Scopus database) ... 44
Figure 23 - LCA publications' increment in Portugal regarding the buildings sector (source: Scopus database) ... 47
Figure 24 - BIM and LCA studies increment (source: Scopus database) ... 55
Figure 25 - Building location in Aveiro University Campus de Santiago, Portugal (coloured in red) 62 Figure 26 – Revit model of Alternative 1 (real case-study building) ... 66
Figure 27 - Scheme of a HD section ... 71
Figure 28 - Steel alternative model developed in Revit ... 72
Figure 29 – Only reinforced concrete model created by Revit ... 75
Figure 30 - LCA summary scheme of Alternative 1.1 ... 80
Figure 31 - LCA summary scheme of Alternative 1.2 ... 81
Figure 32 - LCA summary scheme of Alternative 2.1 ... 81
Figure 33 - LCA summary scheme of Alternative 2.2 ... 82
Figure 34 -LCA summary scheme of Alternative 3.1 ... 82
Figure 35 - LCA summary scheme of Alternative 3.2 ... 83
Figure 36 - Differences of the ozone depletion impact category between SimaPro and Tally ... 112
Figure 37 - Differences of the global warming impact category between SimaPro and Tally... 113
Figure 38 - Differences of the summer smog impact category between SimaPro and Tally ... 114
Figure 39 - Differences of the acidification impact category between SimaPro and Tally ... 115
Figure 40 - Differences of the eutrophication impact category between SimaPro and Tally ... 116
Figure 41 - Global CO2 eq emissions when only 50% or 25% of concrete nominal cover needs maintenance in the 50-year life span design period... 117
Figure 42 - Global CO2 eq emissions when only 50% or 25% of concrete nominal cover needs maintenance in the 100-year life span design period ... 118
v
Index of tables
Table 1 - Global construction sector impacts (adapted from (Menoufi, 2011)) ... 2
Table 2 - Levels of development (sources: (Reinhardt and Bedrick, 2016) and (SRINSOFT, 2017)) ... 25
Table 3 - Common and major BIM tools and applications adapted from (Wiley, 2011) ... 28
Table 4 - Examples of BIM stages around the world (data taken from (Falcão Silva et al., 2016)) . 31 Table 5 - Examples of LCA studies for the first group (BMCC) ... 40
Table 6 - Examples of LCA studies in buildings ... 42
Table 7 - LCA in buildings publications per populations (sources: Scopus and Worldometers databases) ... 44
Table 8 - LCA in buildings publications per Land Area (source: Scopus and Worldometers database) ... 45
Table 9 - Examples of recent LCA studies applied in building sector in Portugal ... 47
Table 10 - Studies of integration LCA in BIM with their potentialities and limitations ... 56
Table 11 - Description of alternative solutions assessed ... 64
Table 12 – Structural materials’ quantities of Alternative 1.1 ... 66
Table 13 - Reinforcement quantities based on CYPE estimation ... 67
Table 14 – Maintenance and refurbishment actions of Alternative 1.1 ... 68
Table 15 - Concrete volume that needs to be added in the 100 years’ life span design (Alternative 1.2) ... 69
Table 16 - Maintenance and refurbishment actions of Alternative 1.2 ... 70
Table 17 - Structural materials’ quantities of Alternative 2 ... 72
Table 18 - Maintenance and refurbishment actions of Alternative 2.1 ... 73
Table 19 - Concrete volume that needs to be added in the 100 years’ life span design (Alternative 2.2) ... 74
Table 20 - Maintenance and refurbishment actions of Alternative 2.2 ... 74
Table 21 - Equivalent concrete columns sections ... 76
Table 22 - Equivalent concrete sections in the Alternative 3 ... 76
Table 23 - Quantities of structural materials of the Alternative 3 ... 77
Table 24 - Quantities of concrete that must be added in Alternative 3.2 ... 77
Table 25 - Quantity of nominal cover layer needing substitution in Alternative 3 ... 78
Table 26 - Material description in SimaPro and Tally... 86
Table 27 - Calculation method of life cycle impact assessment ... 88
Table 28 - Embodied environmental impacts per material by SimaPro ... 90
Table 29 - Embodied environmental impacts per material by Tally ... 90
Table 30 - Global environmental impacts per material using SimaPro in Alt.1.1 ... 91
Table 31 - Global environmental impacts per material using Tally in Alt.1.1 ... 92
Table 32 - Life cycle impacts per phase in Alternative.1.1 calculated by SimaPro ... 93
Table 33 - Life cycle impacts per phase in Alternative 1.1 calculated by Tally ... 93
Table 34 - Global environmental impacts per material using SimaPro in Alt.1.2 ... 94
Table 35 - Global environmental impacts per material using Tally in Alt.1.2 ... 95
Table 36 - Life cycle impacts per phase in Alternative1.2 calculated by SimaPro ... 96
Table 37 - Life cycle impacts per phase in Alternative1.2 calculated by Tally ... 96
Table 38 - Global environmental impacts per material using SimaPro in Alt.2.1 ... 97
Table 39 - Global environmental impacts per material using Tally in Alt.2.1 ... 97
Table 40 - Life cycle impacts per phase in Alternative.2.1 calculated by SimaPro ... 98
Table 41 - Life cycle impacts per phase in Alternative.2.1. calculated by Tally ... 99
Table 42 - Global environmental impacts per material using SimaPro in Alt.2.2. ... 100
Table 43 - Global environmental impacts per material using Tally in Alt.2.2. ... 100
Table 44 - Life cycle impacts per phase in Alternative2.2 calculated by SimaPro ... 101
Table 45 - Life cycle impacts per phase in Alternative2.2 calculated by Tally ... 101
Table 46 - Global environmental impacts per material using SimaPro in Alt.3.1 ... 102
Table 47 - Global environmental impacts per material using Tally in Alt.3.1 ... 102
Table 48 - Life cycle impacts per phase in Alternative.3.1 calculated by SimaPro ... 103
vi
Table 50 - Global environmental impacts per material using SimaPro in Alt.3.2 ... 104
Table 51 - Global environmental impacts per material using Tally in Alt.3.2 ... 104
Table 52 - Life cycle impacts per phase in Alternative.3.2 calculated by SimaPro ... 105
