How green can we make PEMBS?

Hilary, We have done these on some charter school projects for cost savings. Sometimes as just the gym and a couple of times as the whole school. We have really pushed on the envelope performance, daylight, and beauty, among other sustainability aspects. I always wonder if there is mcuh savings in the end when you are going so far beyond what they are intended for. Some of our examples: Benjamin Franklin Classical Charter Public School - Arrowstreet Alma del Mar Frederick Douglass Campus - Arrowstreet Happy to talk in detail. Feel free to call or send me an email. Kate _______________________________________ Katherine Bubriski, AIA CPHC, LEED AP BD+C, Fitwel Ambassador Principal | Director of Sustainability & Building Performance 617.666.7006 Direct Arrowstreet 10 Post Office Square Suite 700N Boston MA 02109 _______________________________________ arrowstreet.com Follow us on LinkedIn | Instagram

These are great questions, Hillary!  Could I tag on another question...? Does anyone out there have experience with applying sustainability frameworks (like LEED, Green Globes, IgCC, WELL, and PHIUS) to PEMBS?  Any big pros or cons to report?

We've used these on a few projects. I don't believe any of them were LEED or otherwise certified. Some thoughts: - For a comparable steel framed building of the same size and number of stories, PEMBs appear to use less steel than a comparable building. However, it's a challenge to quantify and track the steel in PEMBs: they don't give you a lot of information during the design process, never provide a model that you can run through Tally, and don't provide summary information during construction either. To calculate the steel, we've had to create our own model from the shop drawings, which is time consuming. And there's still little info on EPDs or sourcing for the steel so we just have to use industry average. - For the envelope, my frank opinion is that their default z-girt assembly is absolute crap. My preferred wall system is to use insulated metal panels. I feel those provide better thermal performance re: thermal bridging, and better infiltration control. Still not a 'best practice' wall assembly but better than the default. Once you start adding heavy cladding like masonry, you will quickly lose the cost and steel material savings of using a PEMB in the first place, so stay lightweight for the wall assembly. That's especially true on the west coast in seismic zones; in other areas it may be a smaller issue. - coordination and design integration is really difficult. You have to use a 'placeholder' structure all the way until the end, when you finally get shop drawings. Aside from those constraints, we have found them to be a quick and inexpensive structural solution on particular projects.

We designed a project using this system at Knox College.  It won a COTE Top 10 award a couple years ago: https://classic.aia.org/resource/6483965-2022-cote-top-ten-awards

A few thoughts on PEMB’s and air barrier continuity:

• I just finished the air leakage testing specifications for division 1 quality control and testing as we are wrapping up CD’s for a PEMB water treatment plant
• Today I spoke with the senior staff engineer at the Metal Buildings Manufacturers Association (MBMA), about their useful best practices guide- the demo project is not with insulated metal panels, which we are using, but a liner system. He said he has at least a dozen projects that have done 0.4 cfm/sf at 75 Pa.
• In Massachusetts, we have whole building air leakage requirement of 0.35 cfm/sf at 75 Pa; MBMA contends this is possible
• In MA, we have enhanced air leakage option for energy efficiency down at 0.25 cfm/sf, but my building is a water treatment plant and since it’s so process focused, that would be just too much to ask of one building.
• The overhead doors are the locations where folks get most concerned about air leakage. We are specifying an insulated overhead door that has extra gasketing to address these concerns.   

https://mbma.com/energy-sustainability

Are we talking Butler and Armstrong?