Tag Archives: Sustainability

Car Dealerships and LEDs: Implement Sustainability and Reduce Costs

All photos courtesy Optec LED Lighting

All photos courtesy Optec LED Lighting

by Jeff Gatzow

When car dealerships try to outshine each other through the use of bright light on their lots, much of the illumination is wasted off the lots’ parameters. While these lights serve a dual purpose of attracting potential customers and as a 24/7 security system, they also devour energy.

There are more than 17,000 automotive dealerships in North America. On average, they use up to 18 percent more energy than a typical commercial building annually. Consuming $1.9 billion dollars in energy costs a year, lighting can represent up to 45 percent of those costs as dealerships emphasize marketing their inventory and differentiating their facility from the competition. This amount can add up to thousands of dollars in annual energy costs for a typical dealership.1

Optimized illumination performance enhances the appearance of vehicles.

Optimized illumination performance enhances the appearance of vehicles.

Before#1_Toyota-1

 

 

 

 

 

 

 

 

Saving opportunities
Reducing energy costs is a major consideration for dealerships, which is their third-highest overhead expenditure.2 In 2006, the National Automobile Dealers Association (NADA) formally endorsed the Environmental Protection Agency’s (EPA) EnergyStar Challenge by asking its 20,000 members to reduce annual energy use by 10 percent or more. EPA estimates if auto dealers cut their consumption by this amount, nearly $193 million would be saved and more than one million tons of greenhouse gas (GHG) emissions would be prevented.3

In 2007, NADA and Energy Star launched a joint Energy Stewardship Initiative to help auto dealers improve the energy efficiency of their facilities and operations. The initiative provides data, tools, and other strategies for dealers to implement improved energy practices and technologies at their facilities. Since this launched, more than 800 dealerships have improved the efficiency of their facilities by reducing energy use by 10 percent or more annually.4

Automakers have been climbing aboard the ‘green’ bandwagon for years, with low-emission, high-mileage vehicles that appeal not only to customers looking to save fuel, but also to buyers eager to participate in what is perceived to be an environmental solution. Now, dealerships are following suit. However, dealerships with large parking lots, numerous buildings, and 24-hour demand for light have energy challenges.

LED technology
One potential technology for car dealerships is the light-emitting diode. Light-emitting diodes (LEDs) differ from traditional light sources in the way they produce illumination. In an incandescent lamp, a tungsten filament is heated by electric current until it glows or emits light. In a fluorescent lamp, an electric arc excites mercury atoms, which emit ultraviolet (UV) radiation. After striking the phosphor coating on the inside of glass tubes, the UV radiation is converted and emitted as visible light.

An LED, in contrast, is a semiconductor diode. It consists of a chip of semiconducting material treated to create a structure called a positive-negative (p-n) junction. When connected to a power source, current flows from the p-side (i.e. anode) to the n-side (i.e. cathode), but not in the reverse direction. Charge-carriers (electrons and electron holes) flow into the junction from electrodes. When an electron meets a hole, it falls into a lower energy level, and releases energy in the form of a photon (light).

All light sources convert electric power into radiant energy (i.e. visible and invisible light) and heat in various proportions. Incandescent lamps emit primarily infrared (IR), with a small amount of visible light and heat. Fluorescent and metal halide sources convert a higher proportion of the energy into visible light, but also emit IR, UV, and heat.

As a relatively new technology, LED luminaires currently cost more to purchase than traditional fixtures lamped with high-pressure sodium or metal halide light sources. However, the reduction in relamping expense and increase in energy savings typically lower overall lifecycle cost by about 50 percent.

According to information from the report “Unlocking Energy Efficiency in the U.S. Economy,” a comprehensive lighting retrofit eliminates overall energy costs by up to 75 percent, with the upfront costs recaptured in less than three years.5

Exterior LED luminaire technology has turned the corner from specialty applications to general illumination. Powering this important change is a combination of performance improvements in the core technologies, introduction of a wide range of well-designed products, and continued cost improvements.

The design of LED luminaires is a new world compared to traditional light fixture design. Optical, thermal, and power supply characteristics have a drastic effect on the longevity, performance, and affordability of light fixtures using LEDs.

The generation of luminaires using LEDs dictates the need to harness and manage as much of the light energy as possible. Misdirected illumination usually means wasted light, requiring the need to engineer even more initial light to reach target deliverable light levels. Of course, generating a greater amount of light means higher costs and more heat generation, and if poorly managed, can reduce fixture life.

To minimize the number of LEDs used its important to employ high-performance engineered optics, which allow for more efficiently captured and managed light. The result is superior light distribution with less waste. LED luminaires using high-quality optics are far better at improving light uniformity than any other technology available today.

The prognosis is positive. LED luminaires’ efficacy continues its overall upward progression, doubling in the past two years among tested solid state lighting fixtures. Further, color quality is also steadily improving, making exterior LED luminaires a viable alternative to traditional sources.

The bottom line for LED lighting systems is they have the potential to save a substantial amount of energy costs for lighting over the lifetime of a project. In addition to the energy savings, the long life of LEDs in well-designed systems will result in significant reductions in both labor and material costs for maintenance.

These photos show Gary Force Toyota’s lot illuminated with traditional metal halide fi xtures. A total of 63 of the 1000- W fi xtures were replaced with 240-W light-emitting diode (LED) luminaries for dramatic energy savings.

These photos show Gary Force Toyota’s lot illuminated with traditional metal halide fixtures. A total of 63 of the 1000- W fixtures were replaced with 240-W light-emitting diode (LED) luminaries for dramatic energy savings.

