We are beginning to format a tracking methodology for all the studies we run on our projects. One of the metrics we’ll be tracking scope, overall kgCO2e/SF, etc…
Maybe there are already posts here about all the things to collect, but we’d like to use forethought in our statistics, so the if CLF puts a call out for data or anyone does, we can share universal metrics, but also a clear format for our tracking document.
Any suggestions or references that you can point me to would be great!
The CLF has previously published the “Taxonomy for Whole Building LCA” with their LCA Practice Guide here, which lists some of the important datapoints to track for your building LCAs. The short answer is, every project (and every study) is different, so it’s important to track as much metadata as possible to future-proof your results for many possible applications!
Specifically regarding scope: in assembling a database of many LCAs across our project portfolio, my team has found that it’s absolutely necessary to track the scope of your LCA studies in three aspects:
(1) life cycle stages (it is best to keep track of which stages your study includes in alignment with EN 15978, which is a standard way of defining life cycle stages for buildings)
(2) lifespan (this assumption is key to determining how many cycles of building element replacements are part of your overall calculation), and
(3) building components (we adhere to the same framework that was used in the CLF Embodied Carbon Benchmarking Study, and which is currently being used by the AIA 2030 Design Data Exchange platform - meaning a study can be scoped to include substructure, superstructure, enclosure, and/or interiors).
Outside these three must-haves, the more metadata the better - we also track the software tools we use and their version, whether biogenic carbon was included or excluded from the calculation, the modeler, the project area and typology, the project construction type… you get the idea. The more ways there are to slice and dice the data, the more correlations you can look for in the future - but it is up to you which of these characteristics you would find the most useful.
Thank you for the quick response/insights! This is incredibly helpful, we were already mentally preparing for detailed data collection and you’ve mentioned a few good ones to add!
@iancho
Where can I get access to the parameters used in the CLF Embodied Carbon Benchmarking Study?
I’m noticing our CO2/SF is much lower than the averages that came out of that study, and want to understand the scope + carbon intensity values used in the study.
For our in-house structural system Embodied Carbon database (Phase A1-A3), we are tracking:
Project No.
Project Location
Project Status At Time of LCA
Primary Material
Secondary Material (if any)
Primary Use
Lat. System
No. Stories
Bsmt Levels
Sq. Ft.
% SF for primary use
Tons CO2
Lb CO2 / sf
Lb Conc / sf
Lb steel / sf
@solomon.ives First things first, I’d just make sure to check your units - ECBS reports values in kgCO2e/m2, not /sf.
The longer answer - information about the scope of the LCAs in the database is described in section 3.3 and appendices B and C of the CLF Embodied Carbon Benchmark Study pdf here. The study describes everything much more thoroughly, but I think Appendix C table13 is a particularly helpful summary of the scopes of admitted LCA studies:
Where S = structure, F = foundations, E = envelopes, and I = Interior elements, and the column headers describe life cycle stages included in the LCAs. From a total of ~1,190 LCAs admitted to the benchmark study, 52% (n=619, highlighted) represent LCAs that only consider production stage A for structure and foundations (so, envelope and interior building elements, as well as maintenance and end of life are excluded).
There might be other reasons for why your kgCO2e/sf metric is lower than the ones generated in the ECBS - I would suggest reviewing the tables in section IIIB of Appendix C to identify where your dataset and the one from CLF might be misaligned. For example, the ECBS mostly collected new construction projects - are yours representing renovations? Or, the most common LCA tools used for the studies that make up the ECBS are BATH ICE, Concrete Centre and the EATool - do you use a different tool? To isolate why your intensities don’t match, you could start by reading this appendix, and compiling a list of all the “mismatches” between your dataset and the ECBS one.
That being said, while I know the data is far from perfect, our firmwide database of LCA studies done using Tally (n=61) is mostly in alignment with the ECBS, so far. Let me know what you find out about your dataset - and hope this helps.
For our internal data collection we have two streams of data collection:
Project metadata: location, client, design team members, market sector, construction type, LEED? and rating, building code, stories, GSA, phase, new construction or addition?
Material data: volumes on piles, foundations, slabs, walls, columns, beams and roofs. We include material strength, cement replacement, rebar densities, steel grade etc.
Carbon data: Total CO2, CO2/sf, CO2/seats (stadia), CO2 by element
We have learnt that it really valuable for developing research that we know exactly where the carbon is rather than just giving total numbers. This allows us to really start to look at trends at a deeper level.
