Tag Archives: Chapter 2 – Building Fundamentals

Five Elements of Green Building

By:  Clarke Snell

This is the first in a series of columns written for New Life Journal on the quickly propagating though illusive animal known as “green building”. These days it seems like there is such a frenzy to do “green building”, that few of us slow down long enough to really say what it is. I’ll remedy that problem right off. For me “green building” grows out of the broader concept of “sustainability”: the simple idea that the way of life we choose must not lead to circumstances that prevent that way of life from continuing. Bees have got it down, rabbits can do it in their sleep, but we humans just can’t seem to wrap our big brains around it. In order to even start moving in the direction of sustainability, I feel that we need to create buildings that balance five often conflicting traits:

Five Elements of Green Building

(1) Low Construction Impact. Building is almost always an initially destructive act. Land usually has to be at least minimally cut and reshaped, holes need to be dug, and materials refashioned to serve the building. A green building minimizes its construction impact on the local ecosystem through careful design that considers the building site as a partner rather than an inconvenience. It minimizes its impact on the ecosystem of the planet by utilizing replenishable materials that cause the least amount of environmental destruction in their use.

(2) Resource Efficiency Through the Life of the Building. After a building is built, people move in and use it. This hopefully long relationship usually constitutes the main period of impact that the building will have on the planet. Heating, cooling, lighting, bathing, and watching re-runs of “Survivor” all require resources that are often non-renewable and polluting. A green building creates the daily indoor environment for its human inhabitants in the most efficient, non-polluting, and renewable manner possible.

(3) Longevity. Creating a building requires natural resources such as construction materials and fuels as well as human labor and ingenuity. The longer a building lasts, the longer the time span before the natural environment will be asked to ante up resources to repeat the process. A green building, then, is designed to have a long fruitful life.

(4) Nontoxic. It’s a true testament to our dire straits that this one even makes the list. As bizarre as it may sound, we have to be very vigilant if we want to create a modern building that is nontoxic to its inhabitants or the environment at large. Okay, y’all, it’s pretty simple: a green building does not poison its inhabitants or the environment.

(5) Beauty. To be simplistic (give me a break, it’s just a short column), a sustainable system is one where component elements work together to create a self-regulating, self-maintaining cycle. The complex tangle of relationships that tend to create such systems in nature develop slowly over eons. Everything on the planet earth developed, changed, and adapted as part of a sustainable system.

Flash forward to today. We modern humans find ourselves out of the sustainability loop. What happened? Simply put, we left home. Once we cut ourselves off from a deep, cultural connection to a specific place, an exact climate, a complex matrix of relationships that slowly developed over time, we left the basic source of our sustenance, our sustainability. Now we are left with the daunting task of trying to rebuild that delicate connection to the web of life.

Hey, don’t look at me. I can’t begin to imagine the delicate negotiations we’re going to have make to get back in the club. It does seem to me, though, that to create a sustainable lifestyle, we need to stay put more of the time and derive more of our social, physical, and spiritual sustenance from our own backyards. For example, it takes a long time to build healthy soil to grow good food; to build a network of friends and compatriots that will be the basis for community; to nurture the trees and other plants that will be part of a house’s cooling strategy. These things simply won’t happen if we aren’t sufficiently seduced by our buildings to stay with them for the many years it will take to turn them into integrated places that nurture both their inhabitants and the environment. A green building, then, needs to be deeply and personally beautiful to its inhabitants, a place that is as hard to leave as a lover and as unthinkable to neglect as your own child.

From Theory to Practice

Okay, we’ve defined the task, let’s build some stuff! Unfortunately, we live in a place called the real world where things are never that simple. The fact is that the five elements I’ve outlined are often in conflict with one another. For example, to save energy using passive solar design on a forested site, you need to create a larger construction impact by cutting more trees to access the sun. On the other hand, cob, a mixture of clay soil, sand, and straw, can have an incredibly low construction impact, but isn’t the best insulator. Cob buildings, then, will often use more energy to heat, than comparably sized buildings using other wall systems. Even the seemingly no-brainer concept of building without toxins is harder than it sounds. When it comes to drain pipe, for example, you’re probably going to use PVC. It’s a non-renewable petrochemical product and highly toxic dioxins are released in its manufacture, but I have yet to find a truly practical alternative.

