Has anyone performed a WBLCA that includes the interior partition walls? We are trying to determine the relative impact of these walls.
In my experience, relative to substructure, superstructure and enclosure GWP impacts, interiors only makes up a small portion of the overall projectâs GWP. For a particular analysis, the interiors makes up 10-25% of the overall GWP.
With that said, the walls (gyp and studs) can make up a large portion of that interiorâs total depending on how many walls are used and their acoustic ratings; ie is it open floor plan or a closed floor plan with a high-demand for acoustic dampening where multiple gyp layers are used. For one particular study, I looked at partitions, flooring, ceiling, and wall finishes as part of the âinteriorsâ and the partitions made up 40-55% of the overall interiors GWP.
Further analysis revealed that with âgreenerâ gyps and studs, we could potentially reduce the GWP by 56%.
Hopefully that gives you some insight on whether or not itâs worth including the walls or not.
I agree that interiors is around 10-25% depending on scope and design. The real challenge with interiors is the refreshes (including walls, ceiling, and carpets, as well as lighting and mechanical) that happen sometimes very frequently and add up to a significant piece of total building carbon.
As one data point, LMN looked at our 2014-5 remodel that is very much open office, and we were able to retain some of the walls for conference rooms and kitchens, so walls are a very minor portion. https://lmnarchitects.com/lmn-research/tenant-improvements-embodied-carbon-study
We are about to publish a more recent Interiors project where we attempted to save as much as possible and use salvaged materials. With low-carbon materials we could have reached around 22%, but by saving many of the existing materials and using salvaged materials we reached 65% reduction (from a baseline of ripping everything out and starting with a âcleanâ floor plate).
-Kjell
Thanks Jaclyn - this is very helpful. Your comment on an open floor plan vs closed leads me to ask another question: Does anyone have a range of interior partition densities for various building types like multifamily, open office, âclosedâ office, rec centers, libraries, etc.? I guess the âdensityâ could be expressed in length of partition wall per unit area of floor.
Your GWP reduction for using âgreenerâ gypsum board and studs of 56% is very large - could you tell us what products led to that improvement? My experience is that the gypsum board generally bottoms out at slightly less than 2 kgCO2eq/m2 (per side) and 3.625 metal stud framing at around 3 kgCO2eq/m2 for a total partition wall GWP of 7 kgCO2eq/m2 (excluding paint).
Bob Redwine
Kjell,
Thanks for your comments. âRefreshesâ and their rate is a big deal; has anyone developed a demountable partition wall (non-glass) that could help reduce this impact?
A related question for you, are you aware of the current end-of-life practices for interior partitions: is the gypsum board recycled and are the metal studs normally recycled?
Bob
âŚinterestingly enough our building (for the TI study) was completed in 1969 with movable metal partitions, similar to this:
https://archive.org/details/Sweets1938Sec202MasterwallsByHauserman
By 2014, they were all removed.
The contractors would know more than I about what often happens with partitions. My general understanding is that the studs will be recycled and the gypsum board will be ground up into something and get at least one more use as a cover layer at the landfill or perhaps in new gypsum boards.
-Kjell
Have you seen the LETI embodied carbon primer? Theyâre doing great work generally, and some of it speaks directly to your question. Mirko Farnetani (embodied carbon lead at SOM) did some work showing that internal walls make up between 3% and 7% of their wbLCA results. Of course, your mileage may vary.
The report is here (the figure I pasted below is from page 26):
Jack,
Thanks for your example from SOM and especially the LETI Primer. I have read LETI articles before but missed the primer - the Brits are doing great work! I found it interesting that LETI attributes 49% of carbon emissions to buildings with 20% of that to embodied carbon. This works out to 9.8% of global carbon emissions from embodied carbon of buildings vs. Architecture 2030âs 11%.
I highly recommend the LETI Primer to others for its treatment of operational, embodied carbon AND circularity.
Bob Redwine
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To follow up on this, I dug into the CLF âLCA of Tenant Improvement in Commercial Office Buildingsâ, 2019 and derived the following:
- The average partition wall GWP for the five projects is about 2.5 kgCO2eq/m2, and this corresponds to an equivalent partition wall spacing of 21 feet in each direction.
- If the partition wall spacing was equivalent to 16 feet in each direction (multifamily??), this would result in 3.5 kgCO2eq/m2.
These numbers are based on a partition wall height of 12 feet - higher than multifamily and lower than commercial projects which are closer 13â6" in my experience. The report is unclear on whether the 12 ft is the ceiling height or bottom of structure.
Bob Redwine
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For A1-A3 GWP:
âtypicalâ: studs = 2.38kgCO2e/kg, gyp = 0.29kgCO2e/kg
âgreenâ: studs = 1.49kgCO2e/kg, gyp = 0.26kg/CO2e/kg
I apologize the units are in kg/kg and not kg/m2 but as you can see the savings is in the studs. These values were from OneClickâs database of materials