My firm has focused on specifying GWP limits by individual concrete strengths, steel types, and other materials, but I see the many advantages of instead setting minimum GWP reductions for the project, based on quantity, compared to the same quantities of baseline materials.
Bidders would calculate their proposed material carbon reductions on bid forms, so carbon criteria can be part of the bid selection. I see that some policies have been working towards that, GSA, WA, (have any done it already?) and perhaps some companies have implemented this into their specifications. @lauren.wingo i just read one of your posts where it sounded like you were working on this–have you done it? Any others? It would be great to hear how people have implemented. Did you provide bid forms to calculate and include the requirements under Division 00? Did you require bidders to provide the information and update again as a submittal during design?
I’m hearing from specification folks in the company that we do not issue Division 00 bid forms for our typical projects, except in rare cases when there is a CM or pre-selected GC or perhaps for some public-entity owners. If you’ve done this already, it would be helpful if you could share how it’s been done!
Hi Scott,
LMN works with the structural engineer, GC, and sometimes potential concrete suppliers to determine how aggressive we can get on specifying concrete GWP reductions. For the last several years we have often specified 30% below the NRMCA levels (more recently below the 2022 levels). However, we specify this across all mixes, giving flexibility for the bidder to be worse in some mixes and better in others. We provide a concrete GWP mix form in our 018113 sustainability section (along with our sustainability product cover sheet).
This has been mostly effective in getting to the reductions required. We do not require this form at bid time, although in some cases we have worked ahead of time with all parties to ensure they are aware and submitting compliant mixes. I’m interested to hear how others approach this.
In some cases where we aren’t completely sure that bidders can meet the GWP criteria we have worked with the GC to include RFP language for bidders that prioritizes GWP reductions and includes it as one of the award criteria; in other cases lower GWP is an bid alternate.
-Kjell
Kjell Anderson FAIA, LEED Fellow
Principal, Director of Sustainable Design
LMN
lmnarchitects.com
M 206 812 6546
O 206 682 3460
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