The use of digitized EPDs
Article by Monica Lavagna, Politecnico di Milano, Department of Architecture, Construction Engineering and Built Environment (Dabc)
The application of LCA (Life cycle assessment) assessments, during the various phases of the building process and, in particular, in the decision-making phase of the project, is emerging due to the presence of rewarding criteria present in the sustainability assessment protocols of buildings, such as Leed and Levels, but also in Public Procurement (CAM).
EPDs (Environmental Product Declaration) constitute a very important source of specific product data to support the performance of an LCA assessment of a building or infrastructure, but data management (both as collection and as manipulability) is a particularly critical and time-consuming aspect. -consuming for end users (in particular designers).
The ability to digitize the information contained in the EPDs (so far managed on static pdf files, to be copied and pasted to be made available within calculation tools) and in particular to be able to import data into calculation software for LCA evaluation and in the BIM environment, it is an element of great facilitation.
For this reason, international efforts have been made to offer “machine-readable EPDs”, transferring some of the information from an EPD in a machine-readable format (XML file). The information drawn from the EPD consists of LCA data and metadata and is stored in a structured way that facilitates the use of the information in other applications. The structure and format of the data are aligned with what is defined by the International Open Data Network for Sustainable Building (InData) working group.
A very flexible format
The InData initiative builds on existing tools and standards and uses the ILCD + EPD data format developed by the European Commission’s DG JRC. The format chosen offers high flexibility, which allows adaptation to specific national requirements (e.g. recycled content required by CAM in Italy) or future changes based on the evolution of standards (e.g. amendments to the EN 15804 standard).
Currently in BIM there are libraries of materials (generic) associated with the generic properties of materials, and in some cases environmental values already exist (for example in Archicad from the ICE database, Inventory of Carbon and Energy). However, when you go to the executive phase, you define specific products and therefore draw on objects that identify the products, with their specific technical performances. Importing digitized EPDs into BIM could therefore be particularly useful.
To date, however, the import of data into Revit / Archicad is not automatic, but it is necessary to process the data from the XML file using Dynamo / Grashhopper. Furthermore, there is still no possibility of automatically associating XML files with BIM objects, so it is necessary to “manually” associate each individual EPD to the individual product. The environmental information of the EPD thus loaded remains static information, which cannot be automatically processed in BIM. The processing of environmental data is possible by creating specific calculation algorithms.
A particularly delicate aspect in the import is also the definition of how to correlate the functional unit of the EPD (kg, m2, m3, piece, etc.), with the associated product / object in BIM (which is expressed in a predefined quantity ). The data import must be done by correlating it to the quantities of the object with a formula to be written ad hoc in the respective algorithmic writing plug-ins.
The digitization of EPDs is only an important first step towards the effective integration of data in BIM and in LCA calculation software. The LCA applications developed for the Revit software (such as LCA One-click and Tally) are also closed systems, therefore they do not allow you to upload XML files.
Further work is underway on the standardization of the data structure: precisely to guarantee data exchanges in the BIM environment, ISO / CD 22057 Enabling use of Environmental Product Declarations (EPD) at construction works level using building information modelling (BIM) is being defined.