Table 53 - Life cycle impacts per phase in Alternative.3.2 calculated by Tally ... 105
Table 54 - Total environmental impacts in each alternative regarding each impact category ... 106
Table 55 - Total environmental impacts per area (m2) ... 107
Table 56 - Differences between Alt.1.1 and Alt.1.2 impacts calculated using SimaPro and Tally . 109 Table 57 - Differences between Alt.2.1 and Alt.2.2 impacts calculated using SimaPro and Tally . 110 Table 58 - Differences between Alt.3.1 and Alt.3.2 impacts calculated using SimaPro and Tally . 110 Table 59 - Differences of ozone depletion impact category between SimaPro and Tally ... 111
Table 60 - Differences of the global warming impact category between SimaPro and Tally ... 112
Table 61 - Differences of the summer smog impact category between SimaPro and Tally ... 113
Table 62 - Differences of the acidification impact category between SimaPro and Tally ... 114
Table 63 - Differences of the eutrophication impact category between SimaPro and Tally ... 115
Table 64 – Global CO2 eq emissions when only 50% or 25% of concrete nominal cover needs maintenance in the 50-year life span design period... 117
Table 65 - Global CO2 eq emissions when only 50% or 25% of concrete nominal cover needs maintenance in the 100-year life span design period ... 118
Table 66 - Coefficient Kσ values ... 159
Table 67 - Pre-structural design of beams in Alternative3 ... 162
Table 68 - Pre-design of slabs' thickness in Alternative 3 ... 163
vii
List of symbols
2D – two dimensions 3D – three dimensions
AEC – Architecture, Engineering and Construction BIM – Building Information Modelling
BMCC – Building Material Component Combination
BREEAM – Building Research Establishment Environmental Assessment Method CAD – Computer Aided Design
CO2 – Carbon Dioxide
CFC – Chlorofluorocarbon eq – equivalent emission of GHG – Greenhouse Gases
HVAC – Heating Ventilation and Air Conditioning ISO – International Organization for Standardization IFC – Industry Foundation Classes
IFD – International Framework for Dictionaries LCA – Life Cycle Assessment
LCC – Life Cycle Cost LCI – Life Cycle Inventory
LCIA – Life Cycle Impact Assessment
LNEC – Portuguese Civil Engineering National Lab (Laboratório Nacional de Engenharia Civil) LOD – Level of detail
LOI – Level of Information
LEED – Leadership in Energy and Environmental Design MEP – Mechanical Electrical and Plumbing
viii MTO – Material Take-Off
N.A. – Not Applicable NOx – Oxides of Nitrogen
O3 - Ozone
SO2 – Sulphur Dioxide
UK – United Kingdom
USA – United States of America WPC – Whole Process Construction
1
1. Introduction
1.1. Framework
The industrial revolution, which took place in the 18th and the 19th centuries, was characterized by
variety of challenges and changes in the world. This revolution has transformed the manufacturing from a simple scale in people’s homes, using hand tools or basic machines, to a powered special-purpose machinery, factories and mass production (Ford and Despeisse, 2016).
On the other hand, after the industrial revolution the global population growth rate started increasing from 0.6% and only stopped increasing in 1970s with a maximum pick point of 2.1% per year. Consequently, the actual world population is 7.4 billion people. Although the growth rate is decreasing, the population is still expected to grow until 11.2 billion until 2100 (see Figure 1).
Figure 1 - World population growth between 1750 and 2100 (Roser and Ortiz-Ospina, 2017) The global growth population allied with the new needs and exigencies that industrial revolution has created have contributed to a large impact in the environment to a level that the planet never faced (Faucheux et al., 1998).
The actual world ecological footprint is an example of the consequences of these impacts and it has been reported that the bio-capacity needed to provide the natural resources and humanity services consumption is reaching 1.6 planets in 2012 and it is still increasing (WWF, 2016).
2 Moreover, the human impact on the Earth also contributed to increment the atmospheric CO2
concentrations, as it can be seen in Figure 2. As an effect, the temperature of the Earth has also started increasing after the industrial revolution with future consequences to the planet which are still unpredictable and could affect massively the humanity (Gore, 2006).
Figure 2 - Evolution of CO2 concentration in atmosphere (WWF, 2016)
On the other hand, the global growth of the population and the consequent increase of migration into urban areas have enlarged the pressure on construction sector in order to respond to the need of new houses, schools, and other infrastructures (Sharma et al., 2011).
However, buildings construction has brought bigger consuming of resources and power, which are needed to produce the materials and to operate these buildings (Peng and Wu, 2015). In fact, Table 1 shows that the construction sector represents 40% of the final energy consumption. From this energy, the manufacture of building materials contributes to approximately 10% of all global energy end-use (Wong and Zhou, 2015).
Table 1 - Global construction sector impacts (adapted from (Menoufi, 2011)) Worldwide Impacts
Energy 40%
CO2 emissions 32%
Raw materials extraction 24%
On the other hand, construction processes (e.g. concrete production) have resulted in a large waste production of unrecyclable materials (Aprianti, 2015). Table 1 also shows that this sector has also important environmental impacts regarding the extraction of raw materials and CO2 emissions, facts
that largely contribute to the high world ecological footprint described before.
Therefore, one of the actual challenges of the construction sector is to respond to the increasing of the most demanding population needs in such a way that it can reduce its negative environmental effects and make it more efficient and sustainable (Antón and Díaz, 2014a).
