When looking for sustainable materials, the first step is to know where their ecological impacts come from. Here are some guidelines. Abundant materials are usually more sustainable than scarce materials.
To make a profit in the 1920’s, a copper mine had to get a kilo of copper out of every four kilos of ore. This meant small mines with high ore grades. But now mines can afford to dig up A HUNDRED kilos of ore to get that same kilo of copper. The other 99 kilos become waste. So today, because copper has become scarcer, mines are much larger and produce more waste than they used to.
Even certain renewable resources are becoming scarce. Some trees, like Caribbean mahogany, are being harvested too quickly and are becoming endangered. When using wood, try to find sources that are certified as sustainably harvested.
Materials like bamboo are called “rapidly renewable,” because they can be re-grown and harvested fast enough to keep up with heavy demand. This often makes them a good choice. You also need to look at the energy and resources that go into gathering a material and refining it into a useful form. It takes about forty megajoules of energy to mine and manufacture one kilo of virgin steel. But it takes nearly SIX TIMES MORE energy to produce virgin aluminum. And when either material is processed, like rolling or extruding, even more energy is consumed. Energy consumed this way is called “Embodied Energy.” Usually the material’s carbon footprint is directly proportional to its embodied energy. But it’s not just energy that gets embodied in a product – other resources like water are embodied in the same way.
A great way to reduce the embodied energy and resources in your products is to specify RECYCLED materials for your designs. Using recycled aluminum cuts the embodied energy by NINETY PERCENT!
Embodied Energy of Materials
A material’s embodied energy is the energy that must be used to extract, transport, and process the material. For a product that doesn’t require energy during use, like a chair, the material’s embodied energy is often the biggest source of carbon footprint and environmental impact.
A great way to reduce embodied energy is to specify recycled materials for your designs. For example, using recycled aluminum can cut embodied energy by 90%. If you’re using recyclable materials, you’ll also want to design your product to ensure those materials can be recovered at the product’s end of life.
Health Impacts of Materials
Materials can sometimes also have negative health impacts, and some materials are regulated for this reason. For example, electronics sold in Europe need to meet the Restriction of Hazardous Substances Directive (RoHS). You can avoid health impacts by avoiding toxins, clearly labeling them when they are used, and designing-in product safeguards like child-proof lids. .
Tools to Identify Environmental Properties of Materials
To find data on the environmental properties of materials, you can use databases published by companies like Granta Design. The Eco-Materials Adviser tool within Autodesk Inventor has an Eco-Impact dashboard which displays data from Granta Design on embodied energy, carbon footprint, embodied water, end-of-life options, and RoHS compliance.
Lifecycle Assessment for Materials Analysis
Conduct lifecycle assessment (LCA) on your design to dive into more detailed analysis that can help inform material choice. While more time-consuming, LCA usually includes more nuanced data on variables like ozone layer depletion, air pollution, water acidification and eutrophication, land use, ecotoxicity, and carcinogens.