The UT Arlington INTS 5304 Sustainability class has been touring numerous sites and listening to many speakers this summer. Sustainable people and places abound in north Texas. Here are the highlights:
Composting – UT-Arlington:
John Darling, the composter with the University of Texas at Arlington, spoke to the class about composting and UTA’s composting program. Composting is a great application of the maxim to “think globally and act locally.” Food waste and topsoil loss are two global problems that can be addressed with composting.
Food Waste - A study found that about one third of all purchased food goes into the garbage rather than being eaten. One pound of food per person per day is not used, either due to spoilage or poor appearance. The food itself plus the embodied energy to raise and transport it is wasted. In Africa, the losses are early in the process - on farms, and in the harvesting, storage and transportation steps. In the USA, Japan and Europe most of the losses are later in the process, at the retail and post-purchase steps.
Topsoil Loss - Some experts say this is second largest global problem after population growth. Deforestation, overcutting for fuel wood, over grazing, and agriculture practices such as plowing all contribute to topsoil loss. The damage due to erosion is substantial and occurs worldwide. In China and India, topsoil is being lost 20 to 40 times faster than it regenerates.
Compost is a product of controlled aerobic decomposition of organic materials. The organic materials generally can include unused food and vegetation such as leaves, wood, and grasses. These are mixed and provided with water and other management to encourage decomposition into a soil-like product that can be used to enhance topsoil.
The priorities for unused food, from highest use to lowest, are: feed poor people; feed animals; industrial uses such as capturing methane from the decomposition, composting, and landfill. So using food to make compost is good, but only in comparison to sending it to a landfill or letting it rot outdoors. A study found that 47% of all trash in the USA is compostable material, according to Mr. Darling. Increased composting would reduce volume in landfills, and reduce the energy used to haul the materials there.
Soil enhancement with compost increases the soil’s ability to hold water, thus decreasing water needed for irrigation. Nutrients are slowly released from compost and absorbed by the plants. This eliminates the need for chemical fertilizers and pesticides. As fertilizers and pesticides are reduced, so is the contamination in runoff water that enters the watershed. The embodied energy in the manufacture and transportation of fertilizers and pesticides is also reduced. In addition to landscaping uses, compost is also a valuable part of organic farming methods that reduce unwanted chemicals in foods.
John began his composting efforts at UTA five years ago as a volunteer, and it became his full time job. He started making compost from clippings and leaves, delivered from a few groundskeepers. It was a labor of love in the beginning, as he improvised for the water and equipment needed. The turning point occurred when the city of Arlington and UTA combined to obtain a grant from the North Central Texas Council of Governments. This was a solid waste grant, funded from tipping fees at landfills. He used the grant to fund electricity and water service, a shipping container to store tools, and a “bobcat” tractor/loader. With that, he was able to process more materials. Grounds-keepers started bringing more leaves and clippings to him, and UTA kitchens provided pre-consumer food waste. (Food that has been prepared and served to a consumer but not eaten cannot be accepted for composting for health reasons.)
Now, he takes about fifty tons per year of kitchen waste and coffee grounds, mixes it with an equal portion of leaves, and makes about 100 tons of compost per year. One limiting factor is the amount of food waste, as plenty of grass clippings and leaves are available but the portions must be about equal. The other limiting factor is simply the amount of material that can be mixed and hauled by one person and one bobcat. Almost all of the finished compost is used on UTA campus either to mix into planting beds or to use as mulch. This operation is improving the environment at UTA and reducing materials hauled to a landfill.
Connemara Meadow Preserve
The Connemara Meadow Preserve is an open area of land near a suburban area in Allen, Texas. The Connemara Conservancy Foundation owns this site as a land trust. CCF started in 1981 with this property, the Connemara Meadow Preserve, known as The Meadow. The board saw a need to expand land conservation beyond just the Meadow. According to a story about CCF in the Dallas Morning News recently, CCF now works with people in 33 counties of north Texas who own land, to help find ways to conserve or protect the land. In some cases that includes working with commercial developers to protect important habitats. CCF works in a metropolitan area that is almost certain to become even more developed. Designation as a Land Trust preserves land such as The Meadow in perpetuity by a conservation easement.
Frances Montgomery Williams inherited the land as part of a family farm. Her family owns the area surrounding Connemara and is developing it as Montgomery Farm. The Montgomery Farm website describes it as “Situated upon 500 acres of pristine prairie and forest land, Montgomery Farm is truly a model for the environmentally-conscious community of the 21st century. Our goal is the creation of a non-polluting, energy-efficient, and sustainable community whose residents live and work in a place of unspoiled beauty.”The Meadow was described by our tour host as “an island of bio-diversity” in a highly developed suburban area. The Meadow consists of 72 acres of land in Allen, near Bethany and US 75. About 40 acres are in flood plain, and the rest would be ideal home sites for expensive homes similar to the surrounding area, if not for the land trust ownership.
The Meadow is south of Rowlett creek. Near the creek, the ecology is “riparian bottomland” hardwood forest, with undisturbed old growth. Elms, bur oaks, and bois d’arc trees have been there so long that a few are dying of old age. Away from creek the land is “upland forest” ecology, which is dryer, with red oak trees and large open meadows with a variety of grasses.
Our guide explained that the meadow area was probably cleared by earlier owners, because the natural condition for land in that area would be as a forest, not a meadow. Most likely, the land has had a couple of prior uses, cotton farming and pasture land. Cotton farming tended to deplete the soil after about thirty years. Typically in this area, after the cotton farming the land became cattle pasture. The prevalence of Johnson grass is a clue – this grass was good for grazing but was not native to this land, so probably was planted as a pasture grass. Unfortunately, the effort to remove the Johnson grass and reestablish native grasses would be monumental for a volunteer organization.
Other challenges based on the site’s location include the upstream portion of their watershed. That area is now developed with lawns and golf courses. These owners typically use chemical fertilizers and pesticides, and landscape with some invasive and non-native plants. These plants and seeds get washed downstream or transported by birds to the Connemara land.
In spite of the challenges, the Connemara Meadow is a wonderful place, truly an oasis of undisturbed nature in suburbia. Perhaps it will inspire others to consider land trusts for some of their property.
Electronics Recycling - eRecycler
Electronic products account for a very small volume of the materials in landfills, but a very large percentage of the toxic chemicals and metals in them. We stopped at a drop- off site in Plano for recycling electronic devices such as computers, monitors, televisions, phones, vacuum cleaners, and clean microwave ovens. (Appliances that process food are not desired because of smell and cleanliness issues.) eRecycler LLC is providing this recycling service, and the Christ United Methodist Church provides the site monthly. The recycling company charges $5 or $10 per item, to defray their cost for transportation and the crew of six workers to work Saturday. The company can fix some old TVs and if so, they donate them or sell at a very low price to low-income families. They recycle the remainder, by disassembling the components and sending them to other parties that want those items. According to eRecycler’s on-site manager, none of the materials go to landfills, and none leave the USA. They find sources somewhere in the United States that have uses for these, or further dismantle them to extract the minerals or other content. Texas Instruments RFAB
Paul Westbrook, the Sustainable Development Manager for Texas Instruments, hosted our class at the RFAB facility in Richardson. Paul is a mechanical engineer, and he has been with TI for 28 years.. In 2001 he joined the design group to work on energy and resource efficiency. Paul is passionate about sustainability at all levels from the broadest corporate view to the tiniest bit of energy savings in a building.