3 It is in this context of a continuous increasing of environmental impacts on the planet, that the sustainable development concept was defined, in 1987, consisting on what the community can do to improve the quality of life without compromising the needs of the next generations. Thus, sustainable development could be achieved where the population growth is in harmony with the changing productive potential of the ecosystem, (Brundtland, 1987).
As far as construction sector is concerned, sustainability can also be achieved when the concept of sustainable construction is adopted. Sustainable Construction was first defined by Charles Kibert (1994) as being “the responsible development and management of a healthy built environment, based on the efficient use of the resources and on the ecological principles” (Kibert, 1994).
Therefore, managing and controlling the environmental influence of the construction must be leaded with assessment tools and sustainability criteria method and by involving the stakeholders in the development process. This will allow to create more resilient and sustainable built environment since the conceptual design phase of the building till the end of its life cycle (Schmidt and Osebold, 2017). Civil engineers and Architects are one of the players of all the stakeholders who have the major responsibility to implement sustainability in their designs and their projects in order to seek the sustainable construction, defined above, and to reflect positively on the environment and on the quality of life (Tah et al., 2016).
For instance, Building Performance Modelling (BPM) has been a current example about the sustainable design that engineers are improving. BPM is used to sustain the design through running daylight analysis, artificial light visual simulation, visual impact studies and environmental cost impact analysis as these enhance its significant (Oduyemi et al., 2016).
Cooperating with the International Organization for Standardization (hereafter ISO), the developers and researchers have created Life Cycle Assessment (hereafter LCA) which is a methodology to implement sustainability and to reach the least possible consume of energy, extract of resources and waste and emissions production through the entire construction life cycle (Pinheiro et al., 2006). LCA is used to predict the environmental impact of products and goods (e.g. energy, CO2 emissions,
materials and waste) during the entire cycle of the product. Construction materials are a specific example of the products the LCA could study and analyse (Menoufi, 2011).
Recently, LCA has been able to analyse the impacts of the entire building life cycle on the nature, considering it as a product produced through many processes within the following phases: (i) design; (ii) construction; (iii) operation; (iv) demolition; and (v) disposal or recycle it again to enter in another life cycle (Sharma et al., 2011).
So forth, in order to reach a sustainable construction, the following steps should be foreseen (Jalaei and Jrade, 2015):
4 Create sustainable sites and working places;
Take care of the water efficiency using suitable equipment and resilience strategy; Analyse and control the energy needed;
Enhance the quality of the indoor environment; Innovate the design process.
It is important to act in the design phase to decrease the impacts of all phases from the beginning. This can allow to improve the efficiency of the operation phase, which represents a large portion of the buildings’ environmental impacts (de Klijn-Chevalerias and Javed, 2017).
In the conceptual design phase, it is necessary to consider the material processing and components manufacturing since they contribute to 70-90% of the embodied energy and other environmental impacts, such as global warming, acidification potential and greenhouse emissions (Huang et al., 2015). LCA can be used to predict the environmental impact of these processes and the construction materials in order to find the solutions with the lowest environmental impacts (Fischer et al., 2013). LCA is a method that can be used to decide about more sustainable materials and solutions with less environmental impacts, also achieving buildings with better quality of life (Crawford et al., 2014). In fact, energy savings could approach 50% and the decrease of the carbon emissions could reach 30% if the construction materials were carefully selected (Pullen et al., 2015) and (Vanegas et al., 1995).
In parallel with all the previous issues, during the last decades, the world has faced a new data revolution with the appearance of computers, internet and all the new technologies that are still being developed, such as artificial intelligent, among others, which are reformulating the way the human beings are facing and solving their problems (Zheng et al., 2012).
As far as the construction sector is concerned, this data revolution has contributed to produce the methodology of Building Information Modelling (BIM). BIM’s tools and interfaces are enriching the construction industry with new prospects and chances to implement more sustainable and resilient buildings (Wiley, 2011).
The basic principle of BIM is generating and managing a 3D model with information and material properties. This model can help calculating, for instance, the cost, the energy, the structural analysis or the Mechanical Electrical Plumbing analysis (hereafter MEP) (Rahmani Asl et al., 2015). Those analyses can be done during the conceptual design and before implementing the project (Cohn, 2007) and (Wiley, 2011).
This concept of BIM intersects with the concept of LCA and Life Cycle Cost (hereafter LCC), which aim to calculate the environmental impacts and the costs of the products (e.g., a building) during their entire life cycle in the decision-making phase before manufacturing the products. Thus, BIM
5 could be a facility to help using LCA in the recent future to reach more sustainable constructions (Vaiciunas et al., 2015) and (Eleftheriadis et al., 2017).
1.2. Hypothesis of the dissertation
Applying LCA in many countries, and especially in Portugal, is facing various obstacles related to the lack of information and database. To search in analysing these difficulties, this work is applying LCA in buildings using two LCA tools (a traditional one and a BIM one), emphasising how BIM can handle building LCA in a straightforward way, with the same quality of detailed LCA tools.
Therefore, this dissertation hypothesis is that BIM can facilitate applying LCA in the construction sector, particularly since it can provide LCA methodology with the required information and database with less time-consuming process and achieve more sustainable solutions in the construction sector. 1.3. Objectives and work methodology
As described before, this study will discuss how LCA can be integrated with BIM to reach more sustainable building and minimising the negative influences on the environment, starting from the conceptual design phase, where it is possible to analyse the design and the alternatives with the least cost and time.
Therefore, the first objective is to determine whether BIM is being used as a methodology to seek more sustainable constructions and if it is used by designers to endorse the using of LCA methodology, which is discussed in the Literature Review.
After the theoretical approach, BIM is used to model a real case study building with different structural solutions, such as concrete and steel, and extract the quantities from the 3D model.
For this analysis, the traditional LCA approach will be implemented and compared with BIM-based LCA approach in order to investigate whether BIM is a practical and reliable methodology in achieving more sustainable structures by doing BIM-based LCA calculations and predict the environmental impact of these materials.
