Material choices play a fundamental role in designing for a circular economy. By choosing only safe and circular materials, you can ensure that products are safer to both humans and the environment, and the materials used to make them can be reused without causing contamination. The good news is that a wide palette of such materials exist.
Without complete transparency of the chemical composition of materials, choosing the right material is complex. This method will help designers to ask the right questions in order to build a better understanding of the chemical composition, and health and environmental implications of a material they are thinking of incorporating into their design.
This advanced method is part of the Safe & Circular Material Choices series.
In this method, you will…
Approximate time to complete: 1.5 - 2.5 hours
Create a Bill of Materials
Creating a Bill of Materials (often referred to as a “BOM”) is a good way to get an overview of all the different materials in a product. You can use this template as a guide. Start this exercise with a full parts list of your product, identify the materials that make up each part, and the chemicals within each material. Alternatively, in order to complete this method, you can also focus on one material of choice.
Assign a Generic Material Type
To understand more about the materials in each part, it is useful to assign a generic material type for each homogeneous material (see below). Examples include but are not limited to:
Classify the Type of Cycle
After you have identified the generic material type in the previous step, homogeneous materials can be classified as either suitable for a biological cycle or a technical cycle. Designating a material as suitable for the biological or technical cycle depends upon what happens to a product after the use phase.
Materials suitable for a technical cycle cannot be consumed or otherwise processed by a biological system. Metals and plastics are examples of technical materials. These can be dismantled and reused, or physically or chemically transformed after their use phase.
Materials suitable for a biological cycle are designed to return to the environment during or after their use phase. Wood, cotton fibre and paper are examples of biological materials.
Start with assigning each generic material to the appropriate cycle. This will help later in the method as you consider optimising the product for circularity.
To truly understand whether a material is safe for humans and the environment, you need to know its chemical composition. This information is often regarded as the intellectual property of its supplier and thus not easily accessible. It is therefore important to build cooperation and trust within your supply chain.
When in conversation with a supplier, they may send a Material Safety Data Sheet (MSDS). These data sheets, required by the U.S. Occupational Safety and Health Administration (OSHA) for all products, and sometimes used globally, are designed to address occupational safety only and usually provide an incomplete assessment of the chemical hazards in a product. Further exploration is needed to fully understand what’s in it and what the impacts are.
When you have more visibility on the chemical composition of a material, you can start screening it using the MaterialWise tool that will provide crucial information about known hazards.
Substituting one chemical for another isn’t always straightforward, and you need to research the alternatives properly before making changes, as Matteo Kausch PhD from the Cradle to Cradle Products Innovation Institute explains:
Highlight all chemicals of concern that need to be eliminated in the design. When you find a chemical of concern, look for ways to design it out through Safe & Circular Product Redesign Workshop or have a look at the Safe & Circular Strategy Cards.
Another important consideration when it comes to selecting safe and circular materials is determining where they come from, or how they are sourced, also referred to as feedstock selection. Because of the possible negative impacts on the environment and local communities from raw material extraction, selection of feedstock from recycled, reused, or properly managed renewable resources is ideal as they avoid such impacts.
If your material is part of a technical cycle, explore how it can be sourced with circularity in mind:
If your material is part of a biological cycle, explore how this material can be sourced in an ecologically responsible and renewable manner:
When you have selected a safe material and considered its life cycle impacts, explore how the product containing the material would fit in a circular design:
When you have selected a safe material and considered its circular design, you can then reflect on what will happen to the product after its use phase.
For technical materials:
For biological materials, when the product reaches the end of use:
For both technical and biological materials, consider whether any additives reduce the ability to cycle the product in which they are found. For example, a label on a bottle can disrupt the bottle recycling process, or a coating on paper can inhibit its biodegradation. To explore this further, see Safe and Circular Materials Journey Mapping.
The Six Classes videos from the Green Science Policy Institute explain six different groups of substances of concern that all product designers should be aware of.
The Cradle to Cradle Certified™ Foundations programme offers guidance for collecting key information, such as developing a Bill of Materials. It also addresses production practices of renewable energy, carbon management, water stewardship and social fairness towards Basic level certification.
The Advanced Methods on Safe & Circular Material Choices are a collaboration between the Ellen MacArthur Foundation and Cradle to Cradle Products Innovation Institute.