After#1_Toyota

 

 

 

 

 

 

 

 

 

National dealership sustainability initiatives
In 2010, Ford introduced its Go Green Dealer Sustainability Program at three of its dealerships; the auto-maker is now planning to make changes at all 3500 dealerships nationwide. The initial three facilities—one in Florida, one in New York, and one in Nevada—implemented a comprehensive assessment and evaluation of their impacts, primarily from an energy consumption standpoint. Lighting was a key element of the retrofits, aimed at addressing both the quantity and the quality of the onsite lights.6

Ford continues to expand Go Green, as participants can now receive an energy assessment through the Ford Electric Vehicle (EV) Program. The goal of the Go Green program is simple: collaborate with dealers to implement cost-effective ways to improve the energy efficiency of their facilities. Going forward, it will continue to be a key component of Ford’s Dealer Electric Vehicle Program as the company expands its model offerings. As part of the certification process to sell EVs, Ford EV dealers undergo an energy assessment to identify opportunities to reduce their overall carbon footprint and lower their energy expenses.7

Additionally, in 2013 the Go Green energy assessment became an integral component of the U.S. Ford facility renovation program. The company’s goal to renovate more than 700 U.S. Ford Motor Company branded facilities during the next few years presented a tremendous opportunity for green technology implementation within the dealer network.

Ford is not the only car company with sustainable dealership initiatives. Nissan Green Shop Activities include various environmental efforts that take place at Nissan Motor dealerships across the globe, including reducing waste, recycling, and energy saving endeavors. The program was introduced in April 2000 as an environmental management system for all Nissan dealerships.

Something that dealerships in these programs implemented is energy-efficient lighting, which provides one of the quickest paybacks.

Funding assistance
Recently, many dealers moved quickly to take advantage of the Internal Revenue Service (IRS) Section 179D tax incentive, which expired last year. This is the section of the tax code that provided a benefit for businesses, architects, engineers, and contractors when they built or renovated an energy-efficient building.8

If the building project did not qualify for the maximum Energy Policy Act (EPAct) $1.80 per square foot immediate tax deduction, there were tax deductions of up to $0.60 per square foot for each of the major building subsystems—lighting, heating, ventilation, and air-conditioning, and the building envelope.9

Utility companies around the country are encouraging these efforts by offering energy-efficient lighting upgrade and replacement rebates, some of which cover up to 50 percent of installation costs for retrofits. Most utility rebate programs are offered on a first-come, first-served basis until funding is exhausted or the program is discontinued, so it is important for customers to get applications in early.

There are two types of utility rebate programs:

  • prescriptive rebates offer a fixed, predetermined dollar amount for each fixture replaced; and
  • custom rebates are based on the total energy savings of a specific lighting retrofit.

Custom rebate programs offer payments for both actual energy savings (kilowatts saved per hour) of upgrading to more efficient lighting technologies and reductions in peak demand (kilowatts) achieved in the first year after implementation.

Prescriptive rebates, however, do not account for the energy savings gained by reducing the number of fixtures through a redesign. Utilities in almost every state offer some rebates for light emitting diode systems. Details on these programs are aggregated in the federal DSIRE database and individual utility sites.10

The photos to the left show Gary Force Toyota’s lot after the replacement. The installation of LED luminaires enhances the appearance of the vehicles. The new exterior lighting allows the dealership to decrease operating expenses.

This photo shows Gary Force Toyota’s lot after the replacement. The installation of LED luminaires enhances the appearance of the vehicles. The new exterior lighting allows the dealership to decrease operating expenses.

Energy-effi cient LED area lights transform Gary Force Toyota’s parking lot and are virtually maintenance-free.

Energy-efficient LED area lights transform Gary Force Toyota’s parking lot and are virtually maintenance-free.

 

 

 

 

 

 

 

 

 

LEDs in action
Established in 1973, family-owned Gary Force Toyota is part of three award-winning auto dealerships. Based in Bowling Green, Kentucky, the dealership is committed to incorporating sustainable products into the facilities.

Exterior luminaires
As a long-established business, the owners and management team knew they could make a strong environmental statement while also attracting customers. Car dealership lots use a tremendous amount of energy and install many light fixtures to illuminate the cars outside at night.

Gary Force Toyota sits on a 0.8-ha (2-acre) lot with a 210-car inventory, and an 1858-m2 (20,000-sf) showroom and repair shop. The dealership recently replaced 63 of the old 1000-W metal halide fixtures in the exterior lot with the same number of 240W LED luminaires. The dealership also replaced six 250W metal halide wall packs with six 60W LED wall packs.

The impetus for the LED retrofit was the dramatic energy savings. Previously, the dealership was spending almost $30,000 annually on utility costs, however, with the new luminaires, their energy costs will be reduced to approximately $6620. Additionally, every three months, about

12 of the metal halide fixtures needed maintenance, costing $26,400 in maintenance over five years. Now, the new LED luminaires are virtually maintenance free with a five-year warranty.

After seeing the product, learning about the energy savings—greater than 70 percent over the metal halide—and determining the dealership would have just a two year return on investment (ROI) on the LED lights, it was an easy decision. The Tennessee Valley Authority also provided an incentive of $21,700 for upgrading the fixtures to LED.

The LED luminaires provide consistent light levels, reduce hazardous waste disposal, and provide dramatically more efficient light distribution than the metal halide fixtures.

“The new exterior LED lighting allows us to drive down operating expenses, present our cars in the best light, and contribute to the greening of our community,” said Dave Stumbo, owner and vice president/general manager.

Both employees and customers have noticed the bright, white lights and have commented about how much easier it is to see the cars, anywhere in the lot.

“We installed the LED luminaires because they pay back in so many ways,” continued Stumbo. “Additionally, we are so impressed with how well these LED luminaires are performing at Gary Force Toyota we upgraded the exterior lighting at our Acura pre-owned dealership in Franklin, Tennessee.”

Additionally, the lights did not disturb surrounding businesses or residential areas. Many LED fixtures are designed for full cut-off. This means little to no light is emitted above the horizontal plain, therefore minimizing light pollution. To curtail light trespass (i.e. light extending beyond property lines and other boundaries) it is important to use fixtures with the right distribution patterns for the required area.