This case study analysis allows taking advantage of all the potentialities of BIM, which have proved to be very important to decide about the use of more green building materials that could be applied in the current construction industry seeking for more sustainability, in a competitive and less time-consuming design phase.
Therefore, the thesis is organised beginning with the 1st chapter (Introduction), where the framework
is done, the hypothesis of the dissertation is formulated and also has a section to explain how the work is organised. This chapter consists of an introduction about the global concern toward the population growth rate and its consequences on the environment, in addition to the need of sustainable design to achieve sustainable construction and so forth sustainable environment.
6 In the 2nd chapter (LCA and BIM Methodologies), the theoretical concept of LCA with its principles
ISO 14040-14044 is explained, taking into account the advantages and the limitations of LCA. Furthermore, the importance of LCA in the construction sector and in choosing more sustainable structural materials is highlighted. On the other hand, BIM methodology is here described; using BIM in sustainable design is also emphasised to figure out the possibilities of integration these two methodologies since they have the sustainability objective in the design and the environment. The 3rd chapter (Literature Review) concludes the state of the art of the studies and researches done
in this domain to investigate the questions which have presented in the previous chapters, demonstrating whether using BIM can facilitate calculating LCA in buildings in a theoretical approach. The following chapter is the 4th Case Study, which describes and characterises the building and the
selection process of its materials according to the justifications in the 3rd chapter. LCA is then
calculated regarding these materials and other boundaries that are selected to achieve more sustainable selection and modification of the structural materials. Regarding BIM application, in this chapter the 3D model is pursued and described to extract the information and the quantities that is needed to calculate LCA of the materials in the case study.
After running the calculation and the simulation using LCA software (SimaPro) and by BIM interface (with Autodesk Revit® software) in the 4th chapter, the 5th chapter Results and Discussion represents
the results and discusses them analysing the assumptions of the first three chapters.
Finally, the 6th chapter Conclusions and Further Researches discusses the veracity of hypothesis,
and also highlights some recommendations and limitations that this study has faced during the entire work. Moreover, it will discuss the needed further researches and future works.
7
2. LCA and BIM in the Sustainable construction
2.1. Introduction
As it was enlightened in the previous chapter, the global increase of the industrial and technological products has caused various environmental impacts that cannot be ignored, especially in the construction sector, which contributes to a large portion of these negative impacts on the environment.
In this chapter, the main concepts that will be used throughout the work will be defined and the relationship between them will be explained. Therefore, there is a first part dedicated to sustainable construction, as an imperative target of architecture and civil engineering sector. A second part dedicated to Life Cycle Assessment (LCA), as a methodology that has important role to achieve the sustainability’s objectives. Finally, the Building Information Modelling (BIM) concept is explored, since it could be seen as a tool that integrates LCA with all the specialities and designs of the construction, helping to allow reaching more sustainable solutions.
2.2. Sustainable construction
In the previous chapter, it was highlighted the concept of sustainability and how important is its adoption in order to reduce the impacts of the construction industry on the planet. When sustainability is applied to construction, it is called sustainable construction, which was first defined by Charles Kibert as “the responsible development and management of a healthy built environment, based on the efficient use of the resources and on the ecological principles” (Kibert, 1994).
In fact, the sustainable construction is a subset of sustainable development, which addresses the role of the built environment in contributing to the overarching of sustainability within the ecological, social and economic issues of a building in the context of its community (Kibert, 2016b). A summary of the objectives of these three issues is presented as follows (Tirone and Nunes, 2008):
Environmental issues – a sustainable building should consider an efficient use of the natural resources and a low emission of pollutants and effluents, never compromising the healthy and comfortable characteristics of the construction. Therefore, it should consider energy efficient solutions, with low embodied energy and low CO2 emissions, water efficient systems, low impact
materials, using more recycled materials, and reducing the waste of materials among all the other aspects that should be considered during the design phase in order to reduce the pressure of the building in the environment.
Social issues – the building should be a comfortable and healthy place designed for long use term. Thus, aspects like thermal indoor comfort, acoustic comfort, indoor daylight comfort, the use of materials with low toxicity to human beings should always be considered. Moreover, the architecture should be designed regarding the flexibility of indoor spaces that will allow the
8 building’s future adaptation to other uses, different from its first use, helping further refurbishment projects and so forth reducing the environmental impacts.
Economic issues – all the social and the environmental aspects should be designed bearing in mind an economic viewpoint reducing building costs, especially in life cycle cost perspective. Therefore, a sustainable building should have lower life cycle costs than a normal one.
The previous three aspects highlight how complex it is to implement a real sustainable construction considering all the sustainability key points. A summary of the main principles that should be considered in a sustainable design is listed as follows (Kibert, 1994), (Pinheiro, 2010) and (Bragança and Mateus, 2006)
Reduce resources consumption;
Increase the efficiency (of energy, water and resources); Reuse resources;
Use low environmental impact solutions; Use recyclable materials;
Protect nature; Eliminate toxics; Focus on Quality;
Focus on indoor comfort (e.g., thermal, acoustic, lighting);
Promote a local dynamic and a proper integration of the building in the community; Promote an environmental and innovative management of the built environment; Apply life-cycle costing.
Figure 3 presents the framework that articulates how the built environment could contribute in the attainment of sustainable construction (Kibert, 2016b).
9 Figure 3 - Framework of sustainable construction
Consequently, a sustainable construction requires many techniques to deal with all the previous aspects during all its lifecycle phases. Moreover, there is not a simple strategy to perform a sustainable building, since achieving a sustainable construction requires a decision that collects the environmental, social and economic criteria (Poveda and Young, 2015).
Therefore, achieving a sustainable construction calls the need to create systems that consider all those criteria with specific indicators that allow quantifying all the aspects of the sustainability building performance (Jawali and Fernández-Solís, 2008).
