Life cycle assessment
Life cycle assessment reveals more than ever about the impact of building products.
IF you want to reduce your construction footprint, sooner or later you’ll need to dive into the murky world of materials.
Take a deep breath first. It’s a place where everything is connected and the products have different impacts, but it’s hard to tell exactly how they relate to one another, and how big the differences are.
In recent years, we’ve become accustomed to the concept of embodied energy: it’s shorthand for all the energy used to make a product, from the mining and processing of base materials, to the packaging and delivery of the manufactured goods.
Now, life cycle assessment is becoming increasingly common. “Embodied energy measures only the energy aspect, whereas life cycle assessment measures all the environmental impacts,” says Dr Usha Iyer-Raniga, assistant director of RMIT’s Centre for Design. “It’s not just about energy, but also about biodiversity, greenhouse gasses, land use and toxins.”
Tim Grant, from consultancy Life Cycle Strategies, says that the depth and rigour of life cycle research sets it apart.
“Life cycle assessment is an internationally standardised methodology for analysing the impacts of products and services. It looks at the cradle-to-grave impacts, including all the relevant environmental indicators,” he says.
The function of the product is a key part of the analysis: nothing can be viewed in isolation. “The assessment becomes very complicated in building industry, because we don’t use materials as they are,” Iyer-Raniga says. “You’ve got to think about how those materials are assembled together to become a square meter of wall, and how the wall performs its role.”
To help solve the puzzles, she suggests householders ask a lot of questions when sourcing products and materials. “People have to be really savvy. There’s a lot of greenwash out there, particularly in the building industry – not just with materials, but with appliances and furniture as well,” she says.
“You need to think about your needs. Is it a house you want to live in for the rest of your life? Think about using long-lasting materials that aren’t entirely dictated by fashion. Consider where the materials come from, how durable they are and whether they need maintenance.”
So far, not much life cycle information has been available for homeowners. The Australian Life Cycle Assessment Society is working on locally relevant environmental impact weightings and a database of products and services, but the project is progressing slowly.
Eco-product database ecoSpecifier recently launched GreenTag, a third-party certification system based on life cycle assessment principles.
Technical director David Baggs agrees that the strength of life cycle analysis is its breadth. “There are lots of carbon calculators available, but as a society we have to be careful to not create counter-productive outcomes by focussing purely on greenhouse gases,” he says.
Under GreenTag, products are compared against a worst-case business-as-usual scenario. They’re rated in four tiers: platinum, gold, silver and bronze (although bronze signifies a health and eco-toxicity rating, not life cycle analysis).
“Once our new website is launched next year, people will be able to see the products’ key performance indicators,” Baggs says. “They could use it to specify minimum standards for their building materials.”
For a rough guide to good life cycle choices, Grant says there are simple rules of thumb for householders to follow. “Firstly, anything that will improve operational efficiency is worth doing, whether it’s solar panels or light sensors that switch lights off automatically. The environmental impacts of production will nearly always be outweighed by savings during the life of the home.
“The second thing is to reduce the size of everything. Smaller buildings use less material, less energy for heating and have less room for furniture and fittings.”
That means modification or refurbishment is preferable to building from scratch, if it can ensure energy efficiency. Earth building techniques such as mudbrick have very little embodied energy, but to remain ahead of the rest, they must also operate efficiently.
“There’s nothing that has no environmental impact,” Grant says. “After doing life cycle assessment, you come to realise that less is more. We really need to reduce our consumption of everything.”