Life Cycle Assessment (LCA) in Construction

Have you ever wondered about the materials used in the construction of your house or your workplace and the impacts they have on the environment? Is the house you live in environmentally friendly? How about the chair you sit on for those very long but yet amazing hours at work? And more importantly, what are the techniques used to know exactly what the impacts they have on the environment? This is exactly what a Life Cycle Assessment in construction aims to answer for you.

What is a Life Cycle Assessment in construction?

First things first, let’s define the notion of life cycle. This concept refers to the entire service life of a material- which could be 5/10/60 years, depending upon the material, assembly or component. The life cycle starts from the extraction of raw material, the product is then manufactured and processed into finished goods and transported to its final destination, which could be your next-door factory in order to be distributed within the local, regional or in the global market. The product is used, repaired and maintained. Finally, post operational stage, when the product has reached its end of life, instead of going to waste, it can be recycled or reused elsewhere. This particular concept of life cycle, called cradle-to-cradle, is often referred to within the concept of the Circular Economy. However, if the product goes straight to landfill for disposal, we will talk about “cradle-to-grave” which unlike the “cradle-to-cradle” concept, is a linear process and not a sustainable approach.

Not so clear? For example, for a building, consider the basic framework, i.e. a core and shell made out of concrete, steel, and timber. Taking into account the timber used within the building, its life cycle commences from raw materials sourced from forests, that is extraction from trees. Therefore, the life cycle analysis of timber follows the piece of wood from harvesting, manufacture, construction, operational phase of the product to the end of life stage, which is recycling and disposal.

Now, how about its assessment? Life Cycle Assessment in construction will evaluate the environmental impacts throughout the entire life cycle of the product, including upstream and downstream processes associated with the production and disposal. Environmental impacts comprise all extractions from the environment and emissions generated. The guidelines for conducting a Life Cycle Assessment are derived from the International Organization for Standardization, the relevant standards being ISO 14040 and ISO 14044.

Were there any fertilizers involved? How much water and energy were used during each stage of the life cycle? Were there emissions from transportation (land, rail or air freight) of the product from extraction to installation? If yes, how can these be reduced? In other words, the life cycle assessment is an efficient way of assessing the environmental impacts of products, materials, assemblies, and components used and installed inside a building during its entire life cycle. As stated by the National Risk Management Research Laboratory of the United States Environmental Protection Agency (EPA), “LCA is a technique to assess the environmental aspects and potential impacts associated with a product, process, or service, by:

  • Compiling an inventory of relevant energy and material inputs and environmental releases
  • Evaluating the potential environmental impacts associated with identified inputs and releases
  • Interpreting the results to help you make a more informed decision.”

In addition to integrating waste management and pollution studies, the actual purpose of the assessment is to get a brief overlook of the building performance by analyzing the environmental data of each material for various impact categories, namely greenhouse gas emissions, ozone depletion potential, acidification, and eutrophication. These are detailed below:

  • Global Warming Potential (GWP), also referred to as the carbon footprint. It refers to the ability of each greenhouse gas to trap heat in the atmosphere, therefore gradually heating the planet. The EPA states that “The Global Warming Potential (GWP) was developed to allow comparisons of the global warming impacts of different gases. Specifically, it is a measure of how much energy the emissions of 1 ton of a gas will absorb over a given period of time, relative to the emissions of 1 ton of carbon dioxide (CO2)”.
  • Ozone Depletion Potential refers to the thinning of the ozone layer in the upper atmosphere.
  • Acidification is a broad term that refers to the “process by which aquatic ecosystems become more acidic.” (EPA). The increase in acidity level in the oceans are mainly caused by generated gases and is detrimental to aquatic species of flora and fauna.
  • Eutrophication, or the increased production of algae, results in a decrease of oxygen in a body of water mainly caused by “nitrate fertilizers which drain from the fields, nutrients from animal wastes and human sewage” as stated by the EEA.
  • Smog Formation is caused by the reaction of sunlight with nitrogen oxides (primarily from vehicle exhaust) and volatile organic compounds (from paints, solvents, and fuel evaporation) which “have negative impacts on the health and welfare of the world population” (EPA).

