Critique of Milstein Hall: Sustainability

Jonathan Ochshorn

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contact | homepage | index of selected writings | Critique of Milstein Hall contents and introduction
Sustainability contents: 1. introduction | 2. sustainable sites | 3. water efficiency | 4. energy & atmosphere | 5. materials & resources | 6. IEQ | 7. innovation | 8. Cornell's vision | 9. conclusions

4. Energy & Atmosphere

Prerequisite 1: Fundamental Commissioning of the Building Energy Systems. It is not enough to specify energy-conserving equipment and to design energy-efficient buildings: one must also make sure that such designs and equipment are actually installed and operating as intended. That a properly functioning building is not necessarily the outcome of an ordinary design process is itself a remarkable admission; in any case, "commissioning" involves the following operations concerning the main energy-using building systems (i.e., HVAC&R, lighting and daylighting controls, domestic hot water, and renewable energy systems, if any):

  1. A so-called Commissioning Authority (CxA) must be designated with experience in such things.

  2. This CxA reviews the two documents that define project objectives: the "Owner's Project Requirements" (OPR) and the "Basis of Design" (BOD), the latter of which is prepared by the design team.

  3. These requirements (for commissioning) must be included in the construction documents, so they are an official—contractual—obligation of the owner and contractor. Most of the commissioning details end up in a section of the General Conditions of the specifications as well as in the specific specification sections (also bid forms and drawings where applicable) related to the particular commissioned items.

  4. A specific commissioning plan must be developed.

  5. Adequate installation and performance of the main energy-using systems must be verified, per commissioning plan.

  6. Finally, a commissioning report summarizing the findings must be produced.

Note that the building envelope—including the stone veneer, floor-to-ceiling glass, stamped aluminum soffit panels, etc.—is excluded from the commissioning requirements, although the LEED commentary suggests that "significant financial savings and reduced risk of poor indoor air quality" can be achieved by voluntarily including it within this prerequisite.

Prerequisite 2: Minimum Energy Performance. This prerequisite prevents projects from obtaining LEED certification without at least meeting minimum guidelines for energy efficiency established by ASHRAE/IESNA Standard 90.1-2004. Included are requirements for the building envelope, HVAC, service water heating, power, lighting, and other equipment that are adjusted according to climate zone. Because these minimum requirements are already requirements of many state building codes, this prerequisite doesn't really force LEED-certified projects to meet energy-conservation goals that they wouldn't be compelled to meet in any case.

Even so, Milstein Hall apparently only barely satisfies this energy performance prerequisite. As discussed previously with respect to Table 1 in the Introduction, Milstein Hall is projected to be 2 percent more efficient than current Code-mandated energy standards. However, it achieves this dubious energy distinction only by leaning up against two existing buildings (Sibley and Rand Halls) along parts of its southern, eastern, and western facades: both heating and cooling loads are reduced for Milstein Hall since approximately 28 square meters (3,000 square feet) of its "exterior" wall area does not actually face the exterior. As a free-standing building without the benefit of such shared wall surfaces, Milstein Hall would experience greater heat loss and heat gain, and would have difficulty meeting even the minimum standards of ASHRAE 90.1-2004.

Prerequisite 3: Fundamental Refrigerant Management. This prerequisite is, like No. 2, difficult not to meet for new construction, as chlorofluorocarbon (CFC) -based refrigerants are no longer used in new HVAC&R equipment. Milstein Hall is connected to Cornell's campus-wide lake-source cooling system, so that refrigeration equipment has been already eliminated in any case.

Credit 1: Optimize Energy Performance. While there are three "compliance paths" for this credit, there is only one way to get up to 10 points for energy-efficiency: one must create an energy simulation (a computer model) for the proposed building and compare it to what is called a "baseline" condition. This is immediately very strange: how can a "baseline" design be created when every building—especially an idiosyncratic structure like Milstein Hall—is unique? Before describing what such a "baseline" building is under the LEED guidelines, a simpler and more rational basis for judging energy efficiency can easily be imagined: one could simply assign energy points based on a project's projected energy use (e.g., the number of BTUs consumed per hour per square feet) for a particular building type in a particular climate zone. Projects that used less energy per square foot would get more points. Adjustments would be made for building type (lab vs. hotel vs. office building, etc.) and climate zone.

