Understanding LCA – measuring environmental impact in design

Life cycle assessment (LCA) is a powerful tool for understanding and assessing environmental impacts of a product, process or service across all stages of its journey – from cradle to grave.  

For buildings, this means tracking impacts across the entire lifecycle: from raw material extraction (cradle), manufacturing and fabrication, building operation, maintenance, demolition and end-of-life use (grave) of building materials.  LCA evaluates general impact areas like resource use, human health and ecological impacts. It’s like looking under the hood of sustainability to figure out what’s working and where improvements can be made. 

How is LCA performed?

LCA is guided by the ISO 14000 series of environmental management standards, in particular, ISO standards 14040:2006 “Environmental management- Life cycle assessment- Principles and framework”  and  14044:2006 “Environmental management- Life cycle assessment- Requirements and guidelines” which are the two underpinning standards for LCA. 

Generally, LCA includes four steps: 

1. defining the goal and scope of the LCA. These must be clearly stated and must unambiguously describe: 

a. intended application; 

b. rationale for the study; 

c. the intended audience for the LCA; and 

d. whether the results will be used in a publicly-released comparative assertion. 

2. inventory analysis. This requires compiling an inventory of relevant energy and material inputs and environmental releases; 

3. impact assessment. This involves assessing the impact of the identified inputs and releases from step 2; and 

4. interpretation. Interpreting the results and providing decision support based on this. 

Why is LCA important?

LCA provides a quantitative assessment of impact and can help to inform decision making.  In other words, it provides hard data that helps decision-makers understand the trade-offs in design and production. It quantifies the environmental impacts, offering guidance for creating more sustainable buildings and products. 

For example, HERA has two projects where LCA forms a key component of the research: 

• Our $10.3 million MBIE Endeavour Fund supported project on Construction 4.0 is using LCA to evaluate the impacts of circular design on the carbon performance of buildings. This work is being led by Prof. Sarah McLaren of Massey University. Sarah is also pioneering dynamic LCA approaches in Aotearoa New Zealand. This is a novel LCA approach, that takes into account temporal differences in carbon emissions. Our project will be a pilot for the dynamic LCA approach that Sarah is developing. 
• Our steel research levy (HERA) and building research levy (BRANZ) supported project to develop design guidance for low carbon design of steel and steel-hybrid low-rise buildings also included LCA. It helped us to compare the carbon performance of various design changes, against an “as built” reference building. The LCA enables us to determine opportunities to pull out carbon in design. 

How does LCA relate to Construction 4.0?

LCA is the backbone of data-driven decision-making in our Construction 4.0 project. We use this quantitative data source for evaluating and optimising circular design. Like any other data set, Construction 4.0 can use this data to provide evidence-based decision support towards optimal multi-criteria design. For example, it can help design engineers to optimise design for carbon performance, while levers for seismic, affordability and constructability are also being pulled (that is the holistic nature of Construction 4.0). 

Need more information?

If you’re keen to dive deeper, you may be interested to check out Life Cycle Association of New Zealand (LCANZ) who are our local knowledge sharing association in this space. 

You might also like to check out these Stirring the Pot podcasts which delve into LCA and its part to play in Construction 4.0 and low carbon design:

HERA is also close to releasing a key research output of our Low Carbon Design research which is a design hierarchy which provides practical guidance for cutting emissions in low-rise commercial buildings by more than 50% through smart design and material selection. We recommend following us on LinkedIn so you are notified when this free resource is made available. 

Following this, we will also be publishing specific guidance for low rise commercial buildings on our Ngākopa Construction 4.0 Hub and we have plans to expand this work to include more case studies and insights. We’ll also explore other building typologies, planetary accounting considerations and costs associated with various design options.   

Follow us on LinkedIn: 

HERA: https://www.linkedin.com/company/hera-innovationinmetals/ 

Ngākopa Construction 4.0: https://www.linkedin.com/showcase/construction4-0hub/