TI is a global corporation with annual revenues of about $14 billion and over 28,000 employees. As consumers we think of TI branded products like calculators and educational technology, which is only a small portion of the company. The majority of the business is in making the semiconductor chips used inside other products such as smart phones, ipads, LED lights, and wind turbines.
The story of the RFAB facility and sustainability starts at Paul’s home. During the late 1980’s, he built a home incorporating many sustainable features, resulting in very low utility bills. He used the house as an example of the possibilities, and got the attention of some TI executives. They asked Paul if these approaches are scalable to a larger building such as a chip plant. That started the executive support for sustainability initiatives, just before RFAB started.
When the idea of building a new chip plant was being considered, in 2003, TI engaged Armory Lovins and the Rocky Mountain Institute to re-think how semiconductor plants were designed. Many new ideas were conceived by dropping the ideas about how the last one was built, and thinking about better ways in terms of energy efficiency and water efficiency.
RFAB got funded in January 2004 and full design began. Construction broke ground in November 2004 and was completed in May 2006. The construction cost was $320 million. However, at that point the chip market was not in need of another plant, so TI waited to purchase the tools and start production. Finally in 2009, TI purchased the used fabrication tools from an idle plant in Virginia, moved them to Richardson and installed them. RFAB started limited production in January 2010. The cost of the tools far exceeds the cost of a fabrication building, even at $320 million. But the advantage of having a building ready was evident when TI was able to purchase the tools in 2009 and quickly install them without waiting through a design and construction period.
RFAB has a clean room for the manufacturing of 284,000 sq. ft. The entire building is about 1,000,000 sq. ft. The sustainable features are numerous, including general building features such as a white roof which saves about 100 tons of air conditioning demand; sun shades over south-facing windows, solar water heating, waterless urinals, and motion sensors on each light fixture in the office area.
The RFAB site slopes to an onsite retention pond. No city water is used for irrigation. The site is planted with native grasses that they mow only twice per year. Water is reclaimed from the manufacturing process and used as cooling tower make-up water. Condensate from the air conditioning is added to the pond, for irrigation. Bike trails are being built from nearby neighborhoods, and van pools are organized for employees.
Other green features are more technical and specific to the special systems needed for chip manufacturing. Chilled water systems are split into two, with 40 degree chilled water (cooler than typical )used to cool and dehumidify critical areas. Chilled water at 54 degrees (warmer than usual) is used for cooling the general building areas. This results in energy savings over one system with reheating as needed. With less reheating of over-chilled water, the plant needs to operate boilers less, so the emissions are reduced and energy is saved.
The new tools have “mini-environments” that require vacuum pumps to operate. However, at times the vacuum needed is reduced. In older designs the vacuum ran constantly, but at RFAB there are variable speed drives that slow down the motors at allowable times, for another large energy savings.
RFAB was the first LEED semiconductor building. Since then, two more have been built in the Philippines. Mr. Westbrook has now turned his attention to improving the existing buildings energy consumption. Energy consumed per chip manufactured in 2010 is 60% of 2005 levels. Energy use company- wide is down 38% over 5 years ago. Water consumption is down 37%, and greenhouse gas footprint is down by 43% since 5 years ago. These improvements are being made without a large sustainability team, because the message has reached into the organization and many people are contributing ideas and seeking funding for projects.
For existing buildings, TI uses the concepts of LEED EB but don’t pursue the certification. They have 95% recycle rate. Not trying for last 5%, there are better initiatives. Next on that is to look upstream and reduce packaging coming to them.
Paul also shared some of his philosophy formed over the years of pursuing the sustainability agenda:
· Measurement is difficult. LEED is one way that works, not the only way.
· To keep progressing, you need to look at the 3 P’s - people, planet and profits - and keep finding opportunities to make improvements.
· He is glad to show TI’s competitors the RFAB building. If they choose to copy it, they will be copying where TI was five years ago.
· He believes in the “Prius effect”, meaning that if people can graphically see their consumption they are more aware and begin to change it, similar to watching the dashboard display on a Toyota Prius.
· Productivity initially applied to people being productive. We should also think of materials being productive and not wasted. Now people are abundant and materials are becoming scarce. In 1850, there were 1 billion on earth. Now there are 7 billion, and the earth hasn’t grown.
Geothermal - Greenland Energy Dynamics
Dan Dean, an energy engineer with Greenland Energy Dynamics discussed energy consumption issues mostly related to houses in the north Texas area. Sustainability with regard to housing includes the basic topics of materials, energy and behavior. Energy-related topics at a house include: insulation, higher efficient HVAC, windows, lighting, parasitic load, white roofs, building envelope, plumbing fixtures, solar thermal, solar photovoltaic, geothermal, and wind.
What issues would need to be focused on to design a house to near Net Zero energy consumption? Naturally, the goal would be to minimize the house’s electric demand or load, so that the amount of on-site electricity generation needed to equal it will be as low as possible. Even if not pursuing net zero, these are sound principles for housing design.
Orientation of the house on the site is important in the design phase. Passive solar design, which refers to using larger eaves and well-placed windows with regard to the pattern of sunshine, is part of this. In north Texas, cooling considerations outweigh heating. Providing shaded windows on the east, south and west is critical to controlling the HVAC load. Proper use of landscaping also affects the energy consumption of the house.
The thermal envelope of a house includes the slab, the walls, and the roof. In the north Texas area, the ground temperature averages about 68 degrees F. A concrete slab-on-grade tends to stay near this temperature, and since concrete has a high thermal mass, it does not quickly change temperatures. This means the slab is helpful in reducing the HVAC demand during air conditioning season, and is a part of the load in heating season.
The insulation and air infiltration through the walls and roof are also critical factors. Sprayed foam insulation performs much better than batt insulation because it fills each gap between the studs and sheathing, whereas batt insulation does not always fill all spaces, and may slide out of position over time. Even with the same theoretical R value (resistance to heat flow) the foam is about 7 times better than batts in terms of air infiltration. Radiant barrier fabrics, similar to foil sheets, are helpful also, but foam insulation is the best solution. However, a house can be sealed so tightly that it may become necessary to add an outside air supply to help purge indoor air contaminants.
The insulation and air infiltration through the walls and roof are also critical factors. Sprayed foam insulation performs much better than batt insulation because it fills each gap between the studs and sheathing, whereas batt insulation does not always fill all spaces, and may slide out of position over time. Even with the same theoretical R value (resistance to heat flow) the foam is about 7 times better than batts in terms of air infiltration. Radiant barrier fabrics, similar to foil sheets, are helpful also, but foam insulation is the best solution. However, a house can be sealed so tightly that it may become necessary to add an outside air supply to help purge indoor air contaminants.
For a typical house insulated with fiberglass batts, an HVAC design will require about 1 ton per 500 sq. ft. of space. For a foam- insulated house, the HVAC needed is about 1 ton per 700 to 1100 sq. ft. This is an example of integrated design that uses added insulation cost to reduce the HVAC installation cost.
