Quality and consistency for whole-building LCAs using product-specific EPDsWhole Building Life Cycle Assessment with EPDs
When you evaluate the life-cycle performance of your building, using the datapoints from manufacturers and products in your evaluation will achieve a more accurate result than using average data. Products in the same product category can differ in their environmental impacts with several multiples. This makes it paramount that the real product is used for assessment when data is available. This position paper article explains how One Click LCA achieves that while ensuring robust and comparable results.
Using real data to make real decisions is paramountWhen you are trying to optimize your project’s environmental impacts, what you specify is a very powerful lever. For example, ready-mix concrete for external walls and floors embodied carbon per cubic meter ranges from below 200 kg CO2e to above 500 kg CO2e for manufacturing in the U.S. In case of metal-based products, the embodied carbon ranges are even wider. Between similar products, one manufacturer’s greener manufacturing or supply process can give their product a substantial reduction in carbon and LCA emissions. When you specify products for your project and evaluate their performance using Whole-Building Life-Cycle Assessment (e.g. for LEED v4 LCA credits), using the real data for the assessment is paramount. If you do not use manufacturer data (e.g. EPDs), your LCA will treat a manufacturer using recycled materials, energy-saving materials and green energy supply same as another with virgin materials, conventional equipment, and a fossil fuel-based energy supply the same. This will greatly harm the accuracy of the LCA study, as well as the environment if better suppliers are not preferred. The flexibility of being able to use actual manufacturer data also allows reducing the project’s environmental impacts even in the specification and sourcing phase. One Click LCA database contains over 10 000 construction materials environmental impact profiles, and it’s constantly being enriched with new, qualified data from our LCA database engineers. If you have a subscription to One Click LCA, you can send new LCA data that you want to use, e.g. a new EPD fresh out from a manufacturer you work with to our support team. This data will go through the entire verification process and if it passes, it becomes available as outlined in this document.
Comparability of Building LCA resultsComparability for a Life Cycle Assessment results requires a few things: comparable scope, comparable life-cycle phases for all compared options and technically comparable calculation data and assumptions. On top of this, the data, the scope and the results of the study must be fit for their purpose, for example, to qualify for Whole-Building Life-Cycle Assessment for LEED v4 credits. This article explains how these issues can be tackled to ensure robust, high quality and consistent LCA results for construction works, and in particular, how One Click LCA manages this. One Click LCA ensures this by checking all available LCA data rigorously to ensure they comply with LEED v4 and other requirements (see next chapter). Further, data is set up with corresponding life-cycle models.
Managing materials LCA data quality and consistency – The groundworkGlobally, there are well over 30 EPD programs and numerous LCA and carbon databases. These vary in a number of respects, especially in terms of mandatory reported life-cycle stages and in the definition of the life-cycle scenarios applied to those. For EPD programs, these parameters are defined in Product Category Rules. Some programs only report manufacturing impacts, whereas others report a more complete picture of the product life-cycle. Programs may also vary in other regards, for instance in requiring the use of regional characterization methods for the LCA. To be sure, there are EPDs that do not meet our standards of quality. Those EPDs typically fulfill only the ISO 14040, ISO 14044 and ISO 14025 standards. Most of those EPDs have been published prior to or very soon after the publication of EN 15804 or the more recent ISO 21930, which are the most commonly applied modern EPD standards. One Click LCA policy for such EPDs is a simple one: we do not include those data. One Click LCA’s LCA database engineering team integrate all building materials LCA data that a) is technically and scientifically valid, b) verified by a third-party, or verifiable by us, c) is useful for building LCA end users, and d) is openly available. Data that does not meet these criteria are excluded. We use a 10-point verification method to go through a new data source. (more on this in the chapter below). This is a pass or fail process. Some data sources do not qualify at all at a source level, in such cases, the process stops here. In the case of a pass, we create a set of descriptive metadata to enrich the value of the data, for example, adding technical characteristics to the data. In One Click LCA you can always see the background information of any datapoint you use, including what standards it complies with, what PCR it applies and so forth. All EPDs in the platform are third-party verified. You also can download the EPDs and review the information available in it directly.