Building Research Establishment Environmental Assessment Method (BREEAM) was the first of these systems and was launched in 1990 in UK. It is a sustainability assessment method for master planning projects, infrastructure and buildings and addresses several lifecycle stages. Thus, BREEAM is divided in ten groups of criteria which are: (i) energy; (ii) health and wellbeing; (iii) innovation; (iv) land use; (v) materials; (vi) management; (vii) pollution; (viii) transport; (ix) waste; and (x) water (BREEAM, 2017).
All those systems aim to assess all the issues of a sustainable construction by measuring the performance of all the criteria and giving a quantifiable classification for each criterion. Each one has its own weight contributing to the final classification of the building’s sustainability index. Thus, they turned this certification process into a measurement process of many criteria allowing to quantify and to evaluate the sustainability of the building, helping designer to choose the most appropriate strategy to each construction. At the same time, they are associated with certification labels that can
10 differentiate sustainable buildings from common ones and then increase market demand for the sustainable construction (Kibert, 2016a).
As far as these techniques and systems need to fit each building, these systems vary from community to another and from country to another, where the buildings are adapted to their users’ needs, their local climate and region characterisations. And after creating the British sustainability system, the other parts of the globe started to create their own systems according to their requirements, countries, and their comfort needs (Poveda and Young, 2015).
So forth, for instance, in USA, Leadership in Energy and Environmental Design rating system (LEED) was created by the U.S. Green Building Council (USGBC), aiming to achieve sustainability in the built environment in the United States of America (LEED, 2017). This system includes six key-points that are essential to reach a sustainable built environment, which are: (i) sustainable sites; (ii) water efficiency; (iii) energy and atmosphere; (iv) material selection; (v) indoor environmental quality; and (vi) innovation and design process. Therefore, this rating system is a reliable measure of how a building could influence the environment (Jalaei and Jrade, 2015).
In Portugal, the LiderA system is based on the concept of repositioning the environment in the construction, in the perspective of sustainability, assuming itself as a system to lead by the environment. The proposed system has three levels: (i) strategic (from idea to plan); (ii) project management and (iii) life cycle management, in order to allow the follow-up in the different phases of development of the life cycle of the building (LiderA, 2013).
Like in LEED, the criteria of LiderA are organised in six principle groups, which are: (i) local integration; (ii) resources; (iii) environmental pollution; (iv) indoor comfort; (v) social economic aspects; and (vi) environmental management and innovation (Pinheiro, 2010).
On the buildings’ viewpoint, these systems that concentrate on evaluating the sustainability and quantifying the environmental impacts, need LCA methodology. Actually, LCA is able to quantify the environmental impacts of the construction materials, the components and the operations as a micro-assessment level of the construction (Ferreira, 2010) and (Jalaei and Jrade, 2015).
Since these materials are required to create and operate the sustainable construction, they must undergo to sustainability systems principles throughout its entire life cycle. This should start since the design phase in order to help figuring out better sustainable solutions and achieving sustainable performance of the entire building as a macro-assessment level (Jalaei and Jrade, 2015).
11 2.3. Life Cycle Assessment
2.3.1. Life Cycle Assessment Evolution
In the late 1960s/early 1970s during the oil crisis, the energy costs increased considerably and companies were struggling to decrease as much as possible their energy bills and find out energy-efficient alternatives to help them overcome their crisis by finding more economical solutions and products (Icca, 2013).
This energy efficiency needs with the initial consciousness of all the environmental impacts on the world described before, awaked the Mankind to be aware of its behaviours and its impacts on the environment. But naturally, the first environmental assessment method (which could be considered as the precursor of LCA) started as a simple calculation of product energy requirements (Meadows et al., 1972).
For instance, the first who has published reports in this domain was Harold Smith who reported his calculation of cumulative energy requirements for the production of chemical intermediates and products at the World Energy Conference in 1963 (Randers, 1972).
As far as buildings consume a noticeable portion of energy, they largely contribute to the world energy demand and greenhouse gases emissions. Particularly when buildings are over 75 years of life span, they contribute to 69-83% of the primary energy requirements and GHG emissions (Bastos et al., 2014). Therefore, GHG emissions started to be calculated and considered to reach better built environment and to reduce the negative environmental impacts of the building sector (Icca, 2013). These calculations became a methodology with standards and principles called Life Cycle Assessment (LCA). In fact, the International Organization for Standardization (ISO) has set the principles and framework of the LCA analysis in the ISO 14040. The ISO 14044 is normalising and regulating the requirements and guidelines of this analysis (ISO, 2006a) and (ISO, 2006b).
Meanwhile, the use of LCA method has been adjusted and extended to include the calculation and analysis of the environmental impacts of construction projects, LCA method requires a large amount of information and inputs of materials and all constructive components and systems. Consequently, this methodology can put obstacles in the process of applying LCA in the construction industry processes (Coelho and de Brito, 2012).
Therefore, it would be a big step in improving attainment LCA in construction once it is integrated within Building Information Modelling (BIM), which can digitally represent the project’s physical and functional characters. By integrating life cycle assessment with BIM, the technology can assist clients, designers and other infrastructure stakeholders in evaluating and understanding the environmental impacts of infrastructure projects at the concept and preliminary design stage (Wang et al., 2016). Figure 4 summarizes all the phases of the LCA improvement described above.
12 Figure 4 - LCA evolution (adapted from Icca, 2013)
2.3.2. LCA methodology
ISO 14040:1998 defines LCA as a “compilation and evaluation of the inputs, outputs and the potential environmental impacts of a product system throughout its life cycle”. Moreover, it defines life cycle as a “consecutive and interlinked stages of a product system, from raw material acquisition or generation from natural resources to final disposal” (ISO, 2006a).
Therefore, LCA is a methodology that provides costumers/users or experts with the requirements (e.g. water and energy) and environmental impacts that are needed to produce (and use) the products during a period of time, specified by the system (Finnveden et al., 2009).
