As earlier mentioned, material passports allow better understanding and accounting of the different elements out of which a building consists of. This, in turn, allows the proper and efficient utilisation of the elements and materials in other construction projects.
Perhaps one of the leading qualities of material passports is the fact that the concept can be applied for both new projects as well as already existing buildings.
8.1 Case study: New office building, Germany
The following case study allows insight into the utilisation of material passport as well as its challenges and possibilities. The building in question is located in Essen, Germany, directly in the middle of a UNESCO world heritage site of a previous Zollverein Coal Mine Industrial Complex, the “Zeche Zollverein” (BAMB, 2016). The building was designed by Kadawittfeldarchitektur architectural office and was built between the years 2016 and 2018 (Kadawittfeldarchitektur, 2019).
The total gross floor area is approximately 9.400 m2 and facilitates the offices of RAG Foundation, the largest coal mining company in Germany (Kadawittfeldarchitektur, 2019). Also interestingly, perhaps because the building is located directly next to a large forest, the architects designed its roof to form a large communal garden. The garden is accessible to all public and consists out of small sand paths between the flower and vegetable banks. The building is built in a unique way in a large L-shape form. Since the Zollverein UNESCO site attracts over 1,5 million tourists yearly, the L-shaped building also serves as a viewpoint over the protected industrial and natural landscapes surrounding the building. (BAMB, 2016)
The structure is an example of innovative sustainable construction and, as the previously discussed Tegel Airport, has received the highest DGNB certification, platinum (Kadawittfeldarchitektur, 2019). The building was a pilot project of Buildings as Material Banks (BAMB) aiming to introduce the usage of material passports into the construction industry. BAMB is a project between 15 partners from seven European countries that aims in creating circular solutions for the construction industry and thus inducing a systemic change for a greener future. The project started in September 2015 as a research project funded by the EU. Its goal is to increase and sustain the values of the materials used for buildings through design and circular value chains.
This causes a positive impact on the waste produced by buildings and by allowing better recycling of materials it minimises the consumption of virgin materials. In other words, by using buildings as banks of valuable materials, BAMB´s goal is to decrease the extraction of natural resources to a level that our planet can withstand. (European Energy Innovation, 2017)
In order to achieve the highest level of circularity and allow maximal usage of the materials later in the building´s life, all the materials and components used are selected for their recyclability. This will enable the building´s materials to sustain their value and qualities even when the building itself reaches the end of its lifespan (Kadawittfeldarchitektur, 2019).
The tool
In order to reach their sustainability goals, BAMB has designed an electronic tool that enables detailed collection and storage of the materials present in a building. The tool categorises the materials according to their life span, quality, recyclability and adaptability during the planning, construction and modification process as well as during the main life cycle of the building (Figure 29). It provides information that allows more straightforward modifications and adjustments to different purposes. It also creates a more sustainable demolition process which produces more reusable material and less landfill waste. (BAMB, 2016)
Fig. 29: Screenshot of the BAMB online tool. (BAMB, 2016)
Figure 29 above illustrates a screenshot of the online tool created by (BAMB, 2016). It allows critical information and data to be easily observed and accessed in a single view.
The following Figure 30 illustrates the possible differences in detail and target for different material passports as they can be created either for singular products or for larger components such as whole buildings.
Fig. 30: Material Passports compared to the Building's Materials Passport. (Mulhall, et al., 2019; based on Brenner, 2010)
Figure 30 presents the various possibilities for the utilisation of material passports.
They can contain either smaller amounts of information, for example concerning a single product or element (shown in the smaller, orange circle in the figure), or they can be implied on a larger scale such as a whole building (presented in a large green circle in the figure). In the latter version, the material passports are referred to as Building´s Materials Passport (BMP). In this case, the total information included in the passport is obviously also a great deal broader and contains a substantial amount of data varying from the chemical substances used in materials all the way to building components and functional units used in the construction process.
Since the amount of information included in a BMP is so vast, the project leaders in BAMB decided to create an online electronic tool to make the data easier to handle without increasing the amount invested in the planning and design process. The final BMP online tool which was created and used for the pilot project of the office building included the following aspects:
1. The material health
2. The recyclability and repairability of the components 3. The transformation and reuse potential of the components 4. Life cycle assessment (LCA) of the materials
5. Resource value potential. (BAMB, 2016)
According to the report released by BAMB in 2016, the material passport combined with the recyclable design would allow the project to save up to 4.641 tonnes of construction waste from ending up at landfill sites, 91 tonnes of waste does not need to be thermally treated and up to 12.108 tonnes of material can be recycled without value loss or alteration of quality. The following figure shows the summary page of the BAMB tool created for the office building project.
Fig. 31: The Zollverein Project’s overview page on a material passport. (BAMB, 2016)
As seen in Figure 31, the online tool used for material passports can be created in a user-friendly way where all of the main details and information on the product or building can be observed in one simplified view. This summary page includes data from the main five aspects mentioned above: LCA, material health classification, dismantling potential, recyclability of the materials and separability of the components. In addition, it also shows the necessary information about the project, along with the current planning phase.
The pilot project along with the implementation of the material passport was seen as a success, and it was considered to present a realistic model on the application of the research project BAMB to an actual market environment. Due to the fact that is was also able to offer hard data as evidence, it was evaluated fitting for the strict economic requirements of today´s construction industry. This, on the other hand, was hoped to increase the probability of other construction companies taking advantage of material passports in their own projects and beginning to perceive buildings as valuable material sources.
8.2 Findings
The main advantage of material passports is that the concept can and should be combined with almost all other circular methods. For example, in order to build a house using recycled materials and components, one must first plan and gather information about those materials and where they can be harvested from. Furthermore, as already briefly mentioned, material passports can be implemented in both already existing buildings as well as in new ones during their design process. The passports also add to the total value of the building by allowing better preservation of the value of its materials, thus allowing a positive cash flow at the end of the building´s life.
Since material passports are so versatile, they can be applied and adapted at any point of the building life cycle. They can be created already during the design and planning process, updated during possible renovations or they can be created later on for buildings that have already been build centuries ago.