BIMaterial Process Design for Material Building Pass

European Architecture, Engineering and Construction industry (AEC) consumes a significant rate of materials like steel, aluminum, copper and plastics, thus creating a large reservoir on secondary raw materials in buildings. One of the main strategies of the European Union is to maximize recycling rates in order to minimize environmental impacts and the energy consumption caused by extraction of primary materials. To enable circularity, and in consequence high recycling rates, information about the existing stock is necessary.

The early design stages play a crucial role in the waste reduction, the reusability of the building elements as well as in the increase of the recycling potential. As planners and architects are major decision makers regarding design, materials, construction and assembly method, they bear large responsibility defining the resources efficiency over the life cycle. In order to optimize the recycling potential and material composition of buildings, new design-centric tools and methods are required as well as tools, which enable a compilation of data repositories on the material composition of buildings. New digital design tools such as BIM enable data management along life-cycle, thus bearing large potentials for generating a Material Passport (MP).

In this project, we developed a concept for the compilation of the MP, as well as a workflow for the semi-automated generation of a MP by coupling BIM to the Material Inventory and Analysis Tool Building One and eco-inventory databases. The proposed methodology allows the assessment of embedded materials in buildings as well as simultaneous LCA. Further on, the MP acts as a crucial instrument for material manufacturers, construction companies, engineers and architects, recycling and waste companies and policy-makers.

The proof of concept demonstrated potentials of the MP as instrument along a building's lifecycle – as design-optimization tool, material-inventory and as a document on material assets of real estates or building stocks, and finally enabling successful implementation of Urban Mining strategies. This project is a central milestone towards standardized, BIM-generated Material Passports.

Starting point/Motivation

Building stocks and infrastructures are the largest material stock of industrial economies. As research findings in Regional Substance Flow Analysis indicate, these total material stocks on the global scale are about as large as primary resource stocks in nature. It is of long-term importance to maintain or frequently recycle these urban stocks, and in consequence to minimize the use of primary resources and thus the dependency on imports. Often, this strategy is labeled "Urban Mining". The increased application of construction materials with some delay triggers the equivalent increase in solid waste generation. Considering the average lifetime for construction products to be 40 to 50 years, a significant increase in solid waste generation is to be expected within the next decades. The only way to respond to the challenge of landfill shortages can be the consequent increase of recycling rates. For higher recycling rates, it is vital to have detailed knowledge about the composition of construction wastes. Recyclability changes over time, as it is a function of technological development and resource markets. Recyclability is also determined through design – it is dependable on constructive criteria defining accessibility and separability of building elements (or its parts). The early design stages play therefore a crucial role in the waste reduction, the re-usability of the building elements as well as in the increase of recycling potential, through the choice of material, construction and assembly method – therefore the planners and architects bear large responsibility. Design-centric methods and tools, allowing planning-optimization and compilation of the deconstruction concepts in the design phase are necessary. New digital tools such as BIM bear large potentials for the documentation and assessment of the material composition of buildings.

Contents and Objectives

The goal of this project is to develop a BIM based Material Passport as knowledge-database serving as design optimization tool; as well as for the compilation of a deconstruction concept in the design stage (design for deconstruction).

The project is aiming is to develop a methodology which would enable a semi-automated generation of a MP through implementation of digital tools. Thereby the feasibility of the MP as suitable tool for optimization of design, as well as for compilation of variant studies and generation of material documentation will be examined. A framework defining requirement specification and parametrics for the compilation of a MP documentation, as well as modelling guideline for planners will be developed. Such a MP is a key means to effective recycling strategies, in particular regarding the complex material composition of modern buildings. Material Passports hence should become a standard procedure for certified buildings, and contribute to the development of a secondary raw materials cadastre, a necessary future completion to the Austrian Mineral Resource Plan.

Methods

In the first step, the scope of necessary information and parameter for MP, as well as the assessment methodology, was defined. Thereby, the data structures and functionality of the MP throughout life cycle stages was determined. In the next step a BIM based workflow was developed. For the generation of the MP and simultaneously the LCA, we propose a workflow by coupling the BIM-model with the material inventory and analysis tool (BuildingOne), where the data from eco-repositories is managed. We are using the data management approach of linking the model with the external eco-databases through BO, instead of integrating the data in the model itself. The data-transfer and analysis of the BIM-model in BuildingOne allows an extensive assessment and analysis of the material composition of a building, such as an assessment of all material-quantities, of percentages of mineralic, metallic or organic materials, of recyclable and waste materials over buildings' life cycle etc.

The proof of concept was compiled on a use case, in order to examine the usability of the proposed analysis and workflow. Finally, a framework was created, which documents the workflow, data structures and modelling requirements.

Results

Within the project BIMaterial a method for a semi-automated generation of a Material Passport was developed. Further on, a concept for parametrization and assessment of a life-cycle-oriented MP was built up. The MP assesses the share of recyclability and waste of a building as well as the LCA. The workflow for a semi-automated generation of the BIM-based MP was defined, which consists of coupling digital tools, such as BIM, an Analysis Tool (BO) and eco-inventories. Further, a framework for software developer, a modelling guideline for the planners and a roadmap for various stakeholder was generated.

The results show that a semi-automated compilation of a MP through coupling of tools and integration of building catalogues is possible.

Prospects / Suggestions for future research

The conducted research has shown that the developed method, which is based on coupling various digital tools, is appropriate for the compilation of a semi-automated MP. Within the project we focused on the conceptual and the planning stage, where the MP serves as a decision support- and optimization tool for planners. In a further step, the development of a plug-in as a software product for an automated generation of the MP should be approached.

The proof of concept for the generation of the BIM-based MP has demonstrated the potentials for modelling and predicting material flows on urban-level. Coupling of BIM and GIS would make predictive modelling on urban-level possible with one condition: the existence of data about the material composition of buildings. Therefore, new digital methods for capturing of material and geometry, as well as algorithms for a semi-automated generation of the BIM models, have to be tested and developed. In a further step, the created material documentations can be integrated in GIS in order to serve as a secondary raw materials cadaster.