AIA 2030 Reporting - input LCA data with negative (sequestered) emissions

Stephen Endy

Associate

Mahlum Architects

LEEDuser Basic Member

0 thumbs up

April 28, 2021

I understand the AIA 2030 team is hoping for as many firms (and projects) to submit some form of LCA data in the new DDx website this week, in order to learn how the industry is tracking embodied carbon. We have four projects that dabbled with Tally last year, which we'd like to report this week.

Has anyone run into a hurdle where you cannot input a negative number for the kgCO2e/m2 (GWP) field?

One of our projects used Tally design options to compare roof framing members only (steel vs. wood beams and joists). To be specific, we used Tally v2020.06.09.01, run as Cradle to Grave including Biogenic Carbon. Our study applied to a roof area of 11,400 sf, or 1,059 square meters. While it's not the most comprehensive comparison, our LCA report shows the wood framing sequesters negative -49,347 kgCO2e, whereas the steel framing emits positive +23,433 kgCO2e. AKA, the wood framing members appear 3 times better than the steel framing.

In order to submit this to the 2030 DDx, I converted the GWP of the proposed wood design option, divided by roof area in square meters. When I try to submit negative -46.6 kgCO2e/m2, the website shows an error "invalid pattern."

Does anyone know of a workaround, or some other way to communicate the indended results to the AIA 2030 team?

I'm not super adept at all the background data on biogenic side. In concept, it seems like we'd want to be able to track projects which might have negative (sequestered) emissions, as we all work to get our average portfolios toward zero over the next nine years.

Any help is greatly appreciated, especially in the next 24-48 hours before the 4/30 submittal deadline.

Thanks,
Stephen

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Tate Walker

Architect

OPN Architects

LEEDuser Basic Member

7 thumbs up

Thu, 04/29/2021 - 22:36

Hi Stephen, Thank you for tracking embodied carbon and providing it in the new 2030 DDx! This is a good question…I’ll give it a shot. First off, you did everything correct as far as I can tell. However, the DDx is set up to track carbon at a basic level to simplify inputs and encourage firms to adopt the practice. It doesn’t use a ‘carbon comparison’ methodology because the 2030 working group felt there wasn’t enough data to justify a baseline case or savings claims at this point. This will likely change as more data become available. As such, you can only have a positive number to report at this point. I’ll note that the scope is critical – in this case only ‘superstructure’ would apply, and even then it’s only fraction of that category. So, this is a great demonstration of why LCA categories can be incomplete and comparison of model results challenging (or misleading?). Still, I think it’s worthy to track it as it will be a good example to pull out later for use on another project. Definitely check the ‘biogenic carbon’ box and input your findings so that you can remember your methodology when it comes time to do this again. Comparison is important, and I feel like we’re gonna get there, but it will be in phases. I am extremely proud of the working group that built and launched the embodied carbon feature in a very short time frame this last year because it’s such an important aspect of our work. As always, I encourage your feedback to keep us moving in the right direction! Tate [cid:image001.png@01D73D1E.1FB7EE60] Tate Walker AIA | LEED Fellow | WELL AP Director of Sustainability OPN Architects o: (608) 819-0260 | c: (608) 286-9397 | d: (608) 819-0844 | twalker@opnarchitects.com 301 N. Broom St., Suite 100, Madison, WI, 53703 www.opnarchitects.com From: Stephen Endy

Stephen Endy

Associate

Mahlum Architects

LEEDuser Basic Member

0 thumbs up

Fri, 04/30/2021 - 00:16

Thanks, Tate.
It's very helpful to hear your feedback and background about the LCA data collection. I ended up listing +0.01 which is the lowest allowable value on the web form currently. The net impact of our small LCA is negative, whether comparing against steel or not. The wood appears to be 3x better than steel. But it's -2x sequestering, whereas steel was +1x emitting. Like you said, our little LCA was so limited (just roof framing members only in this case) that it is hard to compare with other projects. From recent SDL presentations about the 2030 DDx, I understand this year's reporting is a first pass to collect LCA data, and with inputs submitted from various reporting firms, future DDx iterations might allow different LCA information to be submitted. As our buildings get closer to zero, it may be worth allowing negative GWP numbers for any miracle projects that have an overall net sequestering impact. But that will be a good problem to have! Thanks to the DDx team to all your hard work to develop and share this resource. -Stephen