Third-party verified methodology for checking data quality in detailWe have built in our data processing and verification tools over 50 checking tools, which perform several hundreds of checks on all new data. We perform extensive data verification with our experienced in-house LCA database team. One Click LCA’s data verification methodology has been third-party reviewed by Building Research Establishment (BRE). The detailed verification methodology is our intellectual property. It covers all requirements in the LEED v4 manual for Incorporation of EPD data in WBLCA Tools, namely:
|Requirement for using EPDs
|Has not expired.
|One Click LCA does not allow choosing expired data. If you start using a datapoint when it’s still valid, it will not be removed from the projects where is used on expiry, it simply can’t be added as a new datapoint anywhere any longer.
|EPD scenarios should be representative of contemporary technologies and/or practice, and the project location.
|We ensure this in our verification process and when setting products in a relevant data domain.
|Reports all indicators and system boundary information modules required by the WBLCA tool.
|Data exclusion criteria. Minimum scope for life-cycle phases is cradle to gate (A1-A3). Additional stages for the life-cycle model are enabled in accordance with regional practices and patterns.
|Characterizes the impact categories reported according to the same LCIA methodology as the WBLCA tool.
|Data exclusion criteria.
|Can be applied to the study period of the assessment.
|Data exclusion criteria.
|Clearly indicates which product (including manufacturer and product name) or geographical region it reflects in comparison to the industry-wide weighted average results of a material or fuel already available in the tool.
|This metadata is made available when a datapoint included in One Click LCA. The industry average product performance is available via benchmarks.
The product drives manufacturing impacts, the building the other life-cycle impactsThe LEED v4 manual states that Additionally, comparability shall be ensured in accordance with Section 5 of the BRE Briefing Paper “Assessing the environmental impacts of construction – understanding European Standards and their implications.“ The mentioned section defines life-cycle modeling implications exactly as One Click LCA implements them. These are shown in the table below, after the example. Consider, for example, glass wool. A manufacturer makes the product and publishes EPDs. When the product is sold, the manufacturing impacts are the actual impacts reported by the manufacturer in the verified EPD. However, the end of life impacts of the same product will be different based on the location where the building is built, as that is the region where it will be disposed of. Our modeling practice ensures this is taken to account.
|Life-cycle module EN 15978/ISO 21930
|Influenced by (BRE paper)
|Included in LEED v4 LCA
|Implementation in One Click LCA based on
|A1 Raw material supply A2 Transport of the materials A3 Manufacturing
|A4 Transport to construction site
|User given distance and transport method OR user-confirmed region defaults
|A5 Construction, Installation
|User-given data or user-selected default
|B1 Use B2 Maintenance B3 Repair
|Via data domain defaults or material specific datapoints
|B4 Replacement B5 Refurbishment
|Via service life either set by the end user or user-confirmed defaults
|B6 Operational energy
|User given inputs
|B7 Operational water
|User given inputs
|C1 Deconstruction, demolition
|C2 Transport of wastes/ demolition material
|C3 Waste processing
|Material properties and regional scenario
|Material properties and regional scenario
|D Reuse, recovery, recycling
|Material properties (e.g. energy content) and regional scenario
All data visible and reported transparentlyIn One Click LCA, the data you work with is visible in your user interface (Business/Expert subscriptions). You can see the metadata associated with a datapoint and have direct download access to the EPD or comparable source right from your user interface. Result breakdowns are also transparently available for a detailed analysis. With the Expert level license, you can also access Green Materials benchmarks to help you identify attractive suppliers and solutions for your needs.
What you see is what you get.You can also filter the data according to your preferences, so you can choose to work e.g. with generic datapoints, only Ecoinvent-based datapoints, and prefer any data sources you like over others. You can search data using categories or free-text search, as you prefer.
Choose the data that represents your project best by using filtersIf a material you aim to use in One Click LCA has unusual properties, One Click LCA provides a notice to inform you of this, to be sure you do not choose an unconventional material accidentally. This may apply for example to screeds that are mixed with an epoxy resin.
One Click LCA groups all data into consistent and comparable data domainsWe group LCA data into a number of regional data domains. An end user of any single LCA tool on One Click LCA platform will only ever use data from one of the data domains at once. This ensures that an end user can’t use data that is not suited for the purpose, or incomparable with other data. When we release data, we also enable a consistent and realistic life-cycle model for the data that is representative of the product as well as the region where it is used. This ensures all comparable products in the data domain will have comparable and consistent behavior when used in building LCA, also when the manufacturer only provided manufacturing impacts.
|Data domain examples
|North American data
|TRACI 2.1-compliant, ISO 14044-compliant, includes all six LEED LCA impact categories and minimum life-cycle stages
|One Click LCA generic data and North American EPDs
|CML-compliant, ISO 14044-compliant, includes all six LEED LCA impact categories and minimum life-cycle stages
|One Click LCA generic data and European EPDs
|National/regulatory data (several different domains)
|Regulatory requirements or mandated LCA data/properties Nationale Milieudatabaase (Netherlands)
|Nationale Milieudatabaase (Netherlands)