LCA green building credits

Life-cycle assessment green building credits

Can I use a life-cycle assessment to get credits for my green building certification system? 

We often get asked this question and usually the answer is that yes, you can use LCA for green building credits in most certification schemes around the world.

More and more green building certification systems understand the importance of reducing whole life cycle building emissions, which is what the life-cycle assessment methodology is for. Many certification schemes now include credits that require performing a building LCA to calculate the embodied carbon, other environmental impacts, and life-cycle cost.

Want to know more about building life-cycle assessment and why it matters? Read our guide here.

Not all certification schemes approach life-cycle based credits in the same way. This mean that green building professionals are sometimes hesitant to try these new credits, as they are not sure exactly how to achieve them and how the life-cycle assessment methodology applies.

Keep reading to find out more about how you can use LCA green building credits.

The basics of LCA green building credits

Let’s start with the basic terminology. When you look at LCA green building credits you will likely see mentions of life-cycle assessment (LCA), embodied carbon, carbon footprint, and whole building impact assessment. Basically, all of these terms refer to the same thing: analyzing the environmental impacts of a building.

Building life-cycle assessment is the methodology used to quantify the environmental impacts of a building over it whole life time. While performing this analysis, we measure the environmental emissions of different stages of a building's life, from raw material extraction, to materials processing, manufacture, distribution, use, repair and maintenance, and disposal or recycling.

How are environmental impacts measured? In the case of global warming potential (also known as carbon footprint or embodied carbon) the equivalence unit is based on carbon dioxide and how much heat 1 kg of CO2 can trap in the atmosphere (radiative forcing). All the other emissions are transformed into CO2 equivalents based on their radiative forcing.

Life-cycle assessment enables design teams to learn how many emissions their building will cause through its whole life time while they are still early in the design phase. This way, designers can identify the source of  emissions and make design changes to reduce those emissions before construction starts. For example, an architect might select a different insulation material for their design, or make some design choices to increase energy efficiency based on local climate conditions.

To produce standardized results, the methodology needs to follow specific standards, like EN 15978 and ISO 14040/44 standards.

The credit requires that you show the reduction of building material life-cycle impacts compared to a baseline. You must achieve a 10% reduction in at least 3 different impact categories without increasing the emissions in 3 other categories more than 5%. If the design team can show improvement in all of the 6 categories, you will get an additional exemplary credit.

The analysis focuses on building structures and envelope. For instance, all equipment and technical installations are excluded. Additional elements, such as interior nonstructural walls or finishes, may be included at the discretion of the project team but earn no additional credit.

The baseline building must have the same size, function, orientation, and energy performance but other elements may be changed.

Which life-cycle stages must be included in the analysis?

The credit is based on building material LCA following building life-cycle stages according to EN 15804, and it must include these stages: A1-A3 (product upstream and manufacturing emissions), A4 (material transportation), B1-B5 (maintenance and material replacements), C1-C4 (end of life).

Which environmental impacts does the credit take into account?

The LCA credit for LEED uses all 6 TRACI 2.1 categories. TRACI, short for “Tool for the Reduction and Assessment of Chemical and Other Environmental Impacts”, was developed by the U.S. Environmental Protection Agency and uses input data consistent with local US conditions.

1. Global Warming Potential describes how much a product contributes to climate change. When LCA concerns only this impact category, it’s called the carbon footprint
2. Acidification describes how much product acidifies the environment, which can result, for example, in acid rain
3. Eutrophication describes flow of nutrients to ecosystems, which can result, for example, in algae growth
4. Ozone Depletion describes damage caused to the ozone layer in the stratosphere
5. Tropospheric Ozone describes the quantity of summer smog causing gases emitted
6. Depletion of non-renewable energy resources describes how much fossil resources are withdrawn

The impact assessment methodology (defines units and the method for emission calculations) can be CML (used in EN standards), ReCiPe or TRACI.

What type of data can be used?

Datasets must comply with ISO 14040/44 generic life cycle assessment standards. Datasets that follow ISO 21930 or EN 15804 building product EPD standards are automatically also compliant with ISO 14044. Designers are not required to use product declaration of the exact product that they are planning to buy but technically similar or generic average datasets for building materials may be used.

What is the building’s service life standard?

The building service life is fixed at 60 years.

Which software tools can be used for LEED?

USGBC has changed their policy and does not verify tools anymore. Therefore, only the tools that have been verified years ago may be mentioned as officially verified. Other tools will be accepted via submitting a first project. However, a verification against the required standards can also show compliancy. For instance, One Click LCA has been successfully used for both LEED v3 and LEED v4 so it has already been verified. 

Want to look at LCA credits for LEED v4 more in depth? Read more here.

In the BREEAM certification scheme, LCA related credits have been growing more important over the past years. Depending on the scheme, LCA and LCC related credits can now provide you up to 19 credits.
However, to understand how LCA is used in BREEAM we’ll have to take a closer look at different BREEAM schemes as they have different requirements.