Conclusion
There are numerous factors contributing to dealerships’ sustainability efforts, such as manufacturers’ national initiatives, consumers’ increased concerns about environmental issues.

An environmentally conscious car dealership seems to be contradictory term. However, the bottom line is that by living and working sustainably dealerships can reduce energy costs, increase their brand/dealership’s recognition, and attract more customers.

Renovations such as LED lighting retrofits or the installation of light-emitting diode luminaires uring new construction are an excellent way for car dealerships to begin achieving their sustainability objectives.

Notes
1 For more, visit www.energystar.gov/buildings/sites/default/uploads/tools/A_Dealer_Guide_to_ENERGY_STAR.pdf. (back to top)
2 See E Source Customer Direct’s “Managing Energy Costs in Auto Dealerships” at www.sba.gov/content/energy-efficiency-auto-dealers. (back to top)
3 See note 1. (back to top)
4 Visit Auto Remarketing’s “NADA Encourages Dealers to take Survey on Energy Use,” article at www.autoremarketing.com/trends/nada-wants-help-dealerships-%E2%80%98go-green%E2%80%99-how-energy-efficiency-will-improve-your-bottom-line. (back to top)
5 For more, see “Unlocking Energy Efficiency in the U.S. Economy” at www.greenbuildinglawblog.com/uploads/file/mckinseyUS_energy_efficiency_full_report.pdf. (back to top)
6 For more, see Matthew Wheeland’s “For Expands Efficiency Efforts to its Dealers’ Lots,” at www.greenbiz.com. (back to top)
7 For more, visit corporate.ford.com/microsites/sustainability-report-2012-13/people-dealers. (back to top)
8 For more, see Dean Zerbe’s article, “179D Tax Break for Energy Efficient Buildings—Update,” at www.forbes.com/sites/deanzerbe/2013/08/19/a-little-known-tax-break-for-building-green/. (back to top)
9 See Charles R. Goulding, Charles G. Goulding, and Rachelle Arum’s article online at www.energytaxsavers.com/pdf/Car Dealers Move Quickly to Complete Tax Incentive LED Lighting Projects.pdf. (back to top)
10 To access the database visit www.dsireusa.org. (back to top)

Jeff Gatzow is national sales and marketing manager, lighting with Optec LED Lighting. He has worked in the LED luminaire industry for over 10 years, and prior to this he worked in the illuminated signage/brand identity industry. Gatzow can be reached by e-mail at jgatzow@optec.com.

Energy Efficiency and Building with Wood: Six Building Lifecycle Steps

Buildings have an impact on people and the environment throughout their entire lifecycle, starting with extracting resources from the earth to putting them back in the earth, or burning them, at the end of their lives. To evaluate the effect of buildings in this regard, everything from the energy they consume, the waste they generate, and the carbon dioxide (CO₂) they emit must be considered throughout the six major cycles below.

The combination of wood and the Passive House standard is a common-sense approach that can have a very positive lifecycle impact on the environment. In fact, according to a report from the U.S. Forest Service, wood in building products yields fewer greenhouse gases (GHG) than other common materials.*

1. Resource extraction
Everything in buildings comes from natural resources, some of which grow relatively quickly above the ground (e.g. wood), while others take millions of years to form below the ground (e.g. materials derived from fossil fuels). Taking a look at wood, the amount of heat, water, and pollution generated compared to extracting iron to produce steel, or extracting limestone to produce cement is significantly lower.**

The lifecycle of wood has a smaller impact. For example, the sun hits the tree, and the tree grows. It can be cut down with light machinery and a new tree is planted. It absorbs carbon, provides oxygen, and can be used in the future. In this context, it means a more sustainable production, compared to making concrete or steel, where digging for oil, coal, or natural gas and then burning it is a prerequisite to extracting the raw materials from the earth.

2. Manufacturing
The real ‘weight’ of a material—including resources, water, and energy used at the entry point of a manufacturing facility—compared to the material that comes out at the other end is referred to as the ‘ecological backpack.’ This measures the environmental impact of manufacturing products. Common sense suggests it requires less resources and energy to manufacture wood products compared to concrete and steel. Heavy timber and mass timber products can meet the same structural and fire requirements that also govern concrete and steel.

3. Off-site and onsite production
In many cases, the process of constructing buildings is antiquated, relying on manual and labor-intensive onsite processes. Other fields, such as manufacturing automobiles, have advanced considerably using automation and an industrialized system approach to designing and building, where the energy efficiency, in miles per gallon, can be guaranteed and the assembly occurs in a modern factory. Modern wood prefabrication processes can offer new opportunities and better working conditions. In this respect, building with wood can offer fast and efficient options for construction.

4. Operation
The natural resources needed to produce and deliver the energy consumed to heat and cool buildings for lighting, appliances, and water is the highest of all six lifecycle steps. While more efficient lighting and appliances can be specified, the only way to reduce long-term heating and cooling loads is to improve the building envelope. Airtightness is the most important element that has made the Passive House standard succeed. It can easily be achieved using modern wood carpentry, as discussed in this article.

5. Demolition
At the end of a building’s lifecycle, products are usually disposed of in landfills. Using a system approach to construction, buildings can be designed so they can be disassembled and separated for recycling. Design optimization, use of recovered wood, and specifying jobsite waste to be separated and taken to a local recovery center are all ways to reduce, reuse, and recycle.

6. Recycling
Wood from buildings can be recovered for use in other buildings or be employed to create furniture or other products. Even at the end of their second or third ‘life,’ wood products can be burned to generate energy or decompose naturally in the earth.

*See USDA Forest Service’s “Science Supporting the Economic and Environmental Benefits of Using Wood and Wood products in Green Building Construction.”
** For more, see the International Journal of Life Cycle Assessment article, “Wooden Building Products in Comparative LCA: A Literature Review,” by Frank Werner and Klaus Richter. Visit www.vhn.org/pdf/LCA-Wood-algemeen.pdf.