One of the first things to be determined in a LCA analysis is the definition of the system boundary, since it will influence the calculation method itself and consequently the final results. It is usually organized according to the following types (Bayer et al., 2010) and (PE International, 2010): a. Cradle-to-gate: From the extraction of the raw materials to the factory gate; thus, it defines the environmental impact of the production process of the products (the called embodied impacts of the materials/products).
b. Cradle-to-grave: From raw material extraction through product use and disposal. In this way, it includes all the environmental impacts that exist during all the processes of the life cycle, such as extraction, production of needed materials, transportation, operational and use of materials and the final disposal of the product.
c. Gate-to-Gate: Includes the processes from the production phase only; used to determine the environmental impacts of a single production step or process.
d. Gate-to-Grave: These boundaries constrain the process after the production process, starting with the use phase of the product (after the “gate” of the factory) and ending with the disposal. Hence, this type is used to comprehend the impacts of the products once it exits the factory.
e. Cradle-to-Cradle: It includes all the processes of the life cycle, such as extraction, production of needed materials, transportation, operational and use of materials maintenance or refurbishment, allowing the product to inter a new life cycle.
Sustained Building by BIM&LCA 2016 Life Cycle Assessment 2000 Greenhouse Assessment 1990 Resource Analysis 1980 Energy Analysis 1970
13 Figure 5 summarizes these four types of system boundaries and Figure 6 shows the relationship between the four types of LCA and its steps.
Figure 5 - Types of Process-Based LCA Methods, adapted from, (Bayer et al., 2010)
Figure 6 - LCA steps and types (PE International, 2010)
The types of LCA to use in each study/project is also determined regarding the objective of the LCA, whether it aspires to comprehend the environmental effect of the raw materials, intermediate components or the final product (Ariyaratne and Moncaster, 2014).
After defining the system boundaries, ISO 14040 and ISO 14044 stipulate four mandatory steps that should be done to correctly accomplish the LCA methodology, which are listed as follows:
Goal and scope definition; Inventory Analysis;
Life cycle impact assessment; Interpretation of results.
14 These four steps are correlated in Figure 7, which also shows the correspondent chapters of ISO 14044 that explain each one. After it, each step is briefly described in a particular section.
Goal definition:
The goal definition aims to determine the objectives of the LCA, which must consider (ISO, 2006b): The intended application of the LCA study;
The purpose of the LCA study;
The intended audience of the LCA report; The use for comparative analysis.
Scope definition:
The scope definition aims to characterise the product and the process, defining: (i) a functional unit; (ii) the function of the product; (iii) the reference flow; (iv) the system description and boundaries; (v) the allocation procedure; (vi) quality data requirements (QDR) and assumptions; (vii) limitations; and (viii) peer review and reporting type (PE International, 2010).
The functional unit is defined in ISO 14040 as the “quantified performance of a product system for use as a reference unit” and shall be consistent with the goal and scope of the study. It provides a reference to which the input/output data are normalized (in a mathematical sense). Therefore, the functional unit shall be clearly defined and measurable. Comparisons between systems shall be made on the basis of the same function(s), quantified by the same functional unit(s) in the form of their reference flows (ISO, 2006a).
Inventory analysis:
It is also called as Life Cycle Inventory and denoted as LCI. It consists of data collection and emissions of resources needed in the process (e.g. manufacturing and packaging of a product). LCI involves collecting data for each unit process, regarding all relevant inputs and outputs of energy and
Goal definition (Chapter 4.2 of ISO 14044) Scope definition (Chapter 4.2 of ISO 14044) Inventory Analysis (Chapter 4.3 of ISO 14044) Impact Assessment (Chapter 4.4 of ISO 14044) Interpretation (Chapter 4.5 of ISO 14044)
15 mass flow, as well as data on emissions to air, water and land, and all the other relevant environmental impacts. This phase also includes calculating both the material and the energy input and output of the system throughout all its life (ISO, 2006b) and (PE INTERNATIONAL, 2010). Life cycle impact assessment:
Denoted as life cycle impact assessment (LCIA), it is a technique that concerns about achieving the goal and the scope of the life cycle assessment. The LCIA consists of mandatory and optional elements. The mandatory elements are the following ones:
Selection of impact categories, category indicators and characterization models; Assignment of LCI results to the selected impact categories (classification); Calculation of category indicator results (characterization).
On the other hand, the optional elements of LCIA are listed as follows:
Calculation of the magnitude of category indicator results relative to reference information (normalisation);
Grouping; Weighting.
In a life cycle impact assessment (LCIA), there are essentially two methods: Problem-oriented methods (mid-points);
The damage-oriented methods (end points).
The mid-points approach involves the environmental impacts associated with climate change, commonly: acidification, eutrophication, potential photochemical ozone creation and human toxicity. The impacts can be evaluated using methods, such as Centre of Environmental Science (CML) baseline method (2001) (Reiter, 2010).
The so-called CML method is the methodology of the Centre for Environmental Studies (CML) of the University of Leiden and focuses on a series of environmental impact categories expressed in terms of emissions to the environment. The CML method includes classification, characterization, and normalisation (PE International, 2010).
The Tool for the Reduction and Assessment of Chemical and other Environmental Impacts (TRACI) is another method used in the mid-points approach. This method is developed by the U.S. Environmental Protection Agency (EPA) and is primarily used in the US (PE International, 2010). The end-points approach classifies flows into various environmental themes, modelling the damage that each theme causes to human beings, natural environment and resources. One of the most used
16 methods in damage point approach is Ecoindicator99 method that is based on calculating the environmental impacts of the materials and the products (Silvestre et al., 2006a) and (Domingos et al., 2015).
Therefore, LCIA identifies significant issues and evaluates findings to reach more sustainable environmental solutions. The final report, that interprets the results of all the previous methods, is the last element to complete the phases of LCA according to ISO 14040 (Ortiz et al., 2009).
