Ecological Footprint Calculation in Construction

Beyond the direct calculation of CO₂ emitted by human activity, whether it’s an airplane trip, a company’s production chain, or the construction of a house, there is a long list of factors that human activity entails, in relation to the balance and sustainability of our planet.

In construction, the total kilograms of CO₂ emitted are often calculated. For example, for structural timber, there is talk of the CO₂ it has absorbed during its growth process or the CO₂ emitted to transport the material from the production site to the construction site.

But what happens if the felling of this tree was not carried out responsibly with a forest management plan and has affected the ecosystem of the area where it was removed? What happens if, during the transport of the logs, polluting gases beyond CO₂, such as nitrogen oxide from diesel vehicles, which is so dangerous to human health, were emitted? What happens if, during installation, we use a chemical varnish to protect the wood, which during its production process has contaminated water or soil?

The list of environmental impacts from all activities involved in building a house is long and complex. Therefore, it is necessary to analyze them in order to quantify them, improve their processes, and reduce them.

In recent years, a multitude of programs, databases, and methodologies related to the total calculation of a building’s ecological footprint have emerged—from its conception, construction, and use to the end of its useful life.

These methodologies are based on LCA (Life Cycle Analysis), and increasingly, manufacturers are incorporating them into their product specifications through EPDs (Environmental Product Declarations), although in many cases they are not exhaustive.

In today’s article, we delve into this carbon footprint and LCA analysis to provide you with useful tools and help you understand how to begin calculating the ecological footprint in construction.

Ecological Footprint in Construction

The ecological footprint goes a step beyond the carbon footprint calculation, taking into account the life cycle analysis of the activity, a methodology that is increasingly close to being systematized. It measures the effect of habits and customs on the environment, allowing them to be quantified to later define whether an activity is sustainable or not.

Specifically, the ecological footprint of a house represents the area of ecologically productive land or water (crops, pastures, forests, or aquatic ecosystems) and ideally also the volume of air needed to generate resources and assimilate the waste produced throughout the construction and subsequent useful life of the building.

Although the final result corresponds to a unit of area, usually in hectares, the impact categories evaluated are diverse and of different natures: the potential for abiotic resource depletion, the potential for acidification and water eutrophication, the potential for global warming, the potential for stratospheric ozone depletion and photochemical ozone formation (causing the famous ozone layer hole), and the consumption of non-renewable primary energy.

Ecological Footprint Calculation in Construction

While the first part of the article focused on differentiating both concepts, carbon footprint and ecological footprint in construction, to highlight the complexity involved in calculating both. To date, the methodology and calculation of the ecological footprint in construction are not yet fully developed and regulated, so it is more common to calculate a house’s carbon footprint and add concepts derived from LCA.

For example, we will see that many tools end up adding the carbon footprint of the machinery used for its construction, as well as the architect’s trips to site visits.

All calculations are usually based on the availability of a prior database containing values on CO₂ emissions and other environmental issues for each of the project’s materials.

In Spain, we have several private and public associations making significant efforts to generate all kinds of tools. Efforts are also being joined at a European level, and some private companies are generating their own databases and calculation programs.

Tools for Carbon Footprint Calculation

Sustainability and Architecture Association (ASA)

ASA is a pioneer in Spain in terms of research, dissemination, and training on climate change and circular economy applied to architecture. It is an independent, non-profit, open-participation, and neutral association, primarily formed by architects with common concerns and knowledge about sustainability and architecture issues.

In 2014, they initiated a project called ‘Carbon Footprint in Building, a parameter in the construction sector’ together with the Spanish Office for Climate Change (OECC), where they analyzed existing methodologies, databases, and tools to promote and facilitate the calculation of the carbon footprint in architectural projects. With all this, they ended up getting involved in the development of the ‘ecómetro’ application, which we will explain in the next section.

Software Applications

Ecómetro

The leading free application, being the most comprehensive and closest to calculating the ecological footprint in construction, is Ecómetro. It is a specific version for measuring data in housing using the LCA methodology, from construction to demolition. Going beyond carbon footprint calculation, it calculates 4 categories: transport, the construction process, substitution, and energy used.

For this, they refer to the database on life cycles considered ‘the most consistent and transparent worldwide’, called the European Reference Life-Cycle Database. The infrastructure of this database has been generated by a non-profit association called Ecoinvent, associated with the Swiss Federal Institute of Technology Zurich.

It is a database of generic environmental data for construction products and materials, based on manufacturing processes representative of European reality. Specifically, it contains environmental data for transport processes, construction, electricity production, and fuel production/consumption. It also allows for the incorporation of specific information from product manufacturers, such as the Environmental Product Declaration (EPD).

Additionally, they include information on the environmental impact categories mentioned earlier (global warming, eutrophication, acidification, embodied energy, ozone layer depletion, resource depletion, ecotoxicity), as well as the impact on users, i.e., human toxicity.

The application works as follows: project measurements are done in Presto and then uploaded to the application for calculation. The only drawback is the high price of professional software like Presto, whose annual license is around €400.

hueCO₂

Another software application is hueCO₂, created by Tecniberia – the Spanish Association of Engineering, Consulting, and Technology Services Companies – and designed to facilitate the calculation of the carbon footprint of public works construction in Spain. It uses the emission factor database from the Eduardo Torroja Institute with the collaboration of IMAGRAMA, the Ministry of Agriculture, Fisheries, and Food.

Similar to Ecómetro, hueCO₂ allows free use of the emission factor database from the application or downloading it for use in calculation programs like Presto. Furthermore, they provide a user guide for the database that specifies other possibilities, such as consulting individual factors and the option to propose revisions or new emission factors. This is why it has a Technical Expert Committee that validates the carbon footprint of machinery and materials introduced by construction companies.