To read the full article, click here.

Energy Efficiency and Building with Wood

Photo © Norman A. Müller

Photo © Norman A. Müller

by Nabih Tahan, AIA

In creating energy-efficient buildings, one of the most important goals is to accurately predict during the design stage how a structure will perform when occupied—not only the natural resources used to produce it, but also the ongoing energy consumed for its regular operation. New opportunities combining modern carpentry techniques and the Passive House standard help achieve these goals.

There are three main ways to make a building energy-efficient—using less energy, generating more energy with renewable resources, or taking a combined approach of the two. In this author’s opinion, doing both is the best option. However, it is first important to eliminate heat losses due to design strategies and construction techniques.

In winter, heat in buildings is often needlessly lost due to conditioned air escaping through cracks in the envelope. To replace this heat, heaters are used. Eliminating air leakage and heat loss in buildings by making them airtight is the most important factor for making buildings energy-efficient.

New wood building systems have been developed to offer greater airtightness to minimize energy consumption. The building industry should focus on combining the two aspects of using renewable building materials and energy efficiency to achieve comfortable buildings, while optimizing indoor air quality (IAQ) and reversing the negative effect of climate change. (See “The Six Lifecycle Steps” to understand the advantages of combining wood and energy efficiency when specifying a building system.)

New building materials created through advanced versions of engineered wood are changing non-residential construction. With the right techniques, they can bring about improved energy effi ciency. Photo courtesy Nabih Tahan

New building materials created through advanced versions of engineered wood are changing  non-residential construction. With the right techniques, they can bring about improved energy efficiency. Photo courtesy Nabih Tahan

Europe is far ahead of North America when it comes to monitoring and reporting energy consumption of buildings and homes. This image comes from Ireland’s Building Energy Rating (BER) program for residences. Image courtesy Sustainable Energy Authority of Ireland

Europe is far ahead of North  America when it comes to  monitoring and reporting energy consumption of buildings and homes. This image comes from Ireland’s Building Energy Rating (BER) program for residences. Image courtesy Sustainable Energy Authority of Ireland

Using and measuring energy
It is not enough to design buildings using energy efficiency strategies—they must also be constructed accordingly and then meet the energy consumption goals of the design during operation. This is similar to a car manufacturer designing and producing a vehicle with a specific fuel economy, and then having the car actually meet that target. Everyone is familiar with comparing cars in terms of ‘miles per gallon,’ and now a similar unit of measurement for buildings is needed. At some point, this metric for energy consumption of a building or apartment might even be included in the Multiple Listing Service (MLS).

The European Union (EU) requires every building have an Energy Performance Certificate listing the energy consumption of space heating and cooling, water heating, lighting, and appliances. The certificate must be available to buyers and tenants when a building is constructed, sold, or leased. In Europe, the unit of measurement used for the certificate is kWh/m2/year.

In the United States, energy consumption in buildings is compared to the local energy code requirements in relative numbers as opposed to a consumption rate. Buildings are described as being a certain percentage better than the prevailing code, rather than having their actual consumption cited. As new energy code updates take effect, a similar unit of measurement comparable to the Energy Performance Certificate will be established. In the meantime, the Passive House standard is a good tool to measure and compare how much energy buildings are consuming.

For new-generation wood projects, walls are simply stood up and windows, siding, and trim are installed. Photo courtesy Nabih Tahan

For new-generation wood projects, walls are simply stood up and windows, siding, and trim are installed. Photo courtesy Nabih Tahan

Preparation for blower door test for LCT ONE—a Passive House-certifi ed, eight-story wood offi ce building in Austria. Photo courtesy Cree GmbH

Preparation for blower door test for LCT ONE—a
Passive House-certified,eight-story wood office
building in Austria. Photo courtesy Cree GmbH

 

 

 

 

 

 

 

 

 

 

Passive House and net-zero energy design
Passive House is a European-developed standard that has recently found its way to North America. The original German name ‘PassivHaus’ refers to both commercial and residential buildings. Rapidly gaining popularity in North America, the standard demands high-performing building envelope assemblies and airtightness.1

Passive House calculates energy consumption (in kWh/sf/year), and includes energy-use from space heating, cooling, and ventilation systems, along with water heating, lighting, and appliances. Under the standard, the maximum energy allowed for heating and cooling is 1.4 kWh/sf/year. The standard has become successful because it has proven it can accurately predict, during the design stages, the building’s eventual energy consumption. (This is comparable to a car company claiming a car will get 30 mpg and proving to be correct.) Predicting the energy consumption in the design stages is done with the Passive House Planning Package—an energy modeling tool.

The Passive House standard is a whole building strategy that harmonizes all aspects of a structure beginning with data on local weather and solar orientation and continuing with the design, layout, foundation, framing, and insulation systems to reduce, or even eliminate, thermal bridging. It also optimizes specification of the openings (i.e. doors, windows, and curtain walls), heating, cooling, and ventilation systems, along with lighting and appliances.

Specific to thermal properties, it is important to incorporate building materials that have low thermal conductivities, and design details that minimize thermal bridging. By nature, wood is ideal for this, made up of thousands of open cells that make it difficult to conduct heat. In fact, the thermal properties of wood products are 400 times better than steel and 10 times better than concrete.2

Most importantly, Passive House has a specific requirement for airtightness, which is where the biggest connection to modern wood carpentry is made. Airtightness is measured with a blower door test.3 Air is either pumped into or sucked out of a building to see how much air is leaked, in both pressurized and depressurized states. This is similar to fixing a leak in a bicycle inner tube. Air is pumped into the tube and placed in water and the leaks are found by following the bubbles. For buildings, smoke or other instruments are used to find leaks during a blower door test. If the test is performed before the building envelope is covered up, the leaks can be sealed to make the building airtight.