Interpretation:
In this phase, the results are evaluated to assure that they are compatible with the goal and the scope of the life cycle assessment (ISO, 2006b).
This step consists of two basic stages, which are (PE International, 2010): Identification of significant issues that can conclude:
Inventory elements, such as energy consumption, major material flows, wastes and emissions;
Impact category indicators that are of special interest or whose amount is of concern; Essential contributions of life cycle stages to LCI or LCIA results, such as individual unit
processes or groups of processes (e.g., transportation, energy production). Results evaluation.
2.3.3. LCA in construction
Life cycle assessment is an evaluation method developed for designing environmental impact of products. In the construction sector, the final product is a building. However, buildings differentiate from the common products, since they have a long lifespan with lots of changes during all the life cycle processes. Furthermore, buildings are characterised by many different components and materials, making them unique systems. Therefore, performing a full LCA of a building is not a straightforward process like for many other products or materials (Basbagill et al., 2013) and (Lehtinen et al., 2011).
The LCA of a building considers all the processes and all the materials during its entire life cycle. It evaluates energy and resources demand; energy and resources use and the embodied energy and environmental impacts of the construction materials. It also assesses the energy and the environmental impacts are needed/produced to transport these materials from the factory to the construction site (Basbagill et al., 2013).
LCA takes into account the end of life of the components and the entire system whether it will be recycled, demolished or refurbished (Malmqvist et al., 2010). It guides Architects and Engineers into
17 better design decisions especially when it is considered in the early stage of the building life span (Basbagill et al., 2013).
To help seeking more sustainable designs, it is essential to consider that in the construction sector, the operational phase itself contributes more than 50% of greenhouse gases emissions. Furthermore, it is the phase with the highest energy consumption of the total life cycle energy (80 - 85% of the total amount of energy). Thus, an accurate design that searches for more energy and environmental solutions in the operational phase must be considered, in order to achieve a more sustainable building (Sharma et al., 2011).
On the other hand, LCA of a building is not a static process. It varies from building to building, since each one has its own function and different characteristics. For example, construction techniques, architectural style and different conditions such as household size, climate and cultural consumption behaviour vary from country to country. Furthermore, a variation in each design can affect the environment during all life cycle stages of a building (Ortiz et al., 2009).
Although LCA has a very big set of potentialities to help designers in the search of more sustainable built environments, its direct application in the construction sector is not a simple or straightforward process. In fact, it is expensive and cannot be applied without assumptions or additional modifications, facts which could justify why it has not been used so commonly in the construction industry (Norris and Yost, 2001).
Even though, it is possible to find two different kinds of analysis. A first group of studies concerns about constructive solutions and/or materials. A second one regards the LCA of the entire building, quantifying the overall environmental impacts and helping Architects and Engineers in the decision process of finding the most accurate sustainable solution (Ferreira et al., 2015). These studies will be further analysed in chapter 3.
After introducing LCA methodology in the construction sector, the following paragraphs will debate its relation with the concepts and definitions of ISO 14040 and ISO 14044 explained in the previous section.
First, the functional unit (FU) for the construction material and component combinations is focused on a final product. For instance, in a concrete it is 1m3 of concrete; in steel, it is 1kg of steel; in
painting, it is 1m2 of painting, and so on. For the entire building, the FU is normally analysed taking
into account the entire building, a dwelling in case of projects with similar dwellings or, in other specific cases, the m2 of usable floor area (Ortiz et al., 2009).
The life cycle of a building is usually composed of four main stages: (i) Production; (ii) Construction and/or Rebuilding; (iii) Operation and/or Reuse; and finally (iv) Demolition and Disposal. Figure 8 lists the most common aspects to consider in all those four phases.
18 Figure 8 - LCA methodology in construction (Bragança et al 2010)
Finally, the system boundaries of LCA in buildings are explored in Figure 9, which relates all the common life cycle phases of the building with the types of LCA described in the previous section.
Figure 9 – Life cycle assessment stages and types of methods according to the final product (adapted from (Ariyaratne and Moncaster, 2014))
19 2.3.4. LCA tools
Last sections highlighted all the steps and phases needed to perform a LCA study, which are complex and have a large set of data and information that are very difficult to handle without informatics solutions. Therefore, there were developed several LCA tools and software to help experts to perform this methodology (Bribián et al., 2009).
In order to compare and classify the different informatics applications that can be applied to the construction sector, it is possible to classify them in three different levels, which are (Malmqvist et al., 2010):
Basic level – They are simple models with basic input and output covering some environmental impacts that can be performed in normal computation software like MS Excel. Thus, they are very simple to use.
Medium level – LCA calculations are assessed with the help of building software and tools. Examples of these tools are Ecosoft, Legep, Equer, Ecoeffect, and Tally. They need some experience to deal with this software but advanced level of knowledge of LCA are not needed. Advanced level – These are proper LCA software with a general and comprehensive approach.
Examples of these are SimaPro and Gabi. They need a large experience and training and an advanced level of knowledge of LCA is required to handle these software applications on a building level.
On the other hand, to perform LCA in an Architecture and Engineering design context, it is essential to have databases that could help designers to find and study alternative solutions and materials in an expedite way. For that purpose, there have been developed several databases such as Gabi for professional, SimaPro database, Ecoinvent Data, CML, I/O database for Denmark 1999, DEAM TM, The Bousted Model 5.0, BEDEC and US LCI database (Ortiz et al., 2009) and (Bribián et al., 2009). In this thesis, the components of the building and their materials will be analysed using SimaPro as a non-BIM software but as a trust-worthy tool to achieve sustainable building. This software uses EcoInvent and other inventory databases for calculations (Bayer et al. 2010).
In fact, SimaPro is an advanced level software and a science-based tool and it is trusted by industry and academics in more than 80 countries. SimaPro has been the world’s leading LCA software package for 25 years and it is a professional tool that turns its users to leaders of change in the sustainable environment (PRé Consultants, 2017).
