Life-Cycle Assessment as a decision-support tool for early phases of urban planning: evaluating applicability through a comparative approach

While ambitious environmental objectives are being set for new constructions in Switzerland, the assessment of urban-scale projects and comparison of their performance to national targets are made possible by a growing number of life-cycle assessment (LCA) tools. However, previous research emphasizes the lack of existing tools to support the decision-making process at the early design stage, characterized by a low level of project details. This paper presents a comparison between three LCA tools. The first, stemming from a research and development project (SETUP), is an exploration tool relying on a database of urban-level scenarios and their environmental performance, able to convert district targets (e.g. 2000-Watt society objectives) into specific sub-targets at the building or component levels. The other two are online LCA tools currently available to practitioners (Sméo and Calculation tool for 2000-Watt-society-sites RH II ), that allow assessing the project and verifying its compliance with a given target. Each tool was applied to a low-carbon case study, the blueFactory district in Fribourg (Switzerland), in two hypothetical contexts corresponding to the schematic and detailed project development phases, characterized by different levels of details. When used for the assessment of a project at a more advanced development stage with a high resolution of detail, findings indicate that Smeo and RH II provide similar environmental performance results. However, in early planning stages, SETUP shows better abilities to support decision-making by providing ranges of results and highlighting uncertainties and the influence of design parameters that have not yet been fixed.

Setting contextual life-cycle objectives in urban design: requirements for a decision-support method

Marilyne Andersen, Thomas Bernard Paul Jusselme, Émilie Nault

A variety of building labels and norms exist that set evermore-ambitious environmental and energy performance targets. In parallel, a growing number of building performance evaluation tools are adopting the life-cycle assessment (LCA) methodology to allow verifying if a project, based on its detailed description, reaches these targets. However, such norms and tools seem unsuited to the district scale, where environmental impact considerations are often left out of the urban planning and design process. There specifically appears to be a lack of decision-support instruments that can relate urban-scale performance targets to concrete design choices, taking into consideration the project’s specificities (e.g., climatic context), but without requesting design information that is not yet available. This paper presents the first phase of a collaborative research and development project, aiming at developing a novel decision-support method to integrate life-cycle objectives from the masterplanning stage. In this first phase, we investigate barriers and requirements from a practice-oriented perspective in the Swiss context by: (i) exploring urban-scale LCA-based methods and tools, and (ii) engaging with key stakeholders who hold complementary roles in a case study district project, which aims to be low-carbon. These exchanges are conducted in the form of a focus group and a questionnaire to gather qualitative and detailed information. Our findings notably highlight the mismatch between the ambitious objectives set by regulations and labels and the (lack of) means available to practitioners to support them in achieving these objectives. Specifications for a novel tool are derived from the practitioner’s feedback, as well as information on relevant design parameters and performance indicators.

2018

Specific Environmentally-conscious Targets for Urban Planning – A method to inform the decision-making process

Émilie Nault

Ce projet collaboratif entre chercheurs académiques et partenaires industriels vise le développement d’une méthode d’aide à la décision dans la planification urbaine. Appliquée sur le projet de quartier blueFactory à Fribourg, et mise en œuvre sous forme de prototype d’outil interactif, cette méthode permet de décliner des objectifs environnementaux fixés à l’échelle du quartier (ex. cibles de la société à 2000 watts) en cibles spécifiques et différenciées par niveaux sous-jacents (ex. bâtiments, composants). L’approche repose sur une base de données de scénarios de bâtiments pré-simulés spécifiques au site, générés en variant divers paramètres tel la forme du bâtiment et les matériaux de construction. Des indicateurs environnementaux ainsi que les coûts de construction sont évalués pour chaque scénario. En interagissant avec la base de données, les décideurs peuvent anticiper dès la phase de masterplanning l’influence et le poids des différents paramètres pour chaque indicateur. Les choix de design pouvant compromettre la faisabilité du projet à atteindre les objectifs ou restreindre la liberté dans les décisions à venir peuvent également être identifiés. This collaborative project between academic researchers and industrial partners aims at developing a method to provide decision support in urban planning. Applied to the blueFactory district project in Fribourg, and implemented as an interactive prototype tool, this method allows converting a performance objective set at the site level (e.g., 2000W society target) into specific and differentiated targets at sublevels (e.g., buildings, components). At the core of our approach is a pre-simulated database of project-specific building scenarios, generated by varying multiple parameters such as building shape and construction materials. Environmental indicators as well as construction costs are evaluated for each scenario. By interacting with the database, practitioners can anticipate from the masterplanning stage the influence and weight of the different parameters for each indicator. Design choices that may compromise the project’s feasibility of achieving the objectives or constrain the freedom for downstream decisions can also be identified.