In order for an LCA to be conducted, an accurate bill of quantity for each material as well as a solid database from the operating software should be available. The software will enable the user to evaluate the impacts of the chosen materials on each impact category. This can help in the analysis of materials based on their environmental impacts (based on their properties and extraction location), and considering switching to those with lower impacts, such as those available locally, or those regionally manufactured. These will have a lower carbon footprint, hence positively impact the LCA of the building and making it more environmentally friendly.

Why the science of LCA should be mandatory in the construction industry

As you may know, climate change has become a crucial global concern over the past few years, especially since the Intergovernmental Panel on Climate Change (IPCC) report has alarmed us with the +1,5°C scenario, assuring that the average global temperature will rise by 1.5°C to 2°C on the planet, if there is no significant action taken to drastically reduce carbon emissions. It is a fact that industrialization in the late 1800s, rural exodus, and urban sprawl have resulted in the need for increased housing and construction demands.

Considering this trend to be on the rise as the world faces overpopulation, the construction industry should be THE biggest industry that must strive to reduce its carbon footprint, which can be initiated through the use of LCA during the pre-design phase of new as well as retrofit projects.

How you ask? Good question! You see, in addition to measuring the environmental performance of the materials used inside the building, LCA can be used in the early design phase to identify the building’s environmental hotspots related to the impact categories being considered. For the materials that showcase a higher percentage of environmental impacts, Life Cycle Assessment of sustainable building materials can help you find alternative materials with a lower impact. In this way, projects can reduce environmental impacts, waste generation, be energy and water efficient, as well as optimize the costs.

How Alpin uses LCA to help projects lower their carbon footprint

At Alpin, promoting sustainable solutions for the built environment is our main focus, and LCA is one of them. Indeed, we have helped several projects achieve their targeted certifications by conducting LCA studies in-house to identify the key elements that lead to emissions and how to mitigate their impacts.

One of the latest projects we conducted an LCA for, was an ACE retail fit-out project, located in Dubai. The project covers an area of 3634sq.m. and complies with LEED v4. By quantifying the inputs and outputs of each material, product, and component installed in the fit-out, and assessing their impacts on the environment through an LCA study, we were able to compare different iterations of material options and evaluate which options were the least environmentally friendly. The initial materials planned to be used for the building resulted in having a high environmental impact, the outcome of the LCA helped ACE in finding more eco-friendly materials, and therefore improving the building’s performance and lowering its impact on the environment. Moreover, projects pursuing green building certification such as LEED or BREEAM have the possibility to earn extra points by conducting an LCA.

Challenges we face as construction consultants working with Life Cycle Assessment

Some challenges can be faced while conducting the LCA, especially if you are doing it for a project that’s based in the United Arab Emirates, as most of the materials present in the database are registered in countries outside of the GCC/Middle East region. One of the issues we face as life cycle analysis consultants in the United Arab Emirates is  the unavailability of the data will have a negative impact on the accuracy of the results. In addition, gathering data for each material used inside the building (exact references include physical and chemical properties) can be difficult, and imprecise information may greatly impact the accuracy of the final results. Finally, the iteration run outcome will not directly pinpoint towards the exact product that should be replaced, and which alternative product or material is most cost-effective and suitable to be used instead. A detailed analysis and interpretation must be done to conclude which one(s) are most suitable.

How to incorporate this further?

The importance of Life Cycle Assessment in construction is underestimated in the Middle East region. What if all construction companies were to incorporate it into the design phase and choose materials based on its results? Well, if all projects were to conduct a Life Cycle Analysis, there would be a greater accuracy in measuring the environmental impacts of each building, and therefore a greater chance to monitor the impact, to finally reduce it. Globally it can help the environment by reducing emissions drastically. Now, this might not look like a big deal to you. But think about it, what if LCA became mandatory for each project conducted in the Middle East region – the impact would be commendable.

This article was jointly written by Sadaf Ghalib and Adele Guidot.