OERCO2 Project

This is a European project developed by Erasmus+ called OERCO2, an acronym for Open Educational Resource, which has developed the CO₂tool for the specific calculation of the carbon footprint in buildings.

To go beyond the carbon footprint by applying the LCA methodology, this Open Educational Resource allows for unifying the calculations of CO₂ emissions at each phase of the building, in order to obtain an overview of the carbon footprint from its conception and to make decisions on each variable of the constructive process.

The interface of the ‘CO₂ tool’ proposes a series of guided steps to fill in, thus facilitating and simplifying the Carbon Footprint calculation process. They have a database of their own analyses of more than 200 materials and means of transport.

Carbon Footprint

Finally, Carbon Footprint distinguishes itself from other applications by its ability to calculate the carbon footprint of an entire organization, whether individuals or companies.

Its approach to individuals involves a very comprehensive consideration of different daily aspects of their lives, a very enriching exercise that we can all take the time to do. In fact, it includes a certificate that recognizes the compensation we can make to balance our emissions.

In the professional field, beyond a certain company size, the service becomes paid, as all this infrastructure was ultimately developed by a private English consultancy. However, its educational nature is evidenced by offering the same service free of charge to both individuals and small businesses; as well as offering ‘plugins’ to add to websites that allow consumers to instantly calculate the carbon footprint of the product they are about to purchase – such as something as common as buying a plane ticket or ordering groceries for home delivery.

Databases

As we have seen previously, ecological footprint calculation applications in construction, or mostly carbon footprint, are practically based on databases. Therefore, the more detailed these are, the more precise our calculation will be. This is where the number of factors we consider comes into play.

For example, when trying to establish the carbon footprint of a brick, we must go back to the extraction of clay components and the machinery used, not just the energy expenditure or emissions resulting from its firing. Another important factor will be to see who the supplier is and add the transport distance to the construction site.

Today there are numerous databases, all of them constantly evolving. At a European level, we find very powerful platforms, but many of them are paid. In this article, we will look at the options we can access for free.

OpenDAP

EPD stands for Environmental Product Declaration; it is a document whose purpose is to provide quantitative information on the environmental impacts that a product entails throughout its Life Cycle. Nothing new so far, but the good news is that a series of ISO guidelines have been established that systematize and verify this type of document, paving the way for the future requirement of this declaration in the distribution of any product, although for now it remains optional.

This is a process similar to product Safety Data Sheets, thanks to which today we can know what chemicals, for example, the paint we are going to use to paint our wall contains, and consequently how harmful they will be to our health or that of our planet.

Helping in this dissemination and awareness of ecological impact with the appearance of EPDs, OpenDAP unifies all these documents within its inData project, developed by the Eduardo Torroja Institute of Construction Sciences. Its operation is simple: it allows free consultation and introduction of EPDs for construction products, establishing a series of filters to facilitate their location.

ITEC

ITEC, the Construction Technology Institute of Catalonia, establishes the official database of construction prices at the Catalan level, so it is normally used to calculate budgets. In 2004, it went a step further and developed BEDEC, the Structured Database of Construction Elements, developing a section on environmental data. However, for now, it only considers CO₂ emissions.

Precautionary list

While it is not a direct CO₂ calculation tool, it provides a lot of information about the composition and dangers of each of the construction materials we can use in a project.

The Transparency website by Perkins&Will, a famous architecture company founded in Chicago, analyzes materials and their ecological footprint, but has also placed great emphasis on the issue of toxicity, often relegated to a secondary concern.

Its database called the Precautionary list is one of the most comprehensive worldwide regarding human toxicity and ecotoxicity, breaking down chemical components of all types of products.

Friendly Materials

Similar initiatives in this vein of human health include PMMT Arquitectura, a firm specializing in healthcare environments that strongly advocates for the research and dissemination of healthy architecture, both for us and for the environment.

Its website Friendly Materials is another step in its humanistic approach to healthcare and the architecture that constitutes it, analyzing materials from a toxicological perspective. Its website is nourished by materials that manufacturers incorporate in exchange for an evaluation of their products.

Software

The next necessary agent in our calculation of the ecological footprint in construction (or, failing that, the carbon footprint) is calculation software. Within these, there are two types that we should not confuse. So far, we have mentioned Presto software, a type of program that simply serves to take measurements and which we can then implement in IT tools or other programs to perform environmental calculations or economic budgeting – which is its most common use today.

The other type of programs, which we will discuss in this section, are software that applies databases and performs the calculation. Currently, specific environmental calculation programs for housing are practically non-existent, so we will discuss two more generic environmental calculation programs: GaBi and SimaPro.

GaBi

GaBi is known as Life Cycle Assessment Software, meaning it is focused on LCA for businesses, but it can also perform calculations for buildings. Its modus operandi is to model each element of a product or system from a life cycle perspective, equipping companies to make the best informed decisions about the manufacturing and life cycle of any product.

It features an easily accessible and constantly updated database that details the costs, energy, and environmental impact of obtaining and refining each raw material or processed component of a manufactured item. Additionally, it analyzes the environmental impact and offers alternative options for manufacturing, distribution, recyclability, pollution, and sustainability. Its distributor, Sphera, offers a free one-month trial, but its annual price is not indicated anywhere.

SimaPro

SimaPro is environmental calculation software also focused on businesses. It is a professional tool for collecting, analyzing, and monitoring the sustainability performance data of a company’s products and services.

Some of its multiple applications include extracting sustainability reports, calculating carbon and water footprints, generating environmental product declarations, and determining key performance indicators.