ODP issue with Fly Ash Concrete?

  • One of our users recently asked this question:

    I just wanted to follow up on this – the concrete with Portland Cement replacement shows an improvement on GWP but worse on a couple of other measures – is this correct? And overall, is it better, worse or not much difference to standard Portland cement??

    Richard Haynes

    And eTool’s response:

    The Fly Ash does lead to some increases in other indicators. I’ll need to establish what that is, but being ODP, POCP and AP I’m thinking it could be relating to transport distances.  I’ll query with our data supplier though.  

    Tim (our data provider) is going to check it out and make sure it all makes sense in the next data release which is imminent. I think keep recommending it because right now GWP is the indicator we need to focus on the most (as a planet). ODP is pretty under control, ozone hole has stabilised and probably closing having peaked in 2006, which is great news. This in itself is a great example of global atmospheric pollution reduction, humans reduced production of CFCs by 99%. The remaining ODPs are relatively marginal in comparison to historical emissions. A good analogy would be to think in 25 years time an LCA of a building might show an increase in GWP of 30% against a business as usual design, but by then the business as usual design might be down to 1kgCO2e/m2/year (currently up at 100kgCO2e/m2/year). So the increase is actually only 0.3kgCO2e/m2/year. So 30% sounds like a lot, but it’s on very small base. Would that increase in GWP warrant scuttling other environmental savings? I guess it will depend on what the other environmental saving is. Nevertheless I think this is a similar situation with ODP, we’ve already reduced Business as Usual by 99%, so a 30% increase on that remaining 1% isn’t something that should necessarily be ringing alarm bells. It would be good to see GBCA follow ISCA’s lead and move to normalised and weighted indicators which boils things down to a single “EnviroPoint” score that is actually comparable.

    We’ve just created a new FAQ on this issue. Please check out this post!

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