Food pyramids are familiar to all of us. They are visual guides that show us the proportions of foods that we should supposedly eat on a daily basis, in order to stay healthy. Composed of a series of layers with different food types–such as grains, flour, fats, vegetables, and others–, at the base are the foods that should be consumed in larger quantities. Towards the top, each layer becomes successively smaller, indicating the foods that are meant to be ingested rarely. The pyramid can vary according to countries and cultures, but its main purpose is always to provide a guide for a balanced life. There are no prohibitions, but it does indicate some foods that should be consumed with caution because of their impacts on our health.
If we are what we eat, is it possible to also replicate this in the construction industry and our buildings? Using this same easy to understand visual language, the Royal Danish Academy Center for Industrialized Architecture (Cinark) developed the Construction Material Pyramid. The idea was to highlight the environmental impact of the most used construction materials, focusing on the analysis of the first three life phases: extraction of raw materials, transportation and manufacturing.
The digital tool makes it possible to compare the impacts of materials in different categories or between types of materials in the same category. This way, architects can be fully informed about each material or product specification decision in a project. "The goal is for it to provide a simple way to get a quick overview of the relative sustainability of individual construction materials." Through clear and intuitive language, it offers an interactive and tangible calculation tool and at the same time opens the dialogue on more detailed studies of the position of each material in the pyramid and its place in project design.
All items are evaluated from the information in their respective Environmental Product Declarations (EPD), which describes the possible environmental impacts of the material or product through standardized analysis and is developed by Life Cycle Analysis specialists. It is an interesting tool to explore what kind of impact each of the materials and products can have. Below, we list the different kinds of possible impacts:
Global Warming Potential - GWP
The GWP is also what is called a product's "carbon footprint". Since global warming is heightened through the accumulation of gases in the atmosphere, such as carbon dioxide and methane, the GWP calculates how much heat a certain amount of gas can retain in the atmosphere, compared to the same mass as CO2. The higher the value of the GWP, the greater the impact on global warming. In this case, while metal sheets occupy the highest level, organic materials have negative rates, which means they absorb more greenhouse gases than they produce during their manufacturing.
Ozone depletion potential - ODP
Certain gases released from materials during their production can degrade the ozone layer, which in turn decreases protection against radiation in the atmosphere, affecting fauna and flora and even increasing the incidence of skin cancer. For the calculation of the ODP, the gas used as a base is CFC-11, also known as R-11, which is already banned in many countries and used as a foam blowing agent for the production of molded foam panels and spray foams used for isolation. Therefore, the most harmful products in this sense are thermal insulators, while materials that require low processing, such as stones and copper sheets, contribute less to this category.
Photochemical Ozone Creation Potential - POCP
The Photochemical Ozone Creation Potential (POCP) quantifies the relative skills of volatile organic compounds (VOS) to produce ozone at soil level. In high concentrations, ozone can affect the health of humans and nature and may even affect breathing. The POCP is measured using ethylene equivalents (C2H4EQ) as an indicator unit. While wood-based materials remain at the lowest level, EPS insulators and structural steel are the largest emitters.
Acidification Potential - AP
Acidification can cause damage to the ecosystem and especially to plants. This category quantifies the amount of gases responsible for the acidification of soils, terrestrial and superficial waters, its effects on animals, ecosystems and also building construction environments, using the sulfur dioxide equivalents of the indicator unit (SO2 EQ).
Eutrophication Potential - EP
In this case, phosphate is the reference substance, calculated in its equivalents. Eutrophization is the increase in nutrient concentration in ecosystems, which can cause imbalances such as desertification or super fertilization. Steel production, for example, emits large amounts of nitrogen oxides. While this chemical element is vital to soils, too much concentration can affect soil biodiversity and aquatic environments.
The tool is therefore able to compile, in one place and through an intuitive interface, a large amount of data on the most commonly used building materials, allowing designers to quickly understand the impact that each project decision can have on the environment. It is important to note that the data presented may differ from country to country. In this case, the current version of the "Material Pyramid" is available from valid EPD data in northern Europe and/or Scandinavia, and there may be relevant differences for valid data in its place.
Learn more about the tool and make comparisons for your projects on the official website.