Lighting and all appliances (including ovens, cooktops, refrigerators, toasters, and computers), generate some heat. Instead of allowing this heat to escape through a leaky building envelope, it is trapped inside a tight building envelope. A mechanical ventilator, with a heat recovery component, brings in fresh air into the living spaces and removes the same amount of stale air from kitchens and bathrooms.

The heat in the outgoing stale air is transferred to the incoming fresh air inside the ventilator. This recycling (or ‘U-turn’) of ‘free’ heat’ that comes out of everyday appliances and lighting can dramatically reduce a building’s energy consumption. Future energy codes in North America will also be targeting a net-zero energy standard. A net-zero energy building is hooked up to the grid and draws electricity and natural gas from the grid. The building also has a source for generating renewable energy such as solar or wind energy. During a one-year period, the amount of energy a building draws from the grid has to equal the energy it generates from renewable resources. The easiest way to meet the net-zero energy standard is to consume less energy, which is where the strategy of Passive House, in combination with modern carpentry, becomes valuable.

To combine this strategy with the choice of materials and construction methods, use of modern engineered wood products—stable, cut accurately with computerized equipment, and assembled under a controlled environment—results in airtight buildings that are automatically energy-efficient.

Prefabrication and modular wood construction is helping building designers achieve this while increasing the speed of construction and reducing project cost. Energy-efficient design is also becoming more important in North America, as the U.S. Department of Environment (DOE) has a goal of all new commercial buildings being ‘net zero’ by 2025.

This photo shows framing lumber cut with computer numerical control (CNC) machinery. Photo courtesy Nabih Tahan

This photo shows framing lumber cut with computer numerical control (CNC) machinery. Photo courtesy Nabih Tahan

Wall elements are produced on tables. Photos courtesy Cree GmbH

Wall elements are produced on tables. Photos courtesy Cree GmbH

 

 

 

 

 

 

 

 

Wood technology
When talking about wood construction, the reference points are traditionally stick-frame, or light-frame residential construction. Modern wood construction falls under the category of heavy timber, using large-dimensioned posts and beams. A new category of mass timber includes cross-laminated timber (CLT)—sometimes referred to as ‘plywood on steroids.’4

The post-and-beam method of wood construction was prevalent in many cities at the beginning of the last century, before the industrial revolution introduced concrete and steel. Now, wood products are beginning to increase again in popularity due to awareness over some of the negative environmental effect of products extracted and manufactured with intensive use of fossil fuels. Of course, this is not to say one product type is always better than another—each material has special properties and they should be combined to make hybrid buildings.

Modern timber products for structural framing are referred to as engineered lumber. These members use smaller pieces of wood, eliminating the need to harvest large trees. The ends of these smaller pieces are finger-jointed and glued to make longer pieces. Several long pieces are laminated together to make large glued-laminated (glulam) post and beams. This lumber is stable and will not shrink or twist because it is dry, which is a great advantage for airtightness, performing much better than traditional stick frame wood with higher moisture content.

For fire safety, heavy timber is allowed under the 2012 International Building Code (IBC). Wood burns approximately 38 mm (1.5 in.) per hour. Therefore, the fire regulations allow the size of structural members to be increased by 38 mm per hour for each exposed member. If a member requires two-hour fire protection, 76 mm (3 in.) are added to the size required structurally. Light-frame construction is similar to kindling for a fire. Heavy timber construction cannot be ignited without kindling; like throwing a large log into a fire, heavy timber members will char, protecting their structural integrity and strength.5

The modern process of carpentry is based on digital, computerized information. The carpentry company receives the computer-aided design (CAD) drawings from the architect. They transfer the drawings to 3D-CAD/computer-aided manufacturing (CAM) program where the wood frame can be looked at in 3D and the structure can be optimized. This is called optimal value-engineered, or ‘smart,’ framing.

Every piece of wood is placed in an exact location and has a purpose. Unnecessary framing members are eliminated and replaced with insulation to optimize energy performance.

The material is then fed to a wood-cutting machine that uses the computer numerical control (CNC) data to precisely cut all the elements. The engineered lumber is stable and is cut precisely and eliminates waste since the members can be 12.1 to 18.2 m (40 to 60 ft) long. The individual pieces are assembled together in a facility, working on tables and prefabricated into wall, floor, and roof elements. These components can be quickly erected onsite in an airtight manner, ensuring energy-efficient construction.

Instead of asking carpenters to measure, cut, and assemble walls and floors onsite, employing labor-intensive processes, the carpenters are moved in a controlled environment, where they are given the drawings and pieces for each component to be assembled, making use of overhead cranes and forklifts to protect their bodies.

The advantage of this process is it optimizes the construction, guarantees stable material, and accurately cut pieces and assembled components that fit together tightly. Specifically designed tapes and gaskets are used at the intersection of panels to prevent air leakage. As proof of performance, the building can be tested for airtightness by a third party by administering a blower door test to meet the ≤ 0.6 air changes per hour @ 50 Pascal pressure—one of the main requirements of the Passive House standard.6

This wall element was craned in place. These types of components can be completed onsite in an airtight manner.

This wall element was craned in place. These types of components can be completed onsite in an airtight manner.

This is an example of precision cutting using CNC machinery. Photo courtesy Nabih Tahan

This is an example of precision cutting using CNC machinery. Photo courtesy Nabih Tahan

 

 

 

 

 

 

 

 

Conclusion
Combining modern wood technology and Passive House strategies helps save resources and achieves energy efficiency in buildings. The fundamentals of modern carpentry are based on:

  • optimizing the timber structure;
  • uses stable engineered lumber;
  • cutting the material accurately using industrial machinery;
  • prefabricating components under a controlled environment; and
  • assembling them quickly onsite to be cost-competitive, while automatically meeting airtightness requirements.

Using this construction process and modern carpentry skills, the building envelope’s thermal performance and airtightness can be predicted during the design stages. To prove the performance, the envelope is tested for airtightness with a blower door test after assembly. Similarly, the energy performance of a building can be predicted using the Passive House standard during the design stages—through the thousands of certified buildings in Europe, the actual energy consumption during occupancy has been shown to match the predicted values.

