Digital Twin Footprint - Erarbeitung eines ganzheitlichen Meilensteinplans mit Handlungsempfehlungen und notwendigen Forschungsbausteinen zur zielführenden Verknüpfung der Lebenszyklusanalyse (Gebäudeökobilanzierung) und BIM-Planungsprozesse mit einem Fokus auf den frühen Planungsphasen
Dokumenttyp:
Report / Forschungsbericht
Autor(en):
Bahlau, S.; Schumacher, R.; Lambertz, M.; Theißen, S.; Höper, J.; Borrmann, A.; Forth, K.; von Both, P.; Ebertshäuser, S.; Horn, R.
Abstract:
Climate neutrality and digitalisation – megatrends that are currently very popular and present the construction industry with new challenges. With a tightening of the EU's climate targets by 2030, the aim is to reduce greenhouse gas emissions by 55 % compared to 1990. The construction and building sector, being the largest greenhouse gas emitter, owns a key role here (Global Alliance for Buildings and Construction 2020). The continuous digital linking of the diferent process chains in the building planning process is able to decisively reduce environmental impact of the construction industry and lead to a sustainable and resource-saving transformation of the built environment. The Digital Twin Footprint research project is developing a milestone plan with recommendations for action and research modules to link life cycle analysis (building life cycle assessment) and the BIM planning process (BIM – Building Information Modelling) in the early planning phases of buildings. While in theory the construction and building sector is said to have a high potential for optimisation in terms of climate and environmental impact, in practice there is still a lack of holistic measures and specifcations. There are many reasons for this. Among other things, the focus often is only on purely energy-related measures, as previous political measures in the building sector have mainly addressed the increase of energy efciency and the use of renewable energies. By focussing on energy savings and the resulting emissions in the operating phase, the environmental impacts over the entire life cycle of a building are not recorded, although there is great potential for optimisation here. Material-bound CO2 emissions, often referred to as embodied carbon, can account for up to 80 % of the total, especially in the case of high energy efciency standards (RICS 2017). In order to be able to present and evaluate climate neutrality transparently and consistently, it is therefore necessary to carry out a complete calculation of CO2 emissions and other environmental impacts over the entire life cycle. According to the defnition of the German Sustainable Building Council (DGNB), buildings are defned as climate-neutral "if the diference between the emissions emitted and the emissions saved through production and provision of external CO2-free energy is zero or less than zero over a period of one year" (Deutsche Gesellschaft für Nachhaltiges Bauen – DGNB e.V. 2022). Novel and innovative approaches with an open data exchange strategy (Open-BIM) ofer a great added value to simplify the assessment with regard to the CO2 balance and make it applicable in practice. One of the most important methods in the feld of sustainable construction or to achieve climate neutrality is the Life Cycle Assessment (LCA). This method makes it possible to achieve CO2 and other environmental and resource-related optimisations over the entire life cycle, especially if the LCA is already used in the early planning phases. In building practice, however, this method has so far been used only rarely or only in sustainability certifcation systems for buildings. In these cases, the ecological balance is usually carried out too late, after the planning has been approved, which means that ecological optimisation potential can usually no longer be used. In addition, the technical building equipment is usually only taken into account in a generalised way and is underestimated (Lambertz et al. 2019). The main reason for this is the complexity of the application, as the necessary information and data procurement from the many project participants and databases is unstructured and mainly based on 2D planning documents (Gantner/Both et al. 2018).Thus, additional eforts for holistic, ecological building planning and renovation concepts are avoided, not least because of the supposedly too high complexity and costs. However, the BIM method in general and with regard to open data exchange formats, such as the Industry Foundation Classes (IFC), ofers great potential for carrying out life cycle assessments of buildings much more efciently and comprehensively (Theißen/Höper/Wimmer/Zibell et al. 2020). Due to the uniform structuring of the information required for the calculations and its easier accessibility within the BIM models, there is a high automation potential for carrying out a life cycle assessment of a building. The basis for this is a simple and standardised linking of the LCA data with BIM objects in the planning process (Höper 2020). Although there is already initial research and development in this area, the fndings have not yet been brought together or placed in a coordinated context. Many approaches are not directly practical and only work in their own software and research project environment. Although the frst LCA software products on the market enable a BIM-based calculation of the building life cycle assessment, they mainly only work with manufacturer-specifc data formats (closed BIM approach). The aim should be to implement BIM-integrated life cycle assessments in the open BIM approach with open and standardised data exchange formats. In this way, vendor neutrality and a diversity of the modelling and planning software systems used can be maintained depending on the discipline (Theißen/Höper/Drzymalla et al. 2020). Therefore, there is a great need to compile previous solution approaches from research but also from current practice in the BIM&LCA feld, to classify them with regard to their applicability and to evaluate and discuss advantages and disadvantages. The overall objective is to establish a high level of interoperability between BIM planning software solutions and the (ecological) specifc LCA data in the diferent planning phases. In this way, partially automated LCA calculations and optimisations can be carried out at an early stage and, at the same time, time-consuming and cost-intensive changes can be avoided in the later planning phases. Thus, within the framework of the Digital Twin Footprint project, it is important to analyse and compare previous principles, concepts and solutions in the area of BIM and LCA of buildings in order to create a common understanding and a coordinated, harmonised solution for a future, broad application of BIM-based LCA of buildings. This aspect is also relevant to avoid duplication of research and to create a harmony of research, practice and standardisation. In an expert workshop (AP2), the necessary adaptation and research requirements for diferent applications were concretised and prioritised in discourse with the experts. The findings were discussed and coordinated with various relevant viewpoints and perspectives, e.g. public institutions, BIM software representatives, LCA experts, etc., in order to prepare milestone planning and recommendations for action (AP3). In addition, the research potentials and topics for future and target-oriented proposal and contract research were identifed. To further break down the recommendations for action or adaptation needs, measures were formulated in AP3 that are necessary for a practical application of LCA with BIM. This was followed by identifcation of the levels of action or actors for whom it is proposed to implement the measures. With a classifcation in a timeline (short, medium, long term) and the efort, the relevance and feasibility of the measure should be highlighted. This will make it possible to support a future federal research strategy and practical application that promotes the iterative and planning-accompanying use of building life cycle assessment in order to be able to optimise buildings along the life cycle in terms of climate and environmental protection.
Stichworte:
LOCenter; BIM4LCA;
Beauftragende Einrichtung:
Bundesinstitut für Bau-, Stadt- und Raumforschung (BBSR)