2018

Conception et évaluation d'un prototype de simulation de la morphogenèse urbaine par agents vecteurs multi-échelles

Vitor Silva

The research work of this PhD thesis was carried out in the context of an interdisciplinary project related to the study of urban morphogenesis. A team composed of architects and engineers specialized in GIS technologies have worked together in this project during three years, sharing their knowledge in order to understand and simulate the evolution of the urban environment of cities. The fundamental hypothesis that conducted this research is that the city can be seen as a self-organizing system governed by a set of morphogenesis rules, which can for example, determine the location of new architectural programs and induce the city's organization, from local to global scales. Architectural programs themselves are supposed to determine city's development. In this PhD thesis a simulation prototype of the urban growth based on the use of multi-agents systems was carried out. This prototype is a computer tool that allows the analysis and representation of the growth of the built environment. Nowadays, the ability to understand and simulate urban evolution proves to be essential in order to control the evolution of a city in a sustainable development view. Furthermore, this tool should facilitate the understanding and decision-making of those concerned with problems related to urban development. The urban system has been modeled as a set of space objects, such as buildings and networks, which interact between themselves. These interactions are carried out at different levels, from local to global scales, being controlled by behavioral rules or laws of growth. The result of their interaction can be figures or emergent phenomena represented at several scales. The approach using multi-agents vector systems was chosen in order to model a geographical complex system like a city, which integrates a vectorial modeling of space. Hence, each spatial agent does not possess a limit of form and size. The interest of using multi-agents vector systems also lies in their ability to manage various models of individuals, from simple entities to more complex ones. Thus, various levels of representation, such as individuals and groups of individuals, can be managed, which is not easily feasible, for example, with cellular agents. The development platform used is GeOxygene (Java computer programming language), which is an open-source platform developed at IGN (Institut Géographique National, France), by COGIT laboratory. This platform provides several GIS functions, allowing the development and implementation of the prototype here presented. An interaction model between agents was defined and the type of scenarios of each of these interactions was detailed. A set of methods and associated classes was developed. Agent's architecture was conceived in order to allow manipulation (sending, receiving and treatment) of exchanged messages. In order to show the relevance of the multi-agent multi-scale methodology, examples of buildings creation in a case study zone were carried out. Using the multi-scale vector simulation prototype here presented, the development of cities can be computed in a very innovative way. However, the developed prototype still lacks some accuracy, mostly due to the fact that the specified laws adopted for simulation do not reflect the whole reality, which is obviously much more complex to traduce. We have not yet validated the model for other cities – nevertheless, the model could already be used as a decision support tool, particularly as a planning support instrument for architects and urban planners. With regards to future work this prototype shall be integrated in a global approach of urban simulation, allowing the analysis of environmental risks, demographic and economic growth and transports simulation at different scales of analysis and 2D/3D visualization output, such as district and city.

EPFL2010

Conception et évaluation d'un prototype de simulation de la morphogenèse urbaine par agents vecteurs multi-échelles

Vitor Silva

EPFL2010

Specific Environmentally-conscious Targets for Urban Planning – A method to inform the decision-making process

Émilie Nault

2018