The Building Circularity, Greater London Authority (GLA) tool allows tracking, quantifying and optimizing the circularity of materials sourced and used during the building life-cycle, as well as the circularity at the end of life. It allows getting a holistic picture, as well as a detailed breakdown per material type. It also supports applying Design for Disassembly and Design for Adaptability principles. This tool has been created to return results according to the Greater London Authority's circularity requirements and can be used alongside the GLA LCA tool as well as for other circular design purposes.
The goal of the Building Circularity tool is to calculate the circularity percentage of your building / asset. It does not have a mandatory scope and can be used to access single materials or whole buildings.
To set up the Building Circularity, GLA tool, you will first be prompted to set up your LCC parameters. Select the country that your project is taking place in, and click “Load regional cost parameters”. For the cost calculation method, select “Always input costs myself”. The other options require an LCC license. You can then change any of the following fields if necessary. When finished, click save.
In order to understand how our new Building Circularity, GLA tool works we will explain the important parts of the tool, including the building material query, the circularity score weighting factors, the calculation period, the building area and the results page.
The building material query is the section of the tool in which you will have to enter data about your materials, the circularity score weighting factors lets you adjust your weighting factors, the calculation period is where you can enter the service life of the building, the building area is where you put in the gross floor area of your building and the results page will help you visualize and understand your circularity results.
Building material query explained
You will first have to enter some data. You can do this either directly by adding materials in the building material query of the Building Circularity, GLA tool or by adding the tool to an existing design with data. Once you have added several rows of data, it will look like the screenshot below. For users of other LCA tools, you might notice that there are a few new sections in the Building Circularity, GLA tool.
Recycled, Renewable or Reused contents
The first section that is important is the percentage of recycled, renewable or reused materials in the resource. If you know that a certain material actually consists of recycled, renewable or reused materials, you can edit these percentages accordingly.
With the recycled, renewable or reused percentage, tis number means the share of either recycled, renewable or reused materials in the product by mass. This information does not influence the LCA results but is used to document material circularity. Some products have the recycled, renewable or reused percentage defined with a default value, which can be based either on the product or the type of product.
Wastage defines the construction site wastage for the material. Defaults are set based on typical wastage and will vary based on the construction process, building and design.
Design for Disassembly and Design for Adaptability
With DfD you should check if the material installation considers Design for Disassembly practices, e.g. using dismountable fasteners instead of glue or if it allows otherwise non-destructive removal of the material.
With DfA you should check if the material is adaptable for future adaptions of the use of the building.
End of Life processes
By default, materials will have been assigned an end of life process. These processes are based on the material type, and you will notice that there will be differences in the end of life processes depending on what material options you use.
If you click on the end of life process, you will see that you are able to select different end of life processes. Select here what is appropriate for your project.
Circularity score weighting factors
In this section, you can adjust the weighting factors for your materials recovered and materials returned if desired. Default values are already set here, but you are able to change them if you would like by typing them into the corresponding text box then clicking save in the top right corner.
In this section, you will add a calculation period for your building so the calculations can be reflected based on the service life of the building. Type the service life of your building in the text box and then click save in the top right corner.
The building area query is where you set the area of your building so this can be used for results calculations. You can use the drop down menu to select the Gross Internal Floor Area and then enter the corresponding amount in the field and click save in the top right corner.
How to interpret the results
The Building Circularity graph explained
The percentage of materials recovered (in this case, 4.1%) is formed as follows:
- Virgin material recovered - Score not included
- Renewable material recovered - Full score included
- Recycled material recovered - Full score included
- Reused material recovered - Full score included
The percentage of materials returned (in this case 51.4%) is formed as follows:
- Materials used as materials. Full score included
- Materials recycled - Full score included
- Materials down-cycled - 50% of the score included
- Materials used as energy - 50% of the score included
- Materials disposed of - Score not included
The Building Circularity score, (in this case the 28%) which is shown in the middle, is the average from the materials recovered added up to the materials returned.
Building Circularity - Bill of Materials
In this section, you can see the bill of materials for your circularity assessment split by result category. Various breakdowns are available, including the total material quantity’s weight, as well as the intensity of the material and recycled and reused content by value which relates back to the LCC parameters.
Building Circularity - Materials recovered
In this section of the results page you will be able to see your recovered materials, and how much of these materials are either virgin materials, materials that are renewable, recycled or reused materials. The amounts represented here come from the percentages that are given to each section in the building material query. If you press the 'details' section, you will be able to see e.g. exactly which construction materials contribute to the virgin, renewable, recycled or reused tons of materials.
Building Circularity - Materials returned
On this section of the results page, you will be able to see your returned materials. In this example you will see that none of the materials could be reused as materials, some materials were recycled or used as energy but by far the largest amount of materials were either down-cycled or disposed of.
Building Circularity - Key Material Groups
In this section, you will be able to see the different material groups used in your projects. We have conveniently grouped similar material types and you will be able to see how each of these material groups contribute to the building circularity score. It will also show you the circularity score of each of the groups of materials. In this example you will see that of the different types of concretes, most were virgin materials, and some came from recovered sources. Concrete usually is down-cycled into aggregate, and as you see in the graph downcycling and use as energy is 100%. Since the downcycling score is only counted 50% in the materials returned score, you see that the circularity score of concrete in this project is 26%.
Design for Disassembly and Design for Adaptability principles
Any material that you have marked for either Design for Disassembly or the Design for Adaptability principles will be listed if you expand these categories by clicking the + symbol to the left of their name. This will help you get an overview of the usage of these principles in your project, and possibly identifying how these principles can be used more often in future projects.