In the end, “building green” is a deeply personal process in which you make judgments as to how a building will best merge with your own personal mode of survival, be it computer programming or subsistence farming, to create the most beneficial impact on your environment, both local and global. An ideally “green” building, then, must be a very specific thing, matching your idiosyncratic personal needs with the fabric of your exact local environment. It’s a daunting challenge, yes, but what more important goal have you got on your to do list? In the coming months, I’ll be throwing in my two cents worth as to how you might go about creating that strange, beautiful animal known as the “green building”.


Residential Energy Use, House Size and Cost

Why does energy use continue to increase despite the constant appearance of better, more efficient technology?  Given that energy consumption per dollar of GDP is decreasing (energy intensity is increasing), some people might say that energy subsidies are justified, at least in the industrial and commercial sectors.  So, why should energy consumption increase in the residential sector?  By far the greatest single use of energy in the home (almost half) goes towards heating (only 6% goes towards air conditioning) [DOE]–and let’s face it, the climate ain’t getting colder.  If we look at the residential energy use patterns over the years, a surprising trend is visible.  The greatest energy-using states go from the North (in the 1970s) to the South and Midwest.  Something besides a winter storm is brewing.

Price certainly plays a large role.  The states whose per capita energy consumptions were the highest in the last five years of data do have some of the cheapest energy prices in the country  (North Dakota, Kentucky, Nebraska, Missouri, Tennessee, Indiana, Oklahoma, and Alabama had the 4th, 5th, 6th, 7th, 9th, 14th, 15th, and 24th cheapest residential electricity prices in 2007) [DOE].

Another factor to consider is the square footage of the residences, which has also been continuously increasing over the last few decades [US Census].

This doesn’t mean that price per square foot is decreasing, however.  If we look at the median selling prices of new homes over the same time period (discounted to 2007 dollars), this is also increasing [DOE].

It’s no wonder that the current credit crisis started in the housing market.  We’re making bigger and bigger investments on bigger and bigger houses–and then paying energy bills to keep all the extra space running.  Per capita income may be increasing with GDP, but not as fast as home price is rising.  If we divide median selling prices of new homes by median income, the quotient is increasing over the years.

The question is: why do we need all this extra space when household size is decreasing?

Missed Opportunities in Structural Sustainability

April, 2009
Structural Sustainability – discussions of sustainability and preservation as they pertain to structural engineering
Missed Opportunities in Structural Sustainability
Ben Hays, P.E., S.E., LEED A.P. and David Cocke, S.E.

Many structural engineers view the sustainable building movement as affording them little opportunity. Additionally, the predominant metric for measuring sustainable buildings, the LEED (Leadership in Energy and Environmental Design) rating system, offers few points for specifically structural solutions. To date, engineers following the LEED scorecard can recommend fly ash in concrete, recycled materials in steel, and sustainably harvested FSC wood. Beyond that, however, most engineers agree in principle with the comments of a LEED consultant in a recent meeting the authors attended: “As structural engineers, you guys can’t do much for sustainability.” This article argues otherwise, looking at the growing link between the reuse of buildings and sustainability and the role structural engineers can play in this type of design.

In 1987, the Bruntland Commission issued a report to the United Nations that included what has become the most widely accepted definition of sustainability as: “development that meets the needs of the present without compromising the ability of future generations to meet their own needs”[1]. Since that time, most discussion about sustainability has included three aspects: environmental, economic, and social sustainability [2]. The common approach to sustainability from structural engineers (where there has been any approach at all) has focused almost exclusively on the environmental elements, in particular specifying reusable or renewable materials. There is a great need for broader thinking about sustainability from the structural engineering community. As engineers, we can significantly expand our impact on environmental sustainability, as well as contribute to economic and social sustainability, with only minor shifts in our thinking and practice. To do this, we must first understand the concept of embodied energy as well as become more willing to work with existing buildings.
Embodied Energy and Existing Buildings

When a building is constructed, significant amounts of energy are consumed in extracting, processing, and assembling raw materials into the finished product. Studies suggest that a building’s embodied energy ranges anywhere from 15 to 20 percent of its total life cycle energy use [2]. This reality lends credence to Carl Elefante’s adage: “the greenest building is one that is already built”[3]. If a structure is demolished at or before the end of a building’s 50-year service life, all of its embodied energy is wasted. This energy waste is in addition to the physical waste created, as well as the energy required in transporting the physical waste to a landfill. Another increasingly selected option exists for the design team, namely adaptively reusing the building.

Recent projects serves as an example of how reusing buildings makes sustainable sense. The authors completed an adaptive reuse of a 1950s, 2-story concrete warehouse (Figure 1). The building is not on the national or local historic registers and the owner could easily have chosen to demolish it and erected a new, similar sized building in its place. Instead, it was decided to retrofit and reuse the building, though not necessarily for sustainable reasons. Using an online calculator, the embodied energy in the 50,000 SF building is 56,500,000 million BTUs [4]. In addition, the energy required to demolish the building would be 775,000 MBTUs, a small percentage of the embodied energy. Finally, by not demolishing the building, an equivalent amount of energy saved by not having to construct a new building, another 56,500,000 MBTU. While any number of comparisons could be made for this quantity of energy, the total energy represented in the sum embodied energy+demolition+new construction is roughly equivalent to 1,000,000 gallons of gasoline. Ironically, a new energy efficient building would take longer than 50 years for its own efficiencies to equal, and thereby pay back, this same amount of energy.
Figure 1: Reuse versus demo: embodied energy calculations.

The numbers related to a building’s embodied energy present a compelling case for expanding our impact on environmental sustainability beyond specifying materials. The concept of embodied energy does not require a cognitive leap of faith. The challenge for engineers is what Patrice Frey quotes as: “shifting the presumption on stewardship of built heritage to favor reuse” rather than demolition [2]. Many engineers, whether through training or experience, do not like working with existing buildings. This is even more the case in California, where “seismic concerns” regularly trump desires to keep otherwise well-performing buildings. If we want to have an impact on sustainability, we must change this prevailing belief within our profession and be more vocal about our efforts in our industry.
Opportunities for Structural Sustainability

The opportunity presented to engineers at the intersection of reusing buildings and sustainability is significant. The Brookings Institute estimates that, by 2030, the United States will replace 82 billion square feet of its current building stock [6]. Our willingness to work with, rather than preemptively condemn many of these buildings, will go a long way toward contributing to sustainability. Architects, developers, and building owners look to engineers to provide honest recommendations regarding the potential of existing structures. Firms that become experts in working with, rather than avoiding, existing buildings will gain a competitive edge as market conditions and sustainable concerns increasingly favor building reuse.

One might look at the idea of reusing buildings and embodied energy and think that we are merely expanding our impact on environmental sustainability alone. While on the surface this is true, reusing existing buildings also promotes the economic and social aspects of sustainability. According to a report by the Brookings Institute, the decision to reinvest rather than tear down or abandon a building “presents convincing evidence that ‘preservation pays’ when viewed in economic terms.” This payment comes in the form of driving economic growth, job creation, friendliness to small businesses, and promoting high wage jobs. All of these are forms of sustainable economic development when viewed long term. Additionally, reusing existing buildings adds to social sustainability by protecting social diversity and maintaining our sense of place in our increasingly globalized world. Patrice Frey expands greatly on how existing buildings promote social and economic sustainability, and the reader would be well served to read her paper [2].
Conclusions

In closing, we return to the question of how LEED recognizes the contributions of the structural engineer to sustainability. At present, LEED primarily credits environmental sustainability in the form of material specification; recycled content in concrete and steel, and sustainably harvested wood. In its current form, LEED awards the same number of credits for reusing 75% of the building’s walls, floors, and roof as it does for specifying bike racks and showers for 5% of a building’s occupants. At present, it does not address the idea of embodied energy directly and does not take into account the cultural heritage associated with preserving buildings. LEED 2009, which launched in March of this year, gives much greater credit than its predecessor to metrics such as Community Connectivity and Alternative Transportation, both of which favor existing buildings. In addition, there is now an Alternative Compliance Path that specifically recognizes an existing building’s embodied energy. Lastly, a Sustainable Preservation Coalition has been formed to incorporate preservation, social, and cultural values into LEED, though probably not until its next release in 2011 [5].

Admittedly, the choice to reuse existing buildings does not rest solely in the hands of structural engineers though our opinion often becomes the deal-breaker. We must partner with owners, architects, and developers in order to maintain our built heritage. Engineers have a more extensive role to play than merely specifying sustainable materials. If understood and promoted properly, the intersection of sustainability and reusing buildings affords structural engineers a great opportunity for professional development, marketing, and occasion to contribute to a greener future.▪
Ben Hays, P.E., S.E., LEED A.P. is a Design Engineer with Structural Focus, a Structural Engineering firm in Los Angeles. He can be reached at bhays@structuralfocus.com.
David Cocke, S.E. is owner and principal of Structural Focus. David currently sits as the SEAOC-appointed Alternate member of the California Historical Building Safety Board. He can be reached at dcocke@structuralfocus.com.
References

[1] Brundtland, Gro Harlem and World Commission on Environment and Development. [1987]. Report of the World Commission on Environment and Development: “Our Common Future.”

[2] Frey, Patrice. [2007]. Making the Case: Historic Preservation as Sustainable Development. (www.preservationnation.org/issues/sustainability/additional-resources/DiscussionDraft_10_15.pdf, accessed 1/16/09)

[3] Elefante, Carl. [2007]. The Greenest Building Is…One That Is Already Built. Forum Journal. Vol 21, No 4.

[4] www.TheGreenestBuilding.org

[5] Campagna, Barbara. [2009]. How Changes to LEED™ Will Benefit Existing and Historic Buildings. (www.aia.org/hrc_a_200812_campagna, accessed 1/16/09)

[6] Nelson, A.C. (2004) Toward a New Metropolis: The Opportunity to Rebuild America. Brookings Institute. (http://www.brookings.edu/reports/2004/12metropolitanpolicy_nelson.aspx)

Mycelium Insulation

Ecovative Design is producing SIPs panels using dehydrated mushroom roots.

We use fungal mycelium, which is basically the roots of mushrooms. The mycelium acts as a resin to bond agricultural byproducts together into a rigid material. We don’t let the mycelium grow long enough to produce mushrooms. That means you never have to worry about spores or allergens.

mycelium

Mycelium is incredible stuff. It builds topsoil. It digests petroleum. It can be used to kill termites and carpenter ants. It can be used to make fuel and cure diseases. Watch Paul Stamets’ TED presentation:

:: Ecovativedesign.com

Fog Testing for Air Leaks


Energy Design Update Page 7:

One fog-test fan is Marc Rosenbaum, an energy consultant and founder of Energysmiths in Meriden, New Hampshire. “My experience is that if you have a blower-door specification for new construction – so many cfm at 50 pascals – and the test comes in 10 percent more than the specification, the builder will usually ask, ‘Why isn’t that good enough?’ – especially if you are fairly far along in the construction process,” Rosenbaum recently told EDU. “But when you use a fog machine, and you have fog blowing out of a hole in the building, I’ve never had anyone point to it and say, ‘Why isn’t that good enough?’ ”