Overall, the use of new modern wood technologies can have a positive effect on construction industry from job creation to reduced environmental impact.

The design team, including architects and engineers, can collaborate to ensure wood-based building envelopes can meet these high-performance standards. In collaboration with the Passive House consultant, the design team can determine which layer in the wall/floor/roof assemblies prevent air leakage and include details on how to seal intersections and penetrations.7 They can model heat transfer effect in building components to eliminate or reduce thermal bridging and specify available products for taping and sealing joints proven to be durable and long-lasting.8

Notes
1 There have been dozens of certified projects in North America, and the numbers are growing fast. There are two competing U.S. organizations, and both of them have databases and listings for these projects. The North American Passive House Network (NAPHN)—www.naphnetwork.org—is directly affiliated with the Passive House Institute (PHI) in Germany, while the Passive House Institute US (PHIUS)—phius.org—was founded by someone who used to work with PHI, before branching off.
2 For more information, see Naturally Wood’s “Green Building with Wood–Module 3” at www.naturallywood.com/sites/default/files/Module-3-Energy-Conservation.pdf.
3 The Passive House Institute requires the test to meet the European Standard EN 13829, Thermal performance of buildings: Determination of air permeability of buildings, fan pressurization method. In the United States, ASTM E1927, Standard Guide for Conducting Subjective Pavement Ride Quality Ratings, and ASTM E779, Standard Test Method for Determining Air Leakage Rate by Fan Pressurization, would be used with Resnet Protocol Chapter 8, “Enclosure and Air Distribution Leakage Testing.”
4 The limitations of these types of wood assemblies are the current building codes or special approval by a jurisdiction for alternative means of design and construction. Obviously, it is not a one-for-one switch between wood and concrete—the architect and engineers have to run calculations for both materials to ensure the design meets the structural, seismic, acoustic, and thermal requirements. At the moment, the building codes limit wood buildings to 75 ft (i.e. 23 m). The wood industry is in the process of testing new wood products such as CLT for fire and seismic performance. This author’s company is in the process of negotiating a partnership/joint venture agreement to participate in an Expression of Interest for a 16 to 18-story student residence building utilizing advanced wood-based building system, physically demonstrating the applicability of wood in the tall building market.
5 For more on wood and fire resistance, see “Design of Fire-resistive Exposed Wood Members,” by Bradford Douglas, PE, and Jason Smart, PE, which appeared in the July 2014 issue of The Construction Specifier.
6 Visit www.passiv.de/en/02_informations/02_passive-house-requirements/02_passive-house-requirements.htm for more information.
7 This is a consultant that collaborates with the architect, and structural, mechanical, and electrical engineers. During the design stages, the passive house consultant begins the energy modeling in the Passive House Planning Package (PHPP) tool to determine the heating, cooling, and electrical loads. The PH consultant then submits the calculation to either PHI or PHIUS for pre-certification. The MEP engineers use these calculations to design the system, and the architect and structural engineers design the details to eliminate or reduce thermal bridging.
8 For more, see this author’s previous article, “LCT ONE–A Case Study of an Eight-story Wood Office Building,” in the March 2014 issue of The Construction Specifier.

Nabih Tahan, AIA, is an international architect, Passive House consultant, and CEO of Cree Buildings Inc. For more than 30 years, he has honed his knowledge in architecture, energy efficiency, and sustainable timber-based construction methods through work in Austria, Ireland, and the United States. Currently, Tahan is guiding Cree Buildings to establish a systems approach to design and construction, combining wood and energy efficiency strategies to build single-family and multi-family residential projects, along with office buildings. He can be contacted at nabih.tahan@creebuildings.com.

LCT ONE: A Case Study of an Eight-story Wood Office Building

All images courtesy Cree GmbH

All images courtesy Cree GmbH

by Nabih Tahan, AIA

For buildings to perform better, the construction industry must change the way it designs and builds. Lifecycle Tower (LCT) ONE, an eight-story wood office building in Austria, is both a prototype and proof of a concept that demonstrates an innovative process and building. Through its use of wood, LCT ONE focuses on reducing the negative impact of buildings on the environment, while improving comfort and indoor air quality (IAQ) for occupants.

LCT ONE began as a research and development project based on the lifecycle assessment (LCA) of buildings. The motivation was to find a substitute for traditional construction practices that can have negative impacts on local and wider environments. The population is growing and the trends are shifting. People are moving from rural to urban areas. Cities must find new ways to grow around transit systems with sustainable developments that do not deplete resources and harm the environment. Therefore, cities must readapt to the current changes.

The sustainable wood and concrete hybrid building is now occupied and showcases a way of achieving mid-rise and tall buildings that can go up to 100 m (328 ft) and 30 stories.(Figure 1).

Motivation for research project
A sustainable strategy must consider the entire lifecycle of a building and its materials. This includes resource extraction, material production, construction, operation, demolition, and recycling. Since the Industrial Revolution, progress in developing cities translated into more concrete and steel produced with oil and coal, to build tall and mid-rise buildings. LCT ONE was developed to introduce alternatives by substituting renewable resources for fossil fuels, along with systems and processes that can yield better building performance.

Exterior and interior photos of LCT ONE.

Exterior and interior photos of LCT ONE.

Forestry carbon cycle
Wood is a renewable resource that grows from the sun—it is the ultimate solar product. Trees absorb carbon while providing oxygen. Modern timber-based products, such as engineered lumber, are available worldwide. Heavy glued-laminated timber (glulam) members are stable, will not shrink and twist, and can be pre-cut and prefabricated to exact tolerances, which are airtight, resulting in saved energy. At the end of a building’s life, the wood can be reused for other purposes and later turned into fuel and energy.

