Great article however I think a more appropriate title might have been "LCA alone wont give us a zero impact building but without it you've got no chance".
Whole of building LCA provides plenty of counter intuitive results and results that really challenge some peoples way of thinking. This is one of the major reasons there is resistance to embracing it as a good tool for informing the design process. Can anyone tell me how else you would go about understanding all of the impacts of a building and work out how to make them zero? I think if we just called it "cradle to cradle" most of the anti LCA people would be much happier for some reason.
Yes it's not definitive and should only be used as a comparative design tool to help inform the process. It is better to be vaguely right than precisely wrong.
Take for instance a building in Seattle (the origin of some great low carbon designs). The carbon intensity of the electricity network is really low due to being approximately 88% hydro and about 6.5% nuclear and only 2.5% coal. So where an average building might have 20% in embodied carbon impacts you can more than triple it for one in Seattle. Without doing a proper LCA you would never know this and go making very expensive operational energy based design decisions that would have minimal carbon savings (if carbon is what you are targeting and LCA can do much more than carbon as alread discussed).
So no it's definitely not a diversion from the real issue - it is the real issue. A good LCA should start by understanding where the big impacts are and working out how to deal with them first. In many cases this might be the operational energy and an LCA will tell you what parts of the operational energy need attention rather than blindly charging off into small design elements because a checklist told you to.
One thing that was missing from the article is a discussion on "functional units". This is where LCA is at it's most powerful. It allows you to compare two different buildings or different design options on a level playing field. The biggest positive impacts you will often have on an LCA outcome will be in the planning stage where you can maximise the design life of the building and maximise the functionality (more people living or working in a smaller footprint). You might get the full "star" rating with the best thermal performance but if there is only one person in the building and it only lasts 20years it's not sustainable. Functional units like kgCO2e/occupant/year are the best way to remove "green washing" and enable good design decisions to be made.
Our goal was to produce a tool that enabled LCA to be accessible (functionally and economically) from residential buildings upwards. If you're wondering if you should spend $200,000 on the standard building or $250,000 on the "low impact" one the LCA should provide the answer in less than 1% of the capital outlay for the "sustainable" design features. Money well spent.
We really encourage the active critical analysis of LCA (you don't get into LCA unless you are over critical and analytical!) as it is what drives our industry to improve and become more accurate and reliable. "Green washing" was one of the primary reasons we decided to create an LCA tool for buildings!
Arming less informed people in the building industry with reasons to not embrace it as a design tool is not helpful. We are not asking for LCA to be the definitive process rather that it just be used as another cog in the wheel to getting a good design outcome. The nice thing is that we are seeing more and more individuals and organisations embracing it and achieving some really good design outcomes. Not only that we are finding once they have built it and moved in the actual performance is hitting the design target.
Go LCA ;)
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