The Mat 01 LCA credit requires that you perform a high quality whole building LCA analysis. In other words, the better the estimated quality of the analysis, the more credits you’ll be able to achieve. The quality and credit potential are defined by two factors: the quality of the LCA tool and the assessment scope, which means the scope of different building elements included in the calculation. The quality of the LCA tool makes up 70% of the credit potential and the element scope makes up the remaining 30%.

BREEAM International (2013/2016), BREEAM España, and BREEAM NOR new construction schemes

Which life-cycle stages must be included in the analysis?

The BREEAM LCA credits are based on whole building LCA according to EN 15978 standards. The only life-cycle stages required are A1-A3 (product upstream and manufacturing emissions), but tools that take into account the full life-cycle, including stages A (product and construction process stage), B (use phase) & C (end of life) get the highest quality credits.

Which environmental impacts does the credit take into account?

The impact category that must be included is embodied carbon (carbon footprint). Other impact categories may be included and the scope will impact the tool quality rating. The best quality tools include embodied water or waste and at least two other impact categories.

What type of data can be used?

The preferred data sources are EN 15804 EPDs. Other sources may be used but that will have an impact on the tool’s quality credits. Generic average datasets may be used and their use does not impact quality if a verified local compensation methodology is in place.

What is the building’s service life standard?

The building service life is fixed at 60 years.

Which software tools can be used for BREEAM?

Tools have to be verified by BRE and the credit potential is calculated by Mat 01 calculator. Each of the schemes and version have their own calculator that contains the scheme-specific material scope and total credit potential.

One Click LCA has been approved for all of the schemes discussed here with the highest potential quality rating. When you choose One Click LCA's software you will automatically earn 70% of the credit potential. The limit for the maximum credits is 85%, which means you’ll only have to achieve an additional 15% by adding different building elements. In practice, this will give you more freedom to choose which of the optional building elements you wish to include in the calculations, while still achieving maximum credits.

Want to learn more about BREEAM LCA credits? Read our guide here.

The BREEAM Refurbishment and Fit-out credit requirement is the same as for the new construction schemes: to perform a high quality LCA. The higher the quality of the assessment the more credits are available. An additional step is required to show compliancy.

No comparative improvement in performance is required but design teams will have to write a short qualitative statement explaining how and at what stages of the design the tool was used and how it helped (or did not help) steer the design process to mitigate environmental impacts, giving examples of specific changes to the building design/specification that resulted. A good way to show the progress is often to compare a few different design options.

BREEAM UK new construction (2011 /2014)
Non-domestic schemes

The requirement for this credit is to perform a life-cycle analysis for the building and to analyze the results to find ways to optimize environmental impacts.

No comparative improvement in performance is required but design teams will have to write a short qualitative statement explaining how and at what stages of the design the tool was used and how it helped (or did not help) steer the design process to mitigate environmental impacts, giving examples of specific changes to the building design/specification that resulted (same as in RFO).

Often a good way to show the progress is to compare a few different design options. Results have to be reported in a specified way separately for each data point.

Which life-cycle stages must be included in the analysis?

The BREEAM UK LCA credits are based on whole building life-cycle assessment according to EN 15978 (the British version BS EN 15978). The life-cycle stages that must be included are: building life-cycle stages A (product and construction process stage), B (use phase) & C (end of life) according to EN 15978, but their content and detail of results may vary between tools.

Which environmental impacts does the credit take into account?

The impact category that must be included is embodied carbon (carbon footprint). Other impact categories may be included and all the results obtained with the tool have to be listed.

What type of data can be used?

You will have to use the IMPACT database or database verified to be equivalent. Generic average datasets may be used for material analysis.

What is the building’s service life standard?

The building service life is fixed at 60 years.

Which software tools can be used for LEED?

The tool has to be verified to be IMPACT Compliant or IMPACT Equivalent. One Click LCA offers both options. The term IMPACT comes from BRE’s IMPACT database, which is an average British building life-cycle assessment database according to EN standards.

• IMPACT Compliant tools use that database and its rules for the calculations.
• IMPACT Equivalent tools have been verified to have equivalent quality compared to the IMPACT Compliant tool. IMPACT Equivalent tools may provide manufacturer specific datasets based on environmental product declarations.

One Click LCA has both an IMPACT compliant and an IMPACT equivalent tool: The IMPACT Equivalent tool uses material manufacturer specific environmental product declarations, while the IMPACT Compliant tool uses the IMPACT database.

Additionally, the IMPACT Equivalent tool focuses on the mandatory credit scope of the materials’ embodied carbon impacts, providing easy-to-understand results, while the IMPACT Compliant tool will include a comprehensive life-cycle assessment with multiple environmental impact categories and very detailed results.

Green building LCA credits in other certification schemes

LCA credits are used in other green building certification schemes, like CEEQUAL and national certifications like DGNB, DK-DGNB, Energie Carbone, and others.  We will update this article with more certification schemes and a breakdown of the LCA credits in all of them.

Want to learn more about LCA credits? Join our of our free webinars!

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 711303.