Rather than judging energy use in this straightforward way, LEED's Credit 1 method compares the proposed building, not to objective metrics based on the rate of energy consumption, but to an imaginary "baseline" building that is designed just like the proposed building, but even more thoughtlessly. Using standard light framing and insulation, with windows equally distributed on all four sides, and the orientation varied, an average "baseline" energy value can be computed. If the original design fundamentally made no sense from an energy standpoint, then the baseline design will almost certainly make even less sense. In this way, even foolish design strategies can be labeled "energy-efficient," to the extent that their thoughtless original proposals perform better than their even-more-thoughtless baseline brothers.1

There is one additional aspect to this LEED energy-efficiency credit that makes no sense from an environmental standpoint. Energy use, or efficiency, is not measured within the LEED system by computing how much energy is used. Nor is it measured by evaluating the negative environmental impacts of such energy use. Instead, it is measured by cost. This means that proposals that cost more to heat and cool than their standard baseline variations will not be rewarded with LEED points, even if costlier approaches have environmental benefits compared to the baseline. The market-driven ideology that defines the LEED system makes cost the ultimate arbiter of virtually all environmental questions, notwithstanding the almost embarrassingly obvious fact that it is precisely this market-driven thirst for profit that is responsible for most of the planet's environmental problems in the first place.

Milstein Hall will get six "Credit 1" points based on energy-cost savings of 28.58% over its baseline design (the maximum 10 points for this credit requires energy-cost savings of 42%). These points are based on the energy efficiency of the thermal envelope (including its high-efficiency glazing), reduced interior and exterior lighting power density (including occupancy sensors that don't seem to be actually in use), passive chilled beams, radiant floor heating, heat recovery, and VAV air handlers. The envelope model presumably does not account for substantial thermal bridging along the entire length of seismic expansion joints separating Milstein Hall from the existing buildings it connects to, nor substantial thermal bridging due to the continuity of uninsulated steel columns originating on the building's exterior, nor substantial thermal bridging due to shelf angles supporting stone veneer panels that cut into rigid insulation panels, nor substantial thermal bridging due to metal bollards above underground spaces that interrupt rigid insulation (Figure 1), nor numerous discontinuities in the building's air barrier that permit substantial air leakage. Thermal bridging in Milstein Hall is illustrated and discussed in the video linked from Figure 2.2

thermal bridging and heat loss around metal bollards at Milstein Hall, Cornell

Figure 1. Perfect circles of melted snow indicate heat loss and thermal bridging as metal bollards interrupt sub-slab insulation at Milstein Hall. Photo by J. Ochshorn, Jan. 2013

Figure 2. Construction video discussing thermal bridging in the context of Milstein Hall's stone veneer and aluminum soffit (video by Jonathan Ochshorn, 2012).

Credit 2: Onsite Renewable Energy. One to three LEED points can be awarded by obtaining 2.5%, 7.5%, or 12.5% of the building's energy (again measured in units of cost rather than in units of energy) on-site (e.g., from solar, wind, geothermal, biomass, bio-gas, or low-impact hydro sources). Systems can be either electrical (e.g., wind, hydro, photo-voltaic, etc.); geo-thermal (deep-earth water or steam generating either thermal or electrical energy); or solar-thermal (active solar). In other words, sustainability is measured by the cost of renewable energy, rather than by its environmental sustainability. For example, as photovoltaics get cheaper, LEED gives you fewer points for using them, since a given amount will "save" less money. Here's a hypothetical comparison:

Case 1: Proposed building uses $875 fossil fuels (95% energy used) + $125 renewable energy (5% energy used). Total energy cost = $1,000, of which 12.5% of the cost is for renewable energy, resulting in three LEED points (maximum possible). The actual percentage of renewable energy used is 5% of the total.

Case 2: Proposed building uses $975 fossil fuels (90% energy used) + $25 renewable energy (10% energy used). Total energy cost = $1,000, of which 2.5% of the cost is for renewable energy, resulting in one LEED point. The actual percentage of renewable energy used is 10% of the total.

In the scenario invented above, the cost of renewable energy relative to the cost of fossil fuels has gone down in Case 2, compared to Case 1. Twice the energy is derived from renewable sources in Case 2, compared to Case 1. Which case is more sustainable? According to LEED, Case 1—with only 5% of energy use derived from renewables—is much better than Case 2, for which 10% of energy is derived from renewables. Not only that, but the Case 1 building receives the maximum number of points possible for this credit (3 points) while the superior Case 2 building barely gets 1 point (and wouldn't get any points if the cost of its renewable energy dropped from $25 to $24).