The starting step in minimizing the electric demand is to create a “load schedule”, i.e. a table listing every electrical load. These include the HVAC system, which can be 60% to 70% of the total load if electric heat is used. Heat pumps are the same as conventional air conditioning, but they are also good for heating, at outside air temperatures down to 42 degrees. To heat the house at lower temperatures, electric heating must be used to supplement the heat pumps. From an energy standpoint, gas heat is better than electric heat.
Geothermal systems are much more efficient than an efficient split-system such as SEER 16. A geothermal system, at a house with an excellent thermal envelope, can save up to 90% on energy costs. Geothermal costs about $7000 to $11,000 per cooling ton to install, as compared to $3000 to $3500/ton for a conventional split system SEER 13. However, geothermal can earn the buyer a 30% federal income tax credit, reducing the cost premium.
Domestic water heating is another energy consumption issue. For a family of four, an electric water heater uses about $800 per year of electricity. A gas-fired water heater uses only about $250/year of gas.
Lights and appliances also should be listed in the table. Energy star appliances should be purchased. Ovens can be large electric loads for families that cook often. Efficient lighting such as fluorescent and LED should be used, along with occupancy sensors and dimmers.
On the energy production side of the equation, with the goal of getting a Net Zero house, electricity will need to be produced by either solar photovoltaics or wind turbines. Both of these options are expensive, which again is why the reduction of load is so important, to keep the capacity needed as low as possible. For example, the extra cost for geothermal HVAC reduces the electric bill at about half the cost of installing a photovoltaic system.
Axiom Sustainable Consulting
Michael Kawecki, owner of Axiom Sustainable Consulting, spoke to the class about LEED (Leadership in Energy and Environmental Design) and the USGBC (US Green Building Council). Axiom provides consulting on LEED projects and conducts LEED education sessions. Some basics about LEED to remember: LEED is the tool, developed by USGBC, to provide a scoring or rating system for green building. It is a voluntary program, although some cities are requiring it and/or putting its elements into their codes. LEED is a brand, like Energy Star ratings, that enables people to easily understand a building’s rating.
LEED was created by a wide range of parties involved in the built environment, to provide positive results for the triple bottom line (people, planet, profit); to define “green” building; to prevent green-washing; and to promote whole building integrated design. LEED does not certify products, because what matters is how the products get used in the building.
Why is it important to improve building construction? Because buildings stay in place for generations, so the building’s inefficiencies in energy and water consumption have annual effects for 40 or 50 years or more. Michael compared this to automobiles, which reach end of life and are replaced with new technology on a cycle of 7 to 10 years.
Michael reviewed the various LEED accreditations that exist now. These include LEED Green Associate, LEED Accredited Professional, and another pending level – LEED Fellow. The Green Associate is a newer accreditation level created in 2009, which is appropriate for most people that are involved in the design and construction industry and want certification that they understand LEED and its applications. Over time, he believes the AP designation will be mainly for the relatively few people that actually work with the LEED registrations and completion of the documentation for specific credits. As he pointed out, in the DFW area there are about 3000 AP’s and about 100 certified projects, so clearly there are many LEED AP’s that have not worked in detail on a specific project.
Mulch and Compost - Living Earth Technologies
The class visited Living Earth Technologies in Dallas. Our host was Paul Tomaso, currently the sales manager, formerly the LET general manager and founder of a predecessor company that was sold into LET in 1991. Paul holds degrees in chemistry and business, both of which are essential to this career. Living Earth makes and sells landscaping products, and is the largest composter and recycler of green waste in Texas, with numerous sites around the DFW Metroplex and the Houston area. LET’s typical customer is a local landscaping contractor, with a small portion of their business being the sale of bagged products to retailers such as grocery stores and homeowners. They also sell materials at the wholesale level to other yards that resell them. In addition, they stock some of the more common stone products, so that the landscape contractors can purchase those during the same trip to LET.
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| Crates to become fuelwood |
Their product manufacturing process takes place on-site. Raw materials that are trucked to the site include landscape maintenance debris like branches, leaves, grass clippings and leftover sod. Local food processing plants provide whole fruit and vegetables that did not meet their standards and the peelings or trimmed-off portions. Wood materials include used pallets and crates, and material from lumber mills such as bark and wood scraps.
From these materials, LET has many processes to grind, screen and mix to make a variety of mulch, compost, and soil blends. Some mulches are colored red, black, tan or brown. Pecan shell mulch is also a niche product they carry. From the street one may see the large piles of pallets and mulch and infer that pallets are made into mulch, but that is not the case. Pallet wood is not suitable for LET mulch, so it is made into pellets for “fuel wood” which is then taken to the lumber mills (on trucks that otherwise would be going to the mills empty to get more bark materials). The lumber mills use the fuel wood in drying kilns, instead of using natural gas.
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| Lettuce on the compost pile |
Mulches and compost are good for blending into the soil, to help a clay-based soil or a sandy soil. The mixture helps break up the clay soils so water can penetrate, and it helps sandy soils retain water that otherwise would quickly drain through. This enables plants to absorb nutrients.
Mulch is placed on top of soil. It helps conserve water by slowing the drying of the soil underneath. The mulch also acts to moderate the soil temperature by providing a layer between the soil and the ambient air temperature and sunshine. Weed growth is also deterred by mulch.
LET educates its customers on how to put nature in balance. Fungicides and fertilizer products knock soil chemistry out of balance, as Paul explained. He likened the use of strong, fast acting fertilizers to eating candy – it gives a fast boost but then wears off. Bugs attack plants that are unhealthy, so products generally are treating the symptoms. A better solution is to have healthy soil, with nutrients that are slowly released and slowly absorbed by the plants. The use of compost blended into the soil helps provide this. A good example of an end user for these products is the Texas Department of Transportation, which must establish vegetation on slopes after disturbing them during construction. The contractors and TXDOT value the healthy soil that can establish vegetation quickly, so soil erosion is minimized.In summary, we were very impressed by LET’s operations. They are keeping a very large amount of material out of the landfills, and instead using it to improve the environment by helping landscapes and improving topsoil. Their longevity of over 20 years, and numerous locations, proves that they are sustainable in both the business and environmental sense.
Urban Reserve
We visited this residential development in north Dallas and met with the developer, Diane Cheatham. This is a development with 50 lots, of which 26 have been sold and 16 have houses constructed so far. The development is quite different from the typical subdivision in Dallas.
The history of the project began in the 1960’s, when a previous developer sold lots based on drawings, but did not install any roads or utilities. The development was essentially abandoned and became overgrown, as well as becoming an illegal dumping site for concrete and asphalt. Many years later, another developer found the numerous land owners or their heirs, and assembled the tract for a redevelopment. Diane Cheatham purchased the property from that developer.
The concept for the development is to have unique houses with modern design. The unifying force is the landscaping. The street is a “skinny street” of 22 feet wide, rather than typical city standards. Low water landscaping that conforms to the plan is a requirement. Sustainable features on the development include decomposed granite driveways, retention ponds to capture irrigation water, and bio-swales that clean the runoff from the Urban Reserve and the upstream watershed. The property is easily accessible to the White Rock creek bike trail, and a DART station.
