Enclosure scope : what to include? what EPDs are out there?

I am starting to conduct more LCAs that include enclosure materials and would like to know 1)what people include/don’t include in their material take-off, 2) what EPDs they use for benchmarking in OneClick or EC3

Correct me, but I don’t think LEED v4.1 has any guidance on what is to be included as part of enclosure. The mid-cycle CALGreen code update will include enclosure and says “shall be limited to glazing assemblies, insulation and exterior finishes”.

I am a structural engineer and will do the structural take-offs and then we ask the architects to quantify the enclosure materials since they are more familiar with all the bits and bobs that go into an assembly. I take all the information and conduct the LCA; either combine both structure and enclosure in one analysis or separate it out). In my experience we generally have collected the quantity of the following (either by volume or weight):

-mullions/metal extrusions
-glazing
-insulation (both wall and roof)
-vapor/air/water barrier/membrane
-metal studs
-precast concrete panels
-metal panel
-gyp (interior and exterior rated)
-roofing material

1) Is that too detailed/not detailed enough? What do you include or not include?
2) Are there industry average EPDs to use as benchmarks? We use OneClick to conduct LCAs, do you have go-to EPDs you use as industry averages? I use EC3 as a reference but they don’t have vapor/air/water barrier (or do they?)

Hello,
I like the diagrams from the Kaleidoscope tool which help visualise what is typically included. It is worth mentioning that if there is a wall cavity structure I will include the insulation, which the Kaleidoscope tool doesn’t specifically state. Kaleidoscope: Embodied Carbon Design Tool - Payette

When I select “typical” data I either try to use generic industry average EPDs, or an EPD of a commonly chosen product. So for air barriers I go for Tyvek Commercial Wrap because it is so ubiquitous. The EPD in One Click is: Air and water barrier system, mechanically fastened, 0.0451 lbs/ft2, 0.22 kg/m2, Tyvek (DuPont)

Hope that helps,
James

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I have related questions on what should be considered exterior or structural scope for LEED or for other purposes. Does the CLF’s LCA data collection v2 have guidance on this?

We often split our Revit models by interior fit-out vs. shell + core. While some of the items below exist in the shell+core model, I’m wondering if there is consensus on whether they should be categorized as interior instead?

  • Vestibules (i.e. the interior doors and walls of the vestibule)
  • Vertical transportation–elevators + egress stairs and the surrounding interior walls
  • Interior furring applied to the enclosure walls that is uninsulated and has a separate layer of studs from the enclosure assembly, but it is supporting the interior gyp layer and finish. If this shouldn’t be included, to be consistent shouldn’t we then exclude the interior finish layer from all exterior walls?

Also, when we are categorizing structure vs. enclosure, I was under the impression that load-bearing exterior walls supporting the floor above (which typically exist in both architectural and exterior models) be categorized as part of the structural total, while the remaining materials of the assembly be categorized as enclosure… and for non-bearing exterior walls the studs or CMU should be categorized as enclosure-- is that the right approach?

For separating site work from structure, what criteria is used to decide if a site component is part of the building or not? For example:

  • Site walls/retaining walls are attached to the foundation, function is to support a ramp? How about if the function is earth retention?
  • What about retaining walls to create the ‘moat’ around a building with seismic base-isolators (The retaining wall is arguably part of the structural approach in that case.)