Related to the use of an energy-cost metric to measure energy sustainability is the repeated insistence that market forces (costs and profitability) are consistent with energy-efficient green design. Pat Murphy wonders why "the USGBC and other LEED advocates continue to insist that green buildings with significant energy savings do not 'have to cost more?'"3 His answer is that "if energy-efficient green buildings do cost more (and maybe significantly more), then fewer owners and builders would take the financial risk, being unsure of the market." This then leads to the conclusion, supported by the historic record, that only governmental intervention in the form of more stringent building code requirements—leveling the playing field for all developers—would lead to significant changes.4

Milstein Hall has none of the conventional symbols of "green building" design, not only because its architects eschew such trite forms of expression, but also because they had—at least as manifested in this design—no serious interest in sustainable design. In spite of having an enormous amount of roof area with an ideal orientation to the southern sun, Milstein Hall employs neither photovoltaics nor any other type of renewable energy system. Is this rational from a cost standpoint? Probably. Does this demonstrate a serious interest—even if only an academic-research interest within an architecture department situated within a University with a stated commitment to sustainability—in sustainable (renewable) energy sources? Probably not.

Credit 3: Enhanced Commissioning. This credit, earned by Milstein Hall, is an extension of Prerequisite 1 (Fundamental Commissioning of the Building Energy Systems), adding the following commissioning steps:

  1. The commissioning authority (CxA) must be hired prior to the construction documents phase, must be independent of the design/construction teams, and experienced in at least two building projects.

  2. The CxA must review the owner's project requirements (OPR), the basis of design (BOD), and the design documents no later than the mid-point of the construction documents phase, rechecking later.

  3. The CxA must review contractor submittals.

  4. A "systems manual" must be produced, and a process for training building occupants and operating staff must be created.

  5. CxA must review building operations 8-10 months after substantial completion (handover) or the project, and a plan must be developed to resolve anything within the commissioning scope that is unsatisfactory.

Like Prerequisite 1, the real puzzle with this LEED point is the implicit acknowledgment that buildings are not ordinarily checked out in this way. What is also striking is the fact that no further commissioning is required after 10 months of operation. The building can fall apart and its energy systems can degrade into serious states of inefficiency, but the LEED rating remains intact forever.5

But even more serious, such commissioning does not guarantee that LEED-rated buildings actually perform well. In late 2007, the USGBC released the results of a study it had commissioned to analyze the actual performance of LEED buildings.6 The claim that their results "show average LEED energy use 25-30% better than the national average" was famously challenged by Henry Gifford, who wrote that "what the data actually indicate is that the 22% of LEED buildings whose owners participated in the study and reported their energy data used an average of 29% more energy than the most similar buildings in the dataset that the study authors chose to use as a comparison! Going to so much trouble and expense to end up with buildings that use more energy than comparable buildings is not only a tragedy, it is also a fraud perpetuated on US consumers trying their best to achieve true environmental friendliness."7 This critique has been supported by other experts.8

Credit 4: Enhanced Refrigerant Management. This credit is an extension of Prerequisite 3, to support "early compliance" with the Montreal Protocol (1989 with subsequent revisions) which was developed to protect and heal the ozone layer. It basically adds a concern about global warming potential (GWP) to the concern about ozone depletion potential (ODP) found in Prerequisite 3. To do this, the weighted average annual "life cycle" potentials of the proposed refrigerant in terms of both global warming and ozone depletion, accounting for expected annual leakage, end-of-life loss, and refrigerant charge, must not exceed 100 (where the units combine weight of CFC and carbon dioxide in pounds for OPD and GWP respectively). Small units (window AC or small refrigerators) are excluded. Not using refrigerants at all is another option for compliance. Milstein Hall gets this credit because Cornell's lake-source cooling eliminates refrigerants, not because of any particular design decision related specifically to the building.

Credit 5: Measurement and Verification. This credit is earned by making a plan to measure and verify energy use for at least one year, post-occupancy, using simulation or analysis methods. In other words, it is something that one would probably do anyway in earning the Credit 3 point for "enhanced commissioning." Like Credit 3, it raises questions about why such feedback is not ordinarily gathered, and why the LEED rating survives forever even though this measurement exercise may terminate after one year of occupancy. Most importantly, the credit, while useful in as much as it encourages owners to actually measure and examine their energy use, does nothing to actually create an energy-efficient building: the LEED point is awarded just for making the plan, not for actually meeting any energy standard. Milstein Hall earns this point, in any case.

