The EN 15804 building product LCA standard: more challenges than benefits?
GUEST POST | In general, the development of standards is a good thing, especially in such a complex environment as building and construction. But not all standards are an unmitigated benefit. This week, we feature a guest post by PhD student Sahar Mirzaie, about her research into the pitfalls and challenges in LCA for the building sector, including the EN 15804 standard.
By Sahar Mirzaie, Sustainable Construction Consultant and Researcher
Buildings are responsible for about 40% of global energy use and can influence up to 47% of the UK’s CO2 emissions in their whole life cycle. In the past three decades, attempts to reduce these numbers have faced many difficulties. My research objective is to assess the carbon and energy performance of buildings throughout their life cycle, to identify the pitfalls of sustainable and low-carbon construction and to propose prognosticating, practical solutions. I am currently pursuing a PhD degree at the Centre of Excellence in Sustainable Building Design at Heriot-Watt University in Edinburgh.
When it comes to buildings, the challenge of doing a comprehensive LCA grows massively, particularly considering the complications introduced by a building’s extended lifetime and the many processes, materials, products and stakeholders involved. Due to this level of complexity of doing LCA for buildings, the building industry has not yet benefited from LCA as much as other industries. As part of my PhD research, I investigate the reasons for this and evaluate the current tools, methodologies and regulations in order to highlight the best strategies going forward.
Environmental Performance Assessment of Buildings and the Need for Standards
In 2004, the European Commission foresaw the need for EN standards for the integrated multi-criteria assessment of buildings, civil, and construction products and services. This was needed to encourage transparency and communication about the environmental impacts in the life cycle of buildings and to overcome the current barriers in construction sector trades. Therefore, a suite of standards was developed to measure the sustainability of construction works in accordance with EN ISO 14025 and EN ISO 14040/44. This suite included EN 15804, which has become the reference standard for developing reliable and verifiable LCA-based studies, reported in the format of Environmental Product Declarations (EPD; ISO type III). EN 15804 advises on the core rules for the product category of construction products, services, and processes. Since EN 15804 does not present approaches for the inclusion of EPD and aggregation of impacts at the building level, EN 15978 suggests calculation methodologies for that.
EN 15804 – Benefits and Shortcomings
1) Understanding an EPD
Some of the main benefits and shortcomings of EN 15804 are directly derived from the standard’s original purpose: raising awareness. Therefore, an EPD complying with the standard transparently reports the environmental impacts of construction products in all the impact categories for each life cycle stage, but without any weighting or normalization. This makes it hard for people who aren’t LCA practitioners to understand, benchmark, and interpret the results, reducing the possibility of effective communication with consumers. This type of impact assessment simply involves classification and characterization, and these studies do not necessarily interpret the results to identify the hotspots, advise on limitations, or give recommendations.
2) Methodological Considerations
For simplicity and harmonization, EN 15804 standard avoids subdivision of the rules and provides the same core rules for all construction products, services, and processes, regardless of their technical and functional performance. This is a drawback for comparison of environmental impact of products. A comparison of EPDs is meaningful only if those products can function interchangeably. For instance, the performance of two types of thermal insulation used in a roof should only be compared if they provide similar heat transfer resistance (R-values) over a similar service life.
Moreover, EN 15804 may provide several alternative calculation methods for one decision point, for instance for system boundaries, data sources, and allocation choices. While this simplifies the calculation challenges, the variety of methodological choices can sway the outcomes and reduce consistency and reproducibility.
In EN 15804, the processes of waste management need to be assigned to the product system that generates the waste. This means the impacts and benefits of recycling, recovery or reuse during the production stage are beyond the system boundary, and reporting them separately is only optional. This leads to criticism of EN15804 in that it only encourages the use of recycled materials, but does not encourage designing for recyclability.
3) Environmental Impact Categories
EN 15804 only includes 7 impact categories: global warming, ozone depletion, photochemical ozone formation, acidification, eutrophication, mineral and fossil resource depletion, and non-fossil resource depletion. Certain predefined parameters are wholly missing from the scope, including water resource depletion and toxicity to human health. Consequently, the outcome of an LCA compliant with EN15804 would not reveal a comprehensive environmental performance portrait.
Problems with LCA at the Building Level and the Way Forward
After years of effort following the release of this standard and after numerous EPD studies, EPD is still not an integrated part of the streamlined building LCA. The current EPDs are inherently incomparable and cannot help much with the selection. Building sustainability certification schemes such as BREEAM see only a minor value of EPD in material and product procurement.
In the near future, EPDs are expected to be an integrated part of the design process through routine incorporation in building LCA studies with the use of Building Information Modeling (BIM) models. Therefore, harmonization in EPD programs and branching of the construction product category are essential, facilitating steps.
There are currently more than 28 European EPD programs, all based on ISO 14025 and EN 15804. To address this proliferation and increase the chance of benchmarking, comparability, and harmonization, the EU Product Environmental Footprint (PEF) and ECO-Platform initiatives were established. Moreover, a revised version of the standard, EN 15804:2012+A1:2013, was developed to address some of the above-mentioned shortcomings. Even more complementary steps are required in future revisions to ensure a more comprehensive scope and avoid further divergence. Steps such as including missing environmental indicators, supplementing product categories, more stringent cut-off rules, and a greater degree of methodological specificity.
Have a say in what’s to come
I am currently investigating the current European LCA standards in the building industry to reduce confusion by drawing a more comprehensible picture of all the available methodologies, references, and standard, their pros and cons, and the best ways forward.
I would greatly appreciate hearing about your knowledge and experience with the use of EN 15804 or the PEF method and your experience in LCAs for building and building products. After this thorough review, I hope to develop a simplified flowchart for more straightforward and manageable building LCAs. I aim to make this framework responsive to the current needs and challenges of construction industry LCAs, such as using EPDs for later design stages and in the building’s digital model (BIM model).