I will be submitting more detailed comments directly to the USGBC. The following are just for LEEDUser feedback:
BD+C
SS: Heat Island Reduction
Has the USGBC considered making this credit climate zone-specific? In some climate zones, a darker roof actually reduces gross annual energy consumption at the individual building level. It is recognized that this credit has more to do with reducing heat islands than it does with reducing heating/cooling loads on individual buildings. However, there is something to be said for the aggregate, global effect of reduced heating/cooling loads on many individual buildings. A full LCA may even reveal that highly reflective roofs in heating dominated climate zones (e.g. CZ’s 6 and above) may actually contribute more to global warming than the heat island effect of less reflective roofs would. To my knowledge, such an LCA has not been performed to date. It is also recognized that the USGBC may desire to keep the heat island effect separate from the issue of energy efficiency/global warming within the LEED rating system. For example, the USGBC may see the increased energy consumption in individual buildings associated with this credit as a “trade-off” with EAp2/c1 in terms of contributing to global warming. Either way, it would be good to know that the USGBC has considered this issue and has made a deliberate decision.
WE: Indoor Water Use Reduction
Does anyone know why the rating system does not recognize ENERGY STAR as an option for commercial clothes washers?
MR: General Comment
It seems that the shift of using regional materials as a multiplier (instead of a "stand-alone" contributor) does not sufficiently encourage regional materials that do not also contribute to other sustainable product attributes listed in the MR credits. For example, a project using locally quarried stone floors could not receive credit for the "regionality" of the stone for the "Sourcing of Raw Materials" credit as it is currently written.
As an aside, I think that the common complaint about "too much documentation" for these credits deserves attention, but needs to be balanced. For those around when LEED 2.0 came out, how many manufacturers were making recycled content data available? 5%, 10% at most? LEED always has been a market driver and manufacturers will respond as they have in the past (hopefully!).
MR: Construction and Demolition Waste Management
"Option 2. Reduction of Total Waste Material" should make it more clear that diversion from landfills is not a requirement for fulfilling this option (I assume it is not as 2.5 lbs/SF is a very small amount of waste for most projects).
EQ: Interior Lighting
We are concerned about requirement of three lighting levels for individual occupant spaces. Of particular concern are open office spaces with individual workspaces—a growing trend in commercial offices. It is already a challenge to provide individual-controlled lighting for these spaces (often in the form of task lighting at the desk level). It is not clear how multi-level lighting would be beneficial for individual spaces in an open office where task lighting is already available. Moreover, if task lighting is used, the space is, in effect, already employing three levels of lighting (off, ambient overhead lighting, and task lighting). It is proposed that an exception be made to the requirement for multi-level lighting for individual occupant spaces where task lighting is employed as a strategy.
Lyle Axelarris
Building Enclosure ConsultantBPL Enclosure
64 thumbs up
December 7, 2012 - 9:44 pm
Jeremy,
I agree that the heat island credit should be climate-zone specific, as well as other credits (Cooling tower water, for example). I think USGBC should keep the heat island effect separate from the issue of energy efficiency, as you pointed out may be USGBC's desire. The separation of issues and potential synergies and trade-offs are, in my opinion, a very valuable component of LEED.
However, I have to question the idea of using solar gain through the roof for heating load reduction. Unless it is a pitched roof, are you really getting sufficient insolation during the low-angle winter months to use solar gain on the roof instead of a better enclosure? And is that solar gain making it's way through your roof insulation? Maybe it's because my winter solstice noon solar altitude is only 2 degrees, but it seems to me that in heating-dominated climate zones, if you are getting solar gain through the roof in the winter months, then you simply don't have enough insulation in the roof. Am I wrong? (Again, I think I may be very skewed by my zone 8 location).
My climate-zone concern for this credit is that it makes no sense at Latitude 65 to be concerned about SRI values of roof assemblies but not wall assemblies. The solar noon elevation at summer solstice is only 49 degrees in Fairbanks. Well over 90% of the time, the sun is more perpendicular to the walls then the roof (the sun is less than 45 degrees above the horizon). For heat island reduction in the far north, shouldn't the wall SRI values be more of a concern than the roof? I know that we are in a very unique situation, and the reviewers I've spoken with seem very reasonable. I think a clear explanation in the narrative may allow for a wall SRI alternate compliance path, but some credits are simply not applicable to my location.
Can there be a heating-only climate alternative to the Cooling Tower Water use credit? Can LTc4 and LTc5 (Density and Transit) be assessed differently for urban and rural areas? About 10% of the rating system is contained in those two credits, and they are simply unattainable in many rural areas. I support smart growth, but someone has to work on the farms, parks, factories and military bases. There is no reason that the buildings that these people live and work in shouldn’t be high-performing, healthy, sustainable buildings, driven by the LEED process. But the automatic 10% reduction in point potential (among other unique obstacles in rural areas) can be a barrier to LEED uptake in these areas . Yes, some credits are easier in urban environments and some are easier in rural environments. But that only means that we’re missing opportunities to push the envelope in both locations!
Instead of breaking up the rating systems by building type (Retail, Hospitality, Health Care, etc.), I think refinement efforts should be focused on fine-tuning the systems based on climate and urban/rural differences. I understand these are difficult boundaries to define (and climate change and urban sprawl make these group boundaries change through time), but there seems to be much more potential for addressing sustainability needs, realizing market potential, and accurately assessing the "greenness" of a building if you take into account climate and population density.
And the RP credits simply don't cut it! - especially when they are applied across the whole chapter (which in my case spans over 3,200 miles and 5 different ASHRAE climate zones)
Jeremy Kuhre
Sustainable Buildings & Operations ManagerSustainable Solutions Corporation
37 thumbs up
December 8, 2012 - 1:02 pm
Lyle,
It sounds like LEED is a tough fit for Alaska! Regarding a dark roof's potential to reduce heating loads, you may want to check out: http://www.epdmroofs.org/3.3_Supplement_section_of_An-EPDM-Roof-for-Ever.... Be warned it is an industry whitepaper and high on anecdotal evidence. It does cite one study that used DOE's Cool Roof Calculator that may be worth a look. The paper does reference the fact that roof insulation values have increased by so much, roof color plays a reduced role in energy efficiency (as you also mentioned). Bottom line, I still haven't seen a comprehensive study performed on this question. The concept you suggested of an SRI-based approach to exterior walls is a very interesting one. Again, I'm not sure what all the USGBC has considered in this area...
Brian McCallister
August 26, 2014 - 5:24 am
Hey Jeremy Kuhre I am here to know about EPDM Roofing? Is white form of EPDM is also good for the warmer climate? Like they guys http://www.epdmcoatings.com/index.php say that while form of Liquid EPDM is perfect for the warmer climate to control the temperature? What is your opinion on it?