Credit 6: Green Power. This credit requires that at least 35% of "grid-source" electricity—electricity not produced onsite—is from renewable sources and is produced on a "net zero pollution" basis, for a period of two years. The "green-ness" of the energy is measured per the Center for Resource Solutions (CRS) "Green-e" certification, and includes solar, wind, geothermal, bio-mass, and low-impact hydro.

The actual power purchased need not be "green," if one uses instead renewable energy certificates (RECs), tradable renewable certificates (TRCs), etc. This credit is really designed for projects that need to buy LEED points in order to become certified, or for projects that wish to move up a notch in the LEED rating hierarchy—e.g., from certified to silver, from silver to gold, or from gold to platinum. At this point, Milstein Hall is not buying, but that may change if the credits approved through the USGBC evaluation process generate less than 39 points (the minimum amount for a LEED-silver rating).

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Sustainability contents: 1. introduction | 2. sustainable sites | 3. water efficiency | 4. energy & atmosphere | 5. materials & resources | 6. IEQ | 7. innovation | 8. Cornell's vision | 9. conclusions

Notes

1 There is another big problem with comparing a baseline building to the building as designed: "...many dissimilarities exist, such as size and heating characteristics of the glazing, heating characteristics of other envelope elements, lighting density, and type of HVAC system. However, there are not the main differences between the buildings. The real difference is that the design building almost certainly will be built, and the base building is just an imaginary building" (emphasis added). Inevitable variations in the actual vs. "designed" elements comprising the real building "can cause the energy modeling to be off by up to 15% from the deterministic modeling output... Energy modeling software that compares design and base buildings needs to be revised so that it can allocate uncertainties to the inputs of the design building and present a probabilistic output." See: Javad Khazaii, "Rethinking Energy Modelng," ASHRAE Journal, November 2013, p.79, available online (PDF, accessed Dec. 13, 2013).

2 Links to Jonathan Ochshorn's series of Milstein Hall construction videos can be found here (accessed July 9, 2012).

3 Pat Murphy, The Green Tragedy: LEED's Lost Decade, 2009, Arthur Morgan Institute for Community Solutions, Yellow Springs, Ohio. Also available online here.

4 I develop a similar argument in: Jonathan Ochshorn, "What Sustainability Sustains," Presented at the Hawaii Conference on Arts & Humanities, Honolulu, Hawaii, January, 2008. Abstract published in Conference Proceedings, ISSN# 1541-5899, pp. 4024-4025. Full text is available online here (accessed Oct. 20, 2011).

5 See Note 15 in Part 2. Sustainable Sites, here.

6 The final report was released in 2008: Cathy Turner and Mark Frankel, "Energy Performance of LEED for New Construction Buildings," New Buildings Institute, March 4, 2008. Online here (accessed Oct. 24, 2011).

7 Henry Gifford, "A Better Way to Rate Green Buildings," undated (but probably from about Spring 2009) found online here (PDF accessed July 9, 2012).

8 Dr. Joseph Lstiburek, principal of Building Science Corporation and an ASHRAE Fellow, writes: "NBI [New Buildings Institute] compared the LEED median to the CBECS [Commercial Building Energy Consumption Survey] mean. Big, giant mistake, one that will haunt the report authors for a long time. If you compared means alone (i.e. averages) you could say LEED buildings performed about 15 percent better than typical buildings constructed at the same time. But that is misleading considering the scatter of the data. Let me repeat, LEED buildings are not statistically different than typical buildings, even though their mean is around 15 percent better (kind of like how a political candidate can be 3 points ahead but have it be a statistical dead heat). Aren't statistics great? Anyway, the number is certainly not 24-to-33 percent better. And even if NBI's claims for LEED were true, 30 percent energy savings for what is supposed to be the vanguard green program in the US is not very inspiring. Come on folks, we have to do better.

"Someone had to play with the numbers to make the storyline work and that is just plain misleading. And, surprise, surprise the guy who blew the whistle [i.e., Henry Gifford] is getting trashed.

"So what does this mean? Let us translate—the LEED buildings did not conclusively save any energy compared to typical buildings built at the same time. This is not good."

Joseph Lstiburek, "Mis-LEED-ing" found online here (accessed Oct. 24, 2011).