Further, use of wood is carbon-neutral. In other words, growing forests absorb carbon from the atmosphere and wood products store carbon. It remains stored when wood products are recycled into other products. At the end of their life, bioenergy is produced from these products, as well as from mill and forest residues and reforestation ensures the carbon cycle continues.

Ecological backpack
Selection of building materials should be linked to the use of natural resources, including raw materials (renewable and non-renewable), energy, water, and land. To specify products for the LCT system, data was collected and calculations performed to measure the total amount of natural resources required to produce a certain product or building. Since trees grow above the ground, it is resource- and energy-efficient to extract and produce wood as a building product. Wood has a much lower ecological ‘backpack’ than traditional materials, such as concrete and steel.1

Prefabricated construction process
Austria has a long history of prefabricating high-performance building components out of wood. The process begins with computer-aided design (CAD) software used to cut lumber using computer-numerical-controlled (CNC) machinery. The members are assembled in a carpentry shop, under a controlled environment where windows, insulation, sheathing, vapour retarders, and finishes were installed. The components are made to tight tolerances, can be quickly assembled onsite, and meet the most stringent blower door test requirements. Modern timber technology is available and can deliver high-performance buildings using renewable resources (Figure 2).

Prefabricated timber wall and floor panels for LCT ONE.

Prefabricated timber wall and floor panels for LCT ONE.

Operation and maintenance
Existing buildings consume a lot of energy during their operational life. To reduce consumption, the LCT system was developed according to the stringent Passive House standard introduced in Germany. The strategy is to drastically reduce consumption before relying on renewables. This is the surest path to reach zero net energy. Highly efficient solar and mechanical equipment have an ecological backpack, therefore ‘less is more.’ No need to heat and cool is more sustainable than heating and cooling with renewables or high-efficiency equipment.

The energy modeling software program Passive House Planning Package (PHPP), is an accurate tool for predicting heating demand and peak heating load in low-load buildings. The PH standard is based on energy performance (kWH/m2/year [kWH/sf/year]); in Europe, the predicted energy consumption during the design phase has proven to be accurate when compared to actual consumption during operation.2 These metrics and strategies are valid across different climate regions of the world.

To guarantee maintenance and durability, a building science consultant is part of the integrated design team and advises on the permeability and diffusion of the entire building enclosure. The most important aspect is airtightness, which prevents air and moisture from entering the building enclosure. Additionally, the building’s exterior finish material is always installed on a rainscreen, creating a ventilation layer behind it and allowing any water penetration to drain before it reaches the building enclosure.

Urban mining
All building products originated from mining the earth. At the end of their ‘lives,’ buildings are typically added to landfills and new materials are mined. The LCT research project strived to develop a solution where reusable materials are saved from landfills. Urban mining conserves our natural resources, eliminates potential energy costs, and greenhouse gas (GHG) emissions. When a building has reached its full useful life, urban mining of the LCT system can be activated, extracting materials to reuse, recycle, and convert into bioenergy, thus protecting landfills from unnecessary waste.

System and product development
As a result of the research phase, LCT ONE was designed and built as a proof of concept. The goal was to develop a system and products that can be used on any urban infill projects, but with wood replacing concrete and steel, where possible. The goal was to introduce an industrial process for buildings—similar to the process used by car and computer companies to design and build their products. Instead of miles per gallons, building performance can be guaranteed in kWh/sf/year.

To reach this goal for tall, large-volume wood buildings in urban settings, the LCT system integrates:

  • planning;
  • offsite production and onsite assembly;
  • use and future conversion;
  • dismantling; and
  • recycling of buildings.

Structural system
The LCT system was developed as a core and shell that acts as the structural system and enclosure of a tall, large-volume wood building. This system is analogous to the ‘Intel Inside’ of a computer. It is the hidden operating system on which each manufacturer relies, but each computer looks and performs according to the manufacturer’s design and specifications. Similarly, the core and shell of the LCT system can be looked at as the ‘LCT Inside’—each architectural and engineering team can design the building according to its own aesthetics, integrating the site and client’s program requirements into the design.

Posts and hybrid slabs (left) and LCT ONE interior during construction (right).

LCT ONE interior during construction (left) and posts and hybrid slabs (right).

The core is where the elevators, stairs, wet rooms, and shafts are located. It serves as the building’s stiffening element. While wood is the optimal choice as a material for the core, concrete and steel can also be used until codes enable creation of taller wood buildings.

The gravity loads are carried by a series of heavy-timber glulam posts on the exterior of the building spaced approximately 3 m (10 ft) apart. These posts are exposed on the building’s interior, adding to the warm aesthetic of the space. For fire protection, the size of the post is increased beyond the structural requirements. Approximately 38 mm (1 1/2 in.) of wood for one-hour fire protection is added to each exposed surface of the posts, which creates a charring layer in case of a fire. Wood burns ‘safely,’ because based on fire tests, calculations, and simulation, predictions can be made on how long wood will withstand the flames—therefore, the building codes allow this additional thickness in recognition of the superior fire endurance demonstrated by large wood beams and columns in fires. (Figure 3).

Hybrid wood/concrete floor slabs span about 9.1 m (30 ft) between the exterior heavy timber posts and the core, transferring all lateral forces from the former to the latter. The benefit of a hybrid system is it takes advantage of the properties of each material to meet all the structural, fire, acoustic, and thermal requirements using the least amount of resources and energy. The hybrid slabs were tested in a full-size fire chamber and passed a two-hour fire test.

International Building Code (IBC) requires ASTM E119, Standard Test Methods for Fire Tests of Building Construction and Materials. However, in this case, the tests were performed in Europe according to International Organization for Standardization (ISO) 834, Fire Resistance Tests—Elements of building construction, which is the governing full-scale furnace test.

The design of the slabs provides a built-in fire separation between each floor because there is no wood-to-wood contact between floors.

Integrated building enclosure
The building enclosure is then integrated with the core and shell to give the building its aesthetic appearance. The façade is a curtain wall that withstands wind loads, but not gravity forces. The seismic forces are transferred from the glulam posts to the hybrid slabs through a hinged connection.

