METHODOLOGICAL DISCUSSION AND PILOTING OF LCA-BASED ENVIRONMENTAL INDICATORS FOR PRODUCT STAGE ASSESSMENT OF BRAZILIAN BUILDINGS

The International Energy Agency (IEA)’s Annex 57 was established to advance on evaluation of embodied energy and GHG emissions for building construction. Its activities include recommendation of common calculation methods and disclosure of regional benchmarks. Process-based, input-output or hybrid life cycle assessment (LCA) can support such calculations. Identification of the major products that describe key building typologies plays a strategic role in the tasks of streamlining indicators’ monitoring scope and LCI data gathering in contexts with little LCA practice consolidation. Given these motivations and backdrops, our main goals are (i) to calculate a selected set of LCA-based indicators to synthetically describe environmental performance of construction products for three functionally equivalent case studies; (ii) to detect the major contributors to embodied energy (EE) and emissions (EGWP); and (iii) to examine the implications of considering embodied CO2 versus total GHG emissions. The selected metrics include – besides EE and EGWP targeted by Annex 57 – the blue water footprint (bWF), non-renewable primary material consumption (NRc) and volatile organic compounds (VOC) emissions. Production cycle modeling used previously collected national data, as well as secondary data extracted from national and international literature or adapted from international databases whenever considered as reasonably similar to Brazilian processes. EE and EGWP results were calculated using the Cumulative Energy Demand (CED) method and the CML 2001 baseline v. 2.05 method, respectively, and are presented for the top contributing products. NRc, bWF and VOC calculations were directly derived from the inventories and discussed in more detail for cement and concrete. Around 80% of the total embodied energy was related to seven construction products, while four of them also responded for around 80% of embodied GWP. Enlarging the database to encompass ten core products would increase coverage to over 93%. For cement and concrete, partial replacement of clinker by ground granulated blast furnace slag brought substantial reductions in the calculated values for all indicators but bWF, which unveils the effect of the water-intensive granulation process. Further research is expected to advance in LCI development and validation to enable the use of life cycle-based metrics to support decision-making within the national building sector

Impact distribution methods’ use in multifunctional Life Cycle Assessments: a systematic literature review

Partitioning loads related to multifunctional processes, which generate more than one product or service (i.e. function), is a controversial issue within life cycle assessment (LCA). ISO 14044:2006 suggests a hierarchic stepwise procedure. The first step is to avoid allocation whenever possible, through (i) subdividing the multifunctional process into unitary sub-processes with one specific function; or (ii) expanding the system boundaries to include the additional functions related to by-product(s). The second step determines that the system’s inputs and outputs must be allocated based on a fundamental physical relationship between products. When one is unable to identify such physical relationship, flows must be partitioned as to reflect other relations between products, such as their economic value. This paper aims to delineate a scientific overview of the impact distribution methods’ use within LCA practice from 2006 to 2016. Authors performed a systematic literature review and documented methods’ choice frequency within studies published in the considered time frame. Results revealed a lack of consensus among LCA practitioners. Most papers adopt the avoided burden approach (equivalent to system expansion), while the first step proposed in ISO 14044’s hierarchy (subdivision) was actually the least used method. Our examination confirmed that the impact division problem is typically solved by substantially diverging from ISO’s theoretical framework, which suggests both an opportunity for reflection and a reformulation need

Embodied GHG emissions of buildings – The hidden challenge for effective climate change mitigation

ISSN:0306-2619ISSN:1872-911

Appropriateness of environmental impact distribution methods to model blast furnace slag recycling in cement making

Environmental impact allocation has been noted as one of the life cycle assessment's (LCA) most controversial methodological issues given that it highly influences the study's final result. This paper analyses the appropriateness of available multifunctional modeling methods to distribute environmental loads between pig iron and bfs produced in the steelmaking process, and the influence that modeling choices have on LCA results for different blended cement types commercialized in Brazil. Allocation by mass and by economic value, as well as system expansion, are examined for ordinary Portland cement and two types of blended cements with higher ggbfs contents as clinker replacement. The support platform used for performing the LCA was SimaPro 7.3, and the impact evaluation method was CML 2001 (baseline). The data for the production processes' modeling came from national and/or local reports; when national data were unavailable, the corresponding processes found in the SimaPro built-in Ecoinvent database were adapted to better represent the Brazilian context. As expected, impact allocation based on mass induces large impacts on bfs and the environmental loads of blended cements gradually increase with the increased bfs content. A similar trend was observed for economic allocation, except for global warming and terrestrial ecotoxicity, which are particularly sensitive to the allocation procedure choice. In the system expansion approach, impact values in all categories decreased with increased ggbfs content in cement. Impact distribution across products is a legitimate way for an industry to be held accountable only for the true impacts of a given process. Each method presents its advantages and disadvantages. Independently of the criterion chosen, the conceptual limitations of allocation methods are that they do not look beyond impacts partitioning, and awkward ratios between physical characteristics and market value blur the vision and distort results. In our case, the system expansion approach precisely modeled the studied processes, following a complete and conceptually consistent description, which also allows for consideration of potential improvements at whole-system level99404

Impact allocation in the steelmaking industry and its influence o cement's life cycle assessment results

Orientador: Vanessa Gomes da SilvaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e UrbanismoResumo: O setor siderúrgico brasileiro, já há algum tempo, focaliza esforços na minimização das cargas ambientais do processo produtivo do aço. Devido à grande quantidade de co-produtos gerados no processo, o setor prioriza a disseminação de ações relacionadas com a reciclagem das escórias siderúrgicas, e encontra na indústria da construção civil um importante mercado consumidor. A reciclagem das escórias em componentes e materiais de construção é promovida como ambientalmente benéfica para ambos os setores, uma vez que a escória siderúrgica substituiria um material natural não renovável ao mesmo tempo em que reduziria a demanda energética da indústria siderúrgica. Tais fatos têm sido sustentados pelo entendimento de que as escórias são uma consequência, e não o propósito final do processo de produção do aço; este último recebe, portanto, toda a carga ambiental correspondente. A busca pela justa distribuição de impactos entre um produto e seus co-produtos ganhou impulso nos últimos anos. Nessa ótica, a Avaliação de Ciclo de Vida (ACV) possibilita a atribuição de impactos ambientais entre produtos e co-produtos, com base em diferentes critérios. Visando à compreensão da influência do critério de alocação de impactos sobre os resultados da ACV para o processo siderúrgico e sobre o emprego de escória de alto-forno como matéria prima no setor de construção, a presente dissertação de mestrado objetiva a realização de ACVs (aço; escória de alto-forno; e três tipos de cimento Portland, com diferentes porcentagens de adição de escória de alto-forno) para análise comparativa dos resultados decorrentes do uso de diferentes critérios de alocação de impactos (com base na massa e no valor econômico do aço e da escória de alto-forno) e da expansão das fronteiras do sistema. Para o tratamento e a interpretação dos resultados foi utilizada a plataforma de apoio SimaPro 7.3 e a avaliação dos impactos foi realizada por meio do CML 2001 (baseline). Os resultados demonstraram a relevância da discussão quanto ao critério diretor de distribuição de impactos, que, nas condições estudadas, tiveram um reflexo importante na carga ambiental transferida para os cimentos que utilizam a escória de alto-forno como matéria-prima alternativa. Dando continuidade à pesquisa, pretende-se expandir o escopo para englobar outros aspectos metodológicos de interesse na Avaliação do Ciclo de Vida, considerando as etapas que enfrentam os maiores desafios de realização no Brasil, limitando o seu potencial de aplicaçãoAbstract: Brazilian steelmaking sector has, for a while now, struggled to minimize the environmental loads of the steelmaking process. Because of the great amount of co-products generated in the process, the sector prioritizes dissemination of actions related to steel slag recycling, and relies on the construction industry as an important consumer market. Slag's recycling in construction materials and components is promoted as environmentally beneficial for both sectors, considering that the steel slag would replace a non-renewable natural material, while reducing the steel industry's energy demand. Those facts have been sustained by the understanding that steel slags are a consequence, and not the final purpose of the steelmaking process; steel, therefore, receives the entire corresponding environmental load. The search for fair impact distribution between a product and its co-products has gained a boost in the last few years. In that perspective, Life Cycle Assessment (LCA) allows for an impact assigning between products and co-products, based on different criteria. Aiming at a better understanding of impact allocation criteria's influence on steelmaking LCA results and on blast furnace slag use as a raw material in the construction sector, this thesis aims at performing LCAs (steel; blast furnace slag; and three types of Portland cement, with different percentages of blast furnace slag addition) to comparatively evaluate results deriving from the use of different impact allocation criteria (based on the mass and economic value of steel and blast furnace slag) and from system boundaries expansion. For results treatment and interpretation, SimaPro 7.3 was used, and impact evaluation was performed through CML 2001 (baseline). Results confirmed the relevance of the discussion regarding impact distributions' defining criteria, which, in the studied scenery, had a very important reflex in the environmental load transferred to cements that utilize blast furnace slag as an alternative raw material. Further researches are expected to expand the scope to encompass other methodological aspects within LCA, considering the stages that face the greater challenges in Brazil, limiting its application potentialMestradoArquitetura e ConstruçãoMestre em Engenharia Civi