2.3.5. Crucial strengths and limitations of LCA in construction sector
Life cycle assessment has several strengths, which have made it spreading and have highlighted its necessity in the construction sector, which are listed as follows (ISO, 2006a), (Wolf et al. 2012), (Antón and Díaz, 2014a) and (Mateus and Bragança, 2012):
20 1. In LCA, many current and serious troubles and issues are discussed ad evaluated earnestly such as: climate change; toxic effects on humans and ecosystems; materials; and land resources depletion. Therefore, LCA allows to predict all the environmental impacts in only one methodology with an easy reporting system that helps Architects and Engineers in the design phase, when comparing different alternatives for a final sustainable construction.
2. LCA assures a wide comprehensive approach of comparison between the products or the systems to choose more preferable alternative product and material and so far, reaching sustainability in the construction industry.
3. LCA is able to identify opportunities to improve the environmental performance of the building for all its entire life cycle or only for certain points in its life, according to the system boundaries, the client needs or even the particularities of a specific project.
4. In LCI, the materials’ quantity and the resources, products and systems are analysed and monitored in the processes. Thus, by interpreting these materials and emissions with their effects, the negative impacts can be modified earlier, in the design phase, throughout changing the material and improve into healthier and more environmental friendly and more profitable solutions. Therefore, LCA can be an important tool to help decision-making towards more sustainable built environment.
5. LCA can give easy indicators which can be used for marketing purposes helping promoters to sell and/or rent and/or operate a building, and users to simply understand the importance of using a green building.
Although LCA is widely recognized as the preferred method to measure the environmental impacts of products, construction solutions and buildings (Mateus and Bragança, 2012), there are still some limitations of this methodology that need further detailed analysis, which can be summarised as follows (Mateus and Bragança, 2012), (Wolf et al. 2012), (Antón and Díaz, 2014b) and (Malmqvist et al., 2010):
1. Further attention is needed in LCA calculations to measure the direct effects of the products on the human health.
2. LCA evaluates regular production processes while accidents are not considered yet.
3. LCA mainly looks at the environmental assessment of the products and the buildings. However, a sustainable construction also needs to have social and economic aspects. While the economic part can be assessed by a life cycle cost (LCC) analysis, which has been also used and developed in several studies, there is a lack of a “social LCA” covering aspects like job creation and equal pay for women, for instance. Consequently, it is needed to develop an integrated methodology considering the three columns of sustainability.
21 4. LCA in the design phase requires numerous solutions and materials. Nevertheless, it is difficult to have all the available data about these materials and products. Moreover, in most of the cases when there is information about them, it is scarce and sometimes not enough to perform a correct LCA.
5. This methodology is very complex, especially in a building context where there are thousands of materials and solutions that need to be assessed. Hence, it is very time-consuming, a fact that normally is incompatible with the exigent deadlines which designers should accomplish.
6. Due to its complexity, LCA needs real experts to be performed in buildings and there is still a lack of these qualified technical people among the design teams.
7. Malmqvist (2010) has mentioned the high costs of implementing LCA in building work as well as results arbitrary, accuracy and problems regarding interpretation of results. Therefore, according to Malmqvist view point, LCA needs to be integrated with other tools that could facilitate its use and reduce its limitations.
These advantages and disadvantages of LCA methodology are inviting Architects, Engineers and experts to integrate and to coordinate LCA with other methodologies such as BIM (Malmqvist et al., 2010). This information can be managed in BIM environment during the entire life cycle of the design, especially since BIM is distinguished by its high level of details (LOD) and very mature level of information (LOI) (BIWG, 2011).
Using BIM environment (tools and interfaces) can facilitate and minimise the obstacles of applying LCA methodology. Due to that, with BIM it is possible to share reliable information about the building. Integrating more environmental information into the 3D BIM model could also help reaching more sustainable buildings, especially when they are analysed in the early stages of the design (Antón et al., 2014b) and (Kylili et al., 2015).
Thus, taking a decision to select better materials and more sustainable strategies will be easier once BIM cooperates with LCA in the early stage of the design, where the building has a variety of potentialities of solutions and alternatives (Malmqvist et al., 2010).
2.4. Building Information Modelling 2.4.1. BIM concept
The maturity of construction industry has been growing and passing throughout many phases from a simple form of building embodiment until reaching recently to a mature methodology of organizing the drawing, models and all the information and stakeholders that are related to the project. This methodology is called Building Information Modelling (BIM) (BIWG, 2011).
BIM methodology enables the building to be represented by intelligent objects that carry detailed physical information and geometrics and understand their relationship with other objects in the building model. BIM dramatically alters all of the key processes involved in the design, such as
22 drawings, visualizations, and how the client’s programmatic requirements are captured and used to develop space, plans and early-stage concepts (Wiley, 2011) and (Liu et al., 2016).
Through BIM concept, design alternatives are analysed for aspects, such as energy, structure, spatial configuration, way-finding, cost, constructability. In the early stage of the design, team members collaborate to determine how the building will be constructed, including the fabrication of different components by sub-contractors; and how, after construction, the building facility is operated and maintained (Azhar et al., 2015). Figure 10 shows the BIM concept and how it can be used throughout the building lifecycle.
Figure 10 - A Visual Representation of BIM Concept (Azhar et al., 2015)
BIM impacts each of these processes by bringing in more intelligence and greater efficiency through improving existing processes and enabling entirely new capabilities, such as (Wiley, 2011):
Checking a multidisciplinary model for conflicts prior to construction; Automatically checking a design for satisfaction of building codes;
Enabling a distributed team to work simultaneously on a project in real time; Constructing a building directly from a model.
BIM can also redefine more mature relationship between the stakeholders and improve the way of thinking of all the coordination parties in the project. BIM-based thinking defines new roles, especially the BIM modeller and coordinator who act as a role to improve the information quality and facilitate better communication (Linderoth, 2010).