Building enclosure and integrated mechanical, electrical, and plumbing (MEP) systems.

Building enclosure and integrated mechanical, electrical, and plumbing (MEP) systems.

The enclosure can be made of any material, but many prefer wood, as it is a renewable resource. The windows, insulation, water, air barriers, vapor retarders, and exterior finishes are designed with the collaboration of a building scientist, mechanical engineer, and exterior wall manufacturer. These sections take into consideration the orientation of the building, as well as the energy performance and standard demanded by the client.

Integrated MEP Systems
Similarly, the mechanical, electrical, plumbing (MEP), and fire protection systems can be integrated within the core and shell and optimized according to the building orientation and enclosure. The systems can be prefabricated and are easily accessible between the structural members. (Figure 4).

Planning process
As a prototype, LCT ONE is proof of the Lifecycle Tower concept. Its foundation and core were built onsite with traditional reinforced concrete construction. The building enclosure was timber frame and the floor elements were made out of the wood/concrete hybrid slabs.

To guarantee performance, the LCT concept is designed to automatically meet the requirements of certification programs. However, as a prototype, it was necessary to compare the LCT system to mainstream certification programs. As mentioned, LCT ONE was designed to meet Passive House and received official certification from the Passive House Institute in Germany. It also applied and received Deutsche Gesellschaft für Nachhaltiges Bauen (DNGB) Gold certification from the German Sustainable Building Council.

Energy standards and certifications
The goal was to meet the energy requirements of Passive House because it has proven to be accurate in predicting actual energy consumption. In collaboration between the engineers and building enclosure manufacturer, the building envelope—as well as the mechanical, electrical, and ventilation systems—were designed to optimize the building performance according to the given location and orientation. By using the PHPP software, multiple reiteration were attempted to optimize the balance between the orientation, building enclosure, mechanical, electrical, and renewable energy systems.

Part of the production process of hybrid slabs and wood in metal frames is shown here.

Part of the production process of hybrid slabs and wood in metal frames is shown here.

Orientation
The building orientation was governed by the property’s existing location. The orientation created a negative effect on the energy balance. The building would have performed better if it could have been rotated by 90 degrees. To mitigate the effect of the orientation, the thermal performance of the building envelope was improved by increasing the thickness of the wall and insulation and specifying higher-performing triple-glazed windows.

Building enclosure
The building enclosure consisted of prefabricated timber frame walls, where the insulation, windows, and sheathing were installed offsite. The connection and intersection between all wall, floor, and roof elements were designed to minimize thermal bridging. Insulation was applied on the exterior of the window frames to decrease heat losses through thermal bridging. All joints were taped to be airtight in order to meet the Passive House blower door test requirements. This test is one of the three requirements needed to meet Passive House certification. It measures infiltration air flow at a pressure difference of 50 Pa. The requirements stipulate it cannot exceed 0.6 air changes per hour (ach) at 50 Pa.

The shape, size, and number of windows were optimized for low heat loss in the winter and low heat gain in the summer, as well as to reduce demand for artificial lighting throughout the year. Tilt-and-turn operable windows were specified to allow for natural ventilation—as they open to the interior, they allowed exterior shading devices to be installed for reducing heat gain in summertime.

Passive heating and cooling
Passive heating is achieved by large windows in the staircase (eastern orientation). The morning sun heats up the concrete wall and heat is stored in the wall’s thermal mass. Passive cooling is achieved by operating the chiller machine in a free-cooling-mode during most of the year. Further, the optimized ratio between transparent windows and opaque walls, as well as deep window reveals, prevents the office building from overheating in the summer.

The production of timber frame walls is shown here.

The production of timber frame walls.

Building system
The following building systems were used on LCT ONE:

  • heating system: district heating system—renewable-fueled combined heat and power;
  • cooling system: conventional chiller machine with enhanced free-cooling-option;
  • hot-water system: highly efficient, decentralized water boiler on each floor;
  • heat recovery ventilation: central system installed in basement with carbon dioxide (CO2) sensors on every floor that control the amount of air introduced;
  • lighting: fully automated and daylight-dependent lighting system (including motion detection), automated dimming and zoning, and daylight-dependent shading operation and positioning;
  • services: fully automated building services system;
  • controls: motion and window detector controlled heating and cooling, as well as CO2 sensors;
  • waterless urinals; and
  • photovoltaics (PV): 10-kW (peak) rooftop system—prepared for future installation of a 10-kW PV on the southern façade, which will be required to become a zero net energy building.

Verification
Blower door tests were conducted in two stages. The first was a random test at two floors performed after the installation was completed. (The core was excluded.) The result was 0.35 ach at 50 Pa. Before commissioning, a blower door test was performed on the entire building, including the core. The results were 0.55 ach at 50 Pa, meeting the Passive House standard.

Construction process
While foundations and concrete core where being built onsite, the wall elements and the hybrid wood/concrete floor slabs were produced offsite. The assembly of the wall and hybrid floor elements took eight days onsite, one floor per day.

Producing slabs
The industrial production of the hybrid wood/concrete slabs took place in a precast concrete shop. The heavy timber glulam beams were supplied by a lumber manufacturer who cut them accurately with CNC machinery and attached the required metal fasteners and connectors. The beams were delivered to a precast concrete manufacturer, who placed them in metal forms, added metal reinforcement and poured the concrete. This process was repeated daily for each form. The advantage of this system is it allows the concrete to cure offsite and prevents additional moisture into the building. Additionally, prefabricated slabs are assembled quickly onsite (i.e. eight minutes per slab) to tight tolerances (Figure 5).

LCT ONE on day two, four, and eight of the installation process.

LCT ONE on day two, four, and eight of the installation process.

Producing walls
The walls were produced in a local carpentry shop. Engineered lumber was used for all wood members, including studs. The panels were produced on tables, horizