fly ash concrete in HC

Bill Swanson

Sr. Electrical Engineer

Integrated Design Solutions

LEEDuser Expert

516 thumbs up

May 18, 2012

The 2nd draft had a fine print note prohibiting the use of fly ash in the concrete on HC projects. The 3rd draft removed this note. Comment #3488 from the 3rd draft still asked to remove this fly ash restriction. Then the response from USGBC was that the fly ash restriction on HC projects will remain. I don't see this in the 4th draft. Was this just an 'oops' or will this fly ash restriction show up in the Reference Guide?

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Mara Baum

Partner, Architecture & Sustainability

DIALOG

LEEDuser Premium Member

449 thumbs up

Wed, 05/23/2012 - 01:01

I hadn't noticed this fine print - thanks for raising the issue. Having done a fair bit of research into the flyash and health question I find it a little odd that USGBC take an inconsistent stand between rating systems. I understand the health logic, but why forbid a product in one rating system but award it in another. With other substances of concern addressed in LEED HC (e.g. heavy metals), it's not as though LEED NC actively gives you points for using them.

Bill Swanson

Sr. Electrical Engineer

Integrated Design Solutions

LEEDuser Expert

516 thumbs up

Wed, 05/23/2012 - 13:01

I actually commented in the 2nd Draft to have this note removed. From my own 10 minute search on Google I found a study showing that after 2 months of curing there is no difference in emission from portland cement vs fly ash cement. My concern was that this was being used as a foot hold into LEED and that the next version would "align" the systems and ban the use of fly ash completely. Just want to make sure this ban doesn't slip in thru the back door via the Reference Guide.

Susan Walter

HDR

LEEDuser Expert

894 thumbs up

Wed, 05/23/2012 - 13:50

I have commented to have this removed as well. I understand the need to not use products with certain chemicals. But I see the fly ash as a by-product and in Maryland/West Virginia/Virginia we aren't going to stop burning coal for a long time. Wish that wasn't the case but it is reality. I would much rather use that by-product to replace a manufactured product. In HC the issue is that there is a MR pre-requisite to eliminate mercury and the fly ash from coal plants does contain mercury. Until the MR pre-req migrates to other LEED programs, the fly ash restriction will likely stay with HC.