The homeowners at Urban Reserve are a diverse group. The commonalities according to Diane are a love for modern design and contemporary art, cooking, and for many of them bicycling on the trail. The owners are age diverse and the houses are diverse in price and size, from $300,000 to about $2,000,000.We toured Diane’s home, which is just being completed. She shared her opinions on sustainable features to use in home construction: an on-demand water heater instead of the conventional tank style; spray foam insulation instead of batts; and geothermal HVAC system. The site orientation is also important, and her site took advantage of many beautiful trees surrounding the house.
Plano Environmental Center
We visited this new building in Plano, although it has not opened yet so we made observations from the outside. The facility is intended to demonstrate sustainable technologies that can be implemented by homeowners and commercial builders in Plano. Green-building features incorporated in the project include
· Drip irrigation
· Bus stop at the property.
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| Solar water heater |
· Erosion control
· Bike rack
· Native trees, mulched areas. No turf.
· Decomposed granite pavement and parking areas, permeable.
· Covered parking with “carport” structure for shading, reduction of urban heat island.
· Photovoltaics on the carport structure.
· Rainwater collection from carport structure, into a water feature.
· Wooden roof deck exposed, presumed to be sustainably harvested wood.
· Daylighting, lots of windows and presumably low-e glass.
· Rainwater harvesting and storage tank from building roofing. Used for irrigation and perhaps for toilet flushing.
· Wind turbine for renewable energy generation on site.
· Efficient heat pump for HVAC
· Solar water heating
· Outdoor sink is made of recycled materials
· Recycling bins
· Mats at doors for indoor contaminant control
· Sealed concrete floors, with terrazzo from recycled glass.
· Art work from re-used aluminum cans
· Furniture from reclaimed wood.
Recycled Glass – Enviroglas Products:
The class visited the showroom and offices of Enviroglas Products in Plano, and met with Tim Whaley and Esteban Diaz, the founder and operations manager respectively. Enviroglas manufactures flat surface materials that can be used for countertops, flooring, shower enclosures, elevator cab walls, and many more applications. In general the products are used in place of terrazzo, granite or marble. The Enviroglas materials are made from recycled post-consumer glass, mixed with epoxy resin. Another recent addition is to use recycled porcelain from toilets with, or instead of, the glass.
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| Display of glass options |
Enviroglas products grew out of the practices of the terrazzo industry, and there are similarities and differences. Terrazzo uses a cement-based matrix with sand and stone aggregate, similar to concrete. Enviroglas is also a mixture but it has an epoxy resin base, and the sand and aggregate are instead pieces of broken glass. The glass has been tumbled to remove sharpest edges, and is sanitized. Both materials are cast as a wet mixture, cured, and then the surface is ground and polished to reveal the colored aggregates (stones or glass) and matrix. Terrazzo is generally cast in its place of use, whereas Enviroglas is cast in a shop and then transported as a loose element to be installed.
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| Two finished panels |
With all the possible colors that glass is made in, plus a wide range of possible colors for the epoxy matrix, the combinations of colors and effects are almost limitless. Hundreds of samples are available in the showroom, including standard mixes and providing the example for custom mixes. This is a fascinating company that is creating jobs and preventing useful materials from going to landfills by using recycled glass in a beautiful and creative new building product.
Rainwater Harvesting – Whiz-Q Stone
Matt Reed with Whiz-Q Stone spoke to our class about rainwater harvesting. Whiz-Q Stone sells materials to landscaping contractors and homeowners, including stone, pavers, landscape supplies, water garden supplies, and rainwater harvesting systems.
Rainwater harvesting is another application of the maxim to “think globally and act locally.” Ongoing water issues on a global or regional level include restrictions on irrigation due to constraints on the water distribution infrastructure; water wells going dry; groundwater contamination; and droughts affecting lake levels. Rainwater harvesting can:
· Reduce your dependence on the municipal water system or a well.
· Control runoff and urban flooding.
· Provide a source of water that has not been treated with chemicals.
· Reduce the embodied energy in pumping water from a lake to a water treatment plant, treating it to potable standards, and pumping it to your property.
In the future we will probably see tiered water rates, in which rates per gallon will be lower up to the amount of normal household use, but then escalate for additional water which would be for irrigation. Some cities now have rates that are the opposite, providing quantity discounts and not discouraging the use of potable water for irrigation.
Generally, a project to install a rainwater harvesting system will not have an attractive financial return in terms of reduced water bills only. However, many properties have significant investment in their landscaping. If a drought or other problem causes severe irrigation restrictions the plants can die, especially the shrubs and ornamental plants. Trees are generally hardy for a longer period of time, and turfs will go dormant in a drought but usually not die. So the economic value of a rainwater harvesting system is more like an insurance policy. Having some stored water on-site to irrigate landscaping is very valuable when other sources are not available.
Legislation has recently been enacted to encourage rainwater harvesting. For example, according to Mr. Reed, new commercial construction in Tucson must include rainwater harvesting. New construction larger than 2500 sq. ft. in Albuquerque must include rainwater harvesting.
In Texas, state law HB645 from 2003 prevents Homeowner’s Associations from prohibiting rainwater harvesting, composting, or efficient irrigation systems. That law helped promote rainwater harvesting for irrigation. In Texas all rainwater harvesting products are sales tax exempt.
The next evolution in rainwater usage is for indoor systems such as flushing toilets, and even as drinking water. This raises more concerns due to the risk of cross-contamination. Texas HB-3371 was passed in June 2011. It allows a structure to be connected to a public water supply system and have a rainwater harvesting system for indoor use, provided that the structure must have appropriate cross-connection safeguards; safe sanitary drinking water standards are met; and harvested rainwater does not come into communication with a public water supply system's drinking water at a location off of the property on which the rainwater harvesting system is located. A person who installs and maintains rainwater harvesting systems that are connected to a public water supply system and are used for potable purposes must be licensed by the Texas State Board of Plumbing Examiners as a master plumber or journeyman plumber and hold an endorsement issued by the board as a water supply protection specialist. This law is effective September 1, 2011 but the underlying rules are not yet completed.
Texas HB-3391 was also passed in June 2011. This law requires that on-site reclaimed system technologies, including rainwater harvesting, condensate collection, or cooling tower blow down, or a combination of those system technologies, for potable and non-potable indoor use and landscape watering be incorporated into the design and construction of each new state building with a roof measuring at least 10,000 square feet; and any other new state building for which the incorporation of such systems is feasible. For larger building, it requires rainwater harvesting system technology for potable and non-potable indoor use and landscape watering be incorporated into the design and construction of each new state building with a roof measuring at least 50,000 square feet that is located in an area of this state in which the average annual rainfall is at least 20 inches. In addition to these requirements for state buildings, the law states that “each municipality and county is encouraged to promote rainwater harvesting at residential, commercial, and industrial facilities through incentives such as the provision at a discount of rain barrels or rebates for water storage facilities”. In addition, each school district is encouraged to implement rainwater harvesting at facilities of the district.
Methods for rainwater harvesting have been used for centuries. Modern methods depend on the scale. The smallest method is a downspout that drains into a rain barrel. Moving up the scale, plastic tanks can be up to 2500 gallons and be underground. These generally cost about 50 cents/gallon. There are other types of above ground tanks, like the slim-line that is a rectangle with rounded ends. There are also steel tanks and concrete tanks for very large systems.
Another product instead of a tank is a matrix of blocks that have structural strength to support weight from above and from the sides. The blocks are mostly hollow, allowing water to fill the hollow spaces. These blocks are built inside a rubber membrane that is water tight. This type of system costs $3 to $5 per gallon, but it is nearly unlimited in shape and thickness, so it can fit many design situations that a tank could not.
Stormwater runoff can be captured from the roof, but also can be runoff from pavement or sitework. In urban areas, runoff from impervious surfaces like roofs and pavement during a heavy rain event is rapid and causes urban flooding. One solution for this is to construct a bioswale, also known as a rain garden if planted intensively. The bioswale concept is to collect runoff water and let it soak into the soil, which reduces urban flooding by reducing runoff rates.
Another solution is permeable pavers, which allow rainwater to drain through and between pavers into a collection system under the surface. Chicago has installed about 9 million sq. ft. of permeable pavers and drainage collection in the past five years, to reduce problems caused by heavy storm runoff into their combined sanitary and storm sewer system, which causes the whole system to overflow.
Rainwater harvesting contributes to LEED certification including credits for stormwater management, and additionally the tanks may have recycled content and/or may be from the local area.
Urban Farming – Green Phoenix Farms
Adam Cohen of Green Phoenix Farms spoke to the class about food in general and aquaponics in particular. Adam has two marine biology degrees and is a high school teacher. He recently started a business to raise vegetables and fish, and support others pursuing urban farming in the Dallas area. His larger goal is to improve local production of high quality food. He noted that the food that we purchase in grocery stores and restaurants has traveled about 1500 miles on the average. This uses a tremendous amount of energy just for transportation, and it has led to food with traits managed to make it capable of surviving the transportation and retailing process, sometimes at the expense of nutrition and flavor.
Aquaponics combines two unconventional methods of growing food. Hydroponics grows plants in growing beds without soil. The hydroponics systems are set indoors, provide great yields of food, but are expensive, and within a few weeks the fertilizing water solution has been depleted and needs to be replenished. The second method, aquaculture, refers to growing fish in controlled and contained bodies of water. This may be in a tank built for that purpose, or less intensively inside a cage in a larger lake or bay. In a closed system like the tanks, the water is circulated but it becomes laden with high nitrogen waste from the fish excrement.
Aquaponics involves using hydroponics and aquaculture simultaneously in a closed loop. The water from the fish tank contains nitrogen needed by the plants, so it is pumped to the plant tank and serves as a source of nutrients the plants need. The plants remove the nitrogen, leaving the water cleaner and it then can be returned to the fish tank. Fish are fed based on the species, but preferably the fish used in aquaponics can eat vegetables, such as some of those grown in the planting beds. This is very nearly a complete ecosystem created for this purpose.
A pioneer in aquaponics is Will Allen of Milwaukee, who operates a non-profit group called Gaining Power, Inc. which was highlighted in a YouTube video. This group started 24 years ago and now has about 300 urban farms in Milwaukee, generating about $5/sf in food production and providing jobs and healthy food to the local community. This is a clear example of achieving sustainability’s triple bottom line results.
Methods of aquaponics include (1) ebb and flow, in which the water level in the grow beds goes up and down, flooding and then draining so the roots can receive oxygen. (2) continuous flood, in which the oxygen level is kept high for the roots by using an aerator. (3) raft style, in which the plants are in containers that float.
Adam has a prototype aquaponics system constructed and recently started raising the fish and vegetables. Next on his agenda is to determine the marketing side of the business, finding customers for this food, especially the tilapia. Options include selling at a farmer’s market, selling to a niche restaurant, or targeting individuals such as diabetes patients that can manage their diabetes easier with higher quality food. Most farmers of this style have difficulty complying with the USDA certification for “organic” food, but they can truthfully label it as “raised to organic standards, not certified by USDA.”
Adam’s recommended readings related to urban farming include Urban Agriculture by David Tracy, and Mini Farming by Brett Markham.
Structural Insulated Panels - Korwall
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| Display model for typical house details |
The SIP panels consist of two layers of wafer board, more formally known as oriented strand board (OSB). Between the OSB skin layers, a core layer of closed cell foam, expanded polystyrene, is placed and pressure bonded. Panel thicknesses are 4 to 8 inches in most cases. The SIPs provide the insulation, so they are used for the building’s envelope. This can include not just the walls, but also the attic floor, the roof deck, or the first floor of a building with a crawl space under the floor. Interior walls and floors are constructed with conventional framing, and slab-on-grade is often the first floor as with normal construction.
Korwall starts the manufacturing process by building 8 ft. by 24 ft. panels. Customized adhesive is applied to the foam and the OSB boards and they are adhered. Then they are stacked and placed in a press and compressed for about ninety minutes to assure bonding and adhesion between the foam and wood. Curing time is provided per the manufacturer’s directions and documented, before removal and handling in the shop. After curing, each panel is custom cut per the shop drawings to the shapes, openings and edge treatments needed. Raceways for electrical rough-in are provided, and tongue-and-groove connections of adjoining panels are provided. Korwall’s crews do the field installation, typically in two days for a 2000 sq. ft. building. Connections are mechanically fastened and glued. Since all panels are pre-fabricated to correct dimensions, the corners and intersections have to be built square and true in the field, or else other panels will not align and fit properly. Once the SIP structure is installed, the exterior cladding and roofing can begin as with typical construction.
The two main benefits of SIP, compared to conventional stick framed construction with 2x4 or 2x6 studs and layers of batt insulation between studs, are strength and energy efficiency.
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| Press machine ensures adhesion of wood to foam |
The SIP strength advantage is in the monocoque or “structural skin” concept – the structural load is borne in the exterior skin rather than an internal frame that is covered with a skin. This concept is used in aircraft and car designs now. The SIP structures can carry twice the vertical load, and about five times the lateral or wind load, as a stick framed building. An 8 inch SIP can span 16 feet between supports. After many challenges in the early years, the SIP system is now broadly accepted in building codes.
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| Edge detail for joint with adjacent panel |
The energy efficiency advantage of SIP is two-fold. First, the theoretical R value of the foam insulation can exceed fiberglass batts. The R-value advantage is especially true in actual application, where the batts leave many air gaps and the studs interrupt the insulation for 1.5 of each 16 inches. The SIP insulation is continuous and without gaps. The lack of gaps is the second advantage – air infiltration is nearly eliminated through the SIP system with sealed joints between panels, while stick-framed walls allow considerable air infiltration. Korwall proves this in the field with air exchange tests, using negative pressure testing to show that at the same conditions a stick framed house allows 4 air exchanges per hour and a SIP house allows 0.5 air exchanges per hour.
The superior thermal envelope allows an HVAC system to be about half the capacity of a typical building, needing 1 ton per 1000 sq. ft. instead of 1 per 500 sq. ft. This saves initial construction cost, as well as reducing the energy consumption by the HVAC by half, for the life of the building. Korwall finds that the initial cost of a SIP building compared with stick-built is about a 5% premium. An analysis of the incremental cost to achieve a 50% HVAC energy savings would show that SIP construction is a more sustainable alternative to conventional construction.
The River Legacy Park is a 1300 acre site along the Trinity River in north Arlington. We toured the area near the Science Center on a brief nature walk with Anne Alderfer, a Texas naturalist. She explained the history of the River Legacy Foundation, a partnership including the city of Arlington that was established in 1988. The park was established in 1990, and the Science Center building was constructed in 1996 as an education and teaching facility. The building used many sustainable building systems, especially considering its design and construction in the pre-LEED era. 
Recycling programs in the city generally reduce the volume of waste that must go into the landfill as a last resort. However, the McCommas Bluff operation also includes some recycling, such as trees and brush which are shredded into mulch, and asphalt or concrete pavement materials which are crushed and used on-site for roads. These materials are unloaded and processed in a separate area from the active cells. The landfill also uses crushed glass in layers, to improve permeability for internal drainage inside the cells.
While obviously a smelly and messy process at the open area where dumpsters and trucks are being emptied, McCommas Bluff protects the surrounding area and the groundwater. The entire 1000 acre landfill footprint itself is surrounded by a levy system and is part of a 2000 acre property. The landfill cells are lined with an engineered combination of clay layers and rubber liner materials. The McCommas Bluff cells started in 1975 at elevation of 320 feet, and the tallest cells now are at 450 and 490 feet. The facility is permitted to build up to elevation 550. Not all of the permitted cell footprints have been started yet. Projections are that the whole landfill footprint will reach its maximum height in about 2056.
Since the 1990’s the landfill gas produced within the landfill by decomposition of materials has been captured, processed and used. Horizontal systems of gas collection piping are installed at 40 foot vertical intervals. These collect the landfill gas at a central facility that processes the gas. Landfill gas is about half carbon dioxide and half methane, with small amounts of other elements. The landfill gas is processed and the methane (natural gas) added to the local natural gas utility system is enough to heat about 11% of the homes in Dallas, according to Mr. Picha.
Dallas Clean Energy (DCE) is the contractor operating the landfill gas process, and the McCommas landfill gas operation currently generates about $2 million in royalties annually for the City of Dallas. DCE estimates that pipeline quality biomethane gas will continue to be produced for approximately 30 years after the landfill closes. The plant is currently capable of processing 9.4 million cubic feet a day of landfill gas into approximately 36,000 gasoline gallon equivalents of pipeline quality biomethane. DCE plans to increase this capacity to approximately 14.9 million cubic feet a day and make further improvements that should enable the production of approximately 60,000 gasoline gallon equivalents a day of pipeline quality biomethane. DCE equates methane to gallon equivalents because their main focus is on using natural gas in place of diesel or gasoline as a transportation fuel.
On behalf of all the class members, thank you to the many people that gave their time and shared their knowledge to help us learn about sustainable organizations in north Texas.
"All economic activity is dependent upon the environment and its underlying resource base of forests, water, air, soil, and minerals. When the environment is finally forced to file for bankruptcy because its resource base has been polluted, degraded, dissipated, and irretrievably compromised, the economy goes into bankruptcy with it."—Gaylord Nelson—US Senator and Founder of Earth Day
River Legacy Living Science Center
The River Legacy Park is a 1300 acre site along the Trinity River in north Arlington. We toured the area near the Science Center on a brief nature walk with Anne Alderfer, a Texas naturalist. She explained the history of the River Legacy Foundation, a partnership including the city of Arlington that was established in 1988. The park was established in 1990, and the Science Center building was constructed in 1996 as an education and teaching facility. The building used many sustainable building systems, especially considering its design and construction in the pre-LEED era. The most striking and unique feature of the building is the use of three trees to serve as structural columns supporting the building’s roof framing. Recycled materials were used inside, including tiles that were made from car windshield glass. Natural light enters at the ridge line of the roof, and the ridge line is curved to provide a more organic or natural shape to the building footprint. The access drive and parking areas were laid out to save many of the large old trees in the area. Decomposed granite and porous pavement with pavers were used in the parking areas rather than concrete pavement.
After touring the building, we took a nature walk and observed many native plants and trees in the bottomland near the river, suitable for including in a sustainable landscape. These included passion vine, Virginia wild rye, inland sea oats, and others. We also noted the damage to some trees from the trail construction, evidence of sapsucker woodpeckers on a cedar elm tree, and annoying plants such as poison ivy and ragweed. The new word of the day for me was “crepuscular”, meaning an animal or insect that is most active at the twilight times of dusk and dawn. Signs of the heat and drought were evident throughout the park. The most important sustainability point of the walk was that with education programs such as this, more people can learn to appreciate and help preserve wildlife and native landscaping. When the cooler weather returns, we should return too and learn more.
McCommas Bluff Landfill
We visited the largest landfill in Texas, the McCommas Bluff Landfill which is owned and operated by the City of Dallas. Far from being a “dump”, a large landfill is a professionally managed public works asset involving chemical processes and engineering, business aspects, and extensive regulation. Environmental coordinators Jonathan Picha and Dayna Cowley hosted a briefing in the city’s Eco Park building, followed by a tour of the landfill.
McCommas Bluff receives waste from Dallas’ residential garbage pick-up system, citizens, contractors, and commercial dumpsters, taking in 7,000 tons of garbage a day or almost 2 million tons a year. Each user pays fees as appropriate. The landfill fees are a net positive source of revenue to the City each year, helping to support all the other services the City provides.
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| Mr. Jon Picha explains landfill operations |
Groundwater-monitoring wells surround the landfill footprint. Soil cover is placed on the top of the fresh garbage daily, to contain the blowing trash and the landfill gas that is produced by decomposing garbage. Community service workers pick up loose trash items such as plastic bags that have blown out of the cell area, to prevent them from blowing offsite.
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| Landfill gas collection |
Since the 1990’s the landfill gas produced within the landfill by decomposition of materials has been captured, processed and used. Horizontal systems of gas collection piping are installed at 40 foot vertical intervals. These collect the landfill gas at a central facility that processes the gas. Landfill gas is about half carbon dioxide and half methane, with small amounts of other elements. The landfill gas is processed and the methane (natural gas) added to the local natural gas utility system is enough to heat about 11% of the homes in Dallas, according to Mr. Picha.
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| Leachate collection system |
Conventional landfills are “dry entombment” systems in which the garbage is kept dry to reduce problems from the leachate liquids and methane gas. However, the benefits of a “wet” landfill have been proven. Dallas recently added infrastructure for Enhanced Leachate Recirculation (ELR). This system is the first of its kind in Texas to use leachate recirculation at the higher “enhanced” rates. ELR includes addition of controlled liquids such as stormwater into the landfill through pipe networks (also at 40 foot vertical intervals, 20 feet offset from the gas piping), to speed the chemical reactions of the decomposition process. The water increases the production of landfill gas and, more importantly, speeds the consolidation of the landfill materials. The consolidation of the materials lowers the elevation of the top of the cells, so that over time, additional waste can be added before the landfill reaches its maximum permitted height. Since all waste haulers pay tipping fees, the additional capacity to accept waste means additional revenue to the city, obtained for a modest cost.
The additional water from the ELR process results in additional leachate drainage into the bottom of the cells. This leachate liquid can vary from relatively harmless to very toxic, depending on the wastes in the landfill. Leachate is collected and treated at a nearby but off-site facility.
Although landfills are a necessary evil, the McCommas Bluff landfill is serving the citizens of Dallas by obtaining a positive economic benefit from the tipping fees and the landfill gas royalties, while protecting the surrounding air and water from environmental damage. The ongoing efforts to increase recycling and composting to divert materials from landfills can reduce the volume of the landfill used by garbage, thus extending the life and the economic benefits further into the future.
Insulated Concrete Forms – Alan Hoffmann
Alan Hofmann spoke to the class about home building and insulated concrete forms (ICF). He has been a homebuilder for seventeen years, and has only built green and energy efficient houses. He built the first home in Dallas to be LEED and LEED Platinum rated. He stressed the importance of focusing on the building envelope and the HVAC system, not “green gizmos.” We are in a region that has wind storms frequently and tornadoes occasionally also, so a strong structure is advantageous.
Construction that reduces the amount of air exchange through the envelope is critical to achieving energy efficiency. The typical sticks and bricks house has enough air leakage to equate to having one door open. This type of house has a lifespan of about 70 years, at which time it is beyond maintaining and is demolished.
Thermal mass is also useful in controlling interior temperatures, and energy consumption. On Alan’s travels to Spain he saw houses that are hundreds of years old, with minimal or no HVAC in a climate similar to Austin, Texas. The difference is that these houses have three foot thick walls that stay near a constant temperature at all times – quick swings in air temperature do not change the temperature of a three foot thick masonry wall, so it can absorb heat and moderate the air temperature inside the house.
After years of building and working with these concepts, John’s preferred building system is insulated concrete forms for the exterior walls. These are foam blocks with metal ties across a hollow center. The blocks are set in place in stacks, and then the hollow center is filled with concrete. The result is a concrete wall that has thermal mass, unlike a typical balloon frame wall. And it has insulation value from the foam. Usually his houses have wood framed roof structures, so the overall system is a hybrid. Often the roof deck will be sprayed with open cell foam to enclose the attic inside the thermal envelope. The ICF structure is much stronger than a conventional house in wind loadings, is more tornado resistant, and is not susceptible to termites due to the absence of wood. Costs for the style of house that Alan builds with ICF generally are 6% to 8% higher than sticks and bricks with fiberglass batt insulation, he said.
As for the energy efficiency, a recently competed house in east Dallas was 2700 sq. ft. and the electric bill averages $90 to $100 per month. As opposed to the equivalent of an open door for a typical house, this house has air exchange area the size of a notebook computer. At one of his projects in Corsicana, the air conditioning capacity for a 2656 sq. ft. house only needed to be 2.25 tons compared to 4.5 tons for a typical house.
In housing, Home Energy Rating System (HERS) scores are used to quantify energy efficiency. According to www.resnet.us, the HERS Index is a scoring system established by the Residential Energy Services Network (RESNET) in which a home built to the specifications of the HERS Reference Home (based on the 2006 International Energy Conservation Code) scores a HERS Index of 100, while a net zero energy home scores a HERS Index of 0. The lower a home's HERS Index, the more energy efficient it is in comparison to the HERS Reference Home.Each 1-point decrease in the HERS Index corresponds to a 1% reduction in energy consumption compared to the HERS Reference Home. Thus a home with a HERS Index of 85 is 15% more energy efficient than the HERS Reference Home and a home with a HERS Index of 80 is 20% more energy efficient.
Public Interest Design – BC Workshop
Brent Brown and Benje Feehan spoke to the class about BC Workshop, their architectural and planning firm. BCW is not a normal architectural firm; they are a 501c3 not- for- profit organization that does architecture and planning. The firm includes paid employees and volunteers from AmeriCorps VISTA, a national service program of the US government. VISTA members commit to serve full-time for a year at a nonprofit organization or local government agency, working to fight illiteracy, improve health services, create businesses, strengthen community groups, and much more. BC Workshop has a total staff of 18 people, and it was started in 2005.
BC Workshop has two sides to their practice: direct architectural design for a fee, usually working for non-profit organizations; and Initiatives. The Initiatives are projects that they self-generate in response to a need in the community. Another way to describe their practice is that some of the work is on products (homes, buildings, gardens) and some is on planning (city planning or neighborhood planning.)
They believe it is the designer’s ethical duty to look at the social, environmental, and economic design aspects. Of the three elements of sustainability, they go most strongly for the social equity leg because it gets less attention than economics and environmental aspects. This approach has a few different names in the architectural field including “community design”, “humanitarian design” and “public interest design.”
Brent said that architecture should be about people. There should be more to it than complying with the life safety and building codes. Even the stakeholders in a project that are not the contractual paying client should have a voice in a planning or design process. They feel that a good design approach would be to say to the stakeholders or users “we need you to help us plan or design this for you” instead of “we are professionals and we know what you need.”
The BC Workshop has been working on a project called Congo Street in Dallas. This is neighborhood built in the 1930’s and basically ignored in recent years by the city as other nearby streets were upgraded. The average house is 625 sq. ft., and the street right of way is 19 feet wide. BC Workshop learned about the need for an upgrade project at Congo Street, and met with the residents many times to build trust and find out what they would like to see happen to their block. They got the residents informed and involved in selecting the landscaping for the street redevelopment. A landscape architecture firm volunteered their design services also, after initially volunteering just to provide unskilled labor as a community service day. The resulting street will have permeable pavement, bioswales, and landscaping that will be manageable for the residents. Homes are being renovated during the project as well.
Aquaponics and Papercrete – SynergyFish
Dave Pennington of SynergyFish spoke to the class about aquaponics. He explained that in the 1500’s the Aztecs used a unique system of farming in Tenochtitlan that today would be considered aquaponics. The Aztecs built man-made islands in a lake in rectangular shapes, with a grid of canals in between. Many of the islands were used for farming and were highly productive due to the fertile soil from the marsh bottom that was used to build the islands. The ability to have a dependable and local food source enabled the growth of the city. The aquaponics system solved the problem of managing waste that the Europeans had not solved, and the population in 1519 was estimated to be about 200,000 to 400,000 people when the Spaniards discovered it in 1519.
Today, we have some global problems that can be addressed with aquaponics. These include overfishing of the oceans; insufficient amounts of healthy food; water shortages; inefficient use of energy; and pollution from industrial agriculture. Overfishing is eliminating fish, and in turn when the fish supply is reduced, people seeking more protein will find it in animals on land. “Cheap” meat as mass produced in large scale farming is causing many health problems in our population which are expensive for the health care system to manage. About 85% of our fresh water is sprayed on the ground in agriculture, he said, and much of that becomes contaminated with fertilizer and pesticides.
Aquaponics consumes about 10% of the water that normal agriculture does, because the water is re-used repeatedly. It uses water sources that would be treated as “waste” otherwise. Efficient local food production decreases the embodied energy in food, compared to transporting it from far away. A significant amount of locally grown fish would reduce the pressure on the ocean’s fish population.
A leading source of training for aquaponics is the University of Virgin Islands. Australia has a lot of aquaponics due in part to their extended drought conditions. Epcot center at Disney World also practices aquaponics. Another established aquaponics business is AquaRanch Industries in Illinois, which raises tilapia, mint, lettuce and basil as well as selling aquaponics systems.
Dave believes that tilapia makes the best choice for an aquaponics fish species. Tilapia can eat vegetables while most of the fish we eat are predators, i.e. they eat other fish. The one pound of predator fish that we eat has eaten about 4 pounds of smaller fish. So, growing 1 pound of tilapia with aquaponics is saving 5 pounds of fish in the wild. Tilapia has a mild flavor, so it is up to the chefs and cooks to prepare it in a tasty way.
Small aquaponics systems can be 100 gallons with a 32 sq. ft. garden space, and get larger from there. At that size, it seems feasible for a restaurant to have its own system and grow their fish right at the restaurant.
A related interest for Dave is the construction of dome structures from “papercrete”. These could be used in aquaponics or for small buildings like cabins. The papercrete material is a mixture made from cement, water, and paper and foam beads. The material has 60 to 80% paper and foam, has some insulating value which has not yet been specifically determined, and would be totally recyclable at the end of its life.
The dome building method is preferred because of the inherent strength and wind resistance of a dome structure. The dome shape is constructed by building a cloth “balloon” made to the shape of the interior of the dome and inflated with air pressure. When inflated, the fabric serves as a form and the papercrete can either be spray applied like shotcrete, or prefabbed blocks can be cast, and then the blocks can be laid in place and mortared with papercrete. The latter method is suited for small scale or community volunteer projects.
Sustainable Structures of Texas – Montgomery Farm
Sustainable Structures of Texas (SSOT) is a construction contractor and design-builder. Lee Hall is the founder of SSOT, and he led the class through the Montgomery Farm development in Allen. SSOT was formed in 2007 to perform construction work at Montgomery Farm including commercial and residential projects.
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| Mockup of advanced framing techniques |
The first stop was a custom home on Monica Rd, the first LEED Gold home in Collin County, which SSOT constructed. The house includes “advanced framing techniques” with 2x6 studs at 24 inches on center and R19 insulation in the cavities, an R5 sheathing board on the exterior of the studs, and metal diagonal strapping with hurricane tie-downs for structural strength. The advanced framing techniques are cited on the National Association of Home Builders website for reducing the total amount of framing lumber due to optimization and for increasing the energy efficiency of the envelope. The wall assembly sums to R24, and with the extra attention paid to sealing gaps and using spray foam insulation where needed, the house is very air-tight compared to conventional stick framing, but without using systems that are unfamiliar to local building trades. The house achieved an excellent HERS rating of 49, due to the air-tight construction and sustainable features such as LED lighting and 16 SEER air conditioning.
Another sustainable feature is the use of rainwater collection from the building roof and the patio cover. The water is routed to a bio-swale or rain garden in the back yard, which detains runoff and allows more water to soak into the soil.
We stopped briefly at the site of Angel Farm office building, a project that commenced in 2007 and 2008 with extensive excavation including provisions for about one million gallons of stormwater storage under the building. However, construction was halted as the commercial real estate market plunged in 2008, and the site remains, holding water in the excavated area and waiting for a market recovery.
We also visited the site of a 20 acre development area at the Alma/Bethany intersection which is included as a pilot project in the LEED Neighborhood Development rating system. This will be a mixed use development with some retail, townhouses and detached houses.
Finally, we met in the Montgomery Farm offices which are in the former farm house on site. Mr. Hall discussed the LEED for Neighborhood Development program which was rolled out in 2010. He serves as the USGBC advocate for LEED ND in north Texas. LEED ND looks beyond individual building ratings, and considers a whole development in three major categories: smart growth, new urbanism, and green building. LEED NC certification is a stepped process including a conditional letter of approval based on the site plans; a certificate for a “Pre Certified LEED ND Plan” at build-out of 0% to 75%; and final certification at full build out.
LEED NC rewards features including: urban infill, walkable streets, connectivity, bike friendliness, mixed use developments, and the neighborhood patterns in design that are part of New Urbanism.
Challenges to this style of development include accommodating cars, garbage trucks and fire trucks; balancing higher density (dwellings per acre) requirements with some citizen opposition to those density levels; and appraisal procedures that do not always capture the value of energy efficient buildings that have lower operating costs.
Pat Lobb Toyota of McKinney
We visited with Robert Castle, Fleet Manager at Pat Lobb Toyota of McKinney. This was the first LEED Certified Car Dealership in the US. The management at this dealership sees sustainability and business as being totally aligned. They stated that the premium in construction cost for the sustainable aspect of the project was 7%, with a simple payback of three years. The project also earned Pat Lobb Toyota a lot of favorable publicity nation-wide.
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| Display boards provide information on green features |
Some of the green-building features include: high recycled content in the building materials used such as tiles and aluminum panels, a white roof which reflects sunlight, water cooled air conditioning system, high reflectance in the concrete pavement due to inclusion of fly ash in the mix, growth of vines on the sides of the building to provide shade, no volatile organic compounds in the paints, captured rainwater and condensate, efficient irrigation system, heating system that is fueled with waste oil from oil changes, and an ionization system that cleans the recycled water from the car washing bays.
Toyota at the corporate level values quality, durability and waste elimination. This building is very consistent with those values. In addition, the dealership has a very high employee retention rate in part because the workplace is desirable, so the people, planet and profits are all being taken care of with this project.
Pat Lobb, the dealership owner, spoke with the group and advised us on making the case for sustainability: “approach everything from a return on investment standpoint first, and you will never have to apologize to anybody”. He also said in response to a question about solar photovoltaics that as a matter of philosophy, they will not accept government grants or tax credits to subsidize a feature, because that is not sustainable. It was clear from his remarks that he was thoroughly involved in the decision making during the project, and continues to look for more improvements that are feasible and economically justified.
McKinney Green Building
We visited the McKinney Green Building, which is the first LEED Platinum-rated core and shell office building in the US. The building has numerous features including light shelves which reflect light into the building while shading the windows below, pervious pavement with pavers and sub-base that drain into underground gravel beds for storage; solar photovoltaic panels on the roof; under-floor air distribution system in all tenant spaces; geothermal wells for the HVAC system; and waterless urinals.
McKinney Green Gardens at Gabe Nesbitt Park
Inside the Gabe Nesbitt Park, the City of McKinney and the Texas AgriLife Research and Extension Center have built Demonstration Gardens. The purpose is to provide examples of water-efficient plants and native plants that are suitable for landscapes in McKinney. The gardens are divided into several areas with varieties of turf, shrubs and ornamental grasses. Decomposed granite is also used throughout. Many signs are posted to identify the species for the citizens. Considering the severe temperatures and lack of rain this summer, the plants are in good condition and are proving their ability to cope.
On behalf of all the class members, thank you to the many people that gave their time and shared their knowledge to help us learn about sustainable organizations in north Texas.
"All economic activity is dependent upon the environment and its underlying resource base of forests, water, air, soil, and minerals. When the environment is finally forced to file for bankruptcy because its resource base has been polluted, degraded, dissipated, and irretrievably compromised, the economy goes into bankruptcy with it."—Gaylord Nelson—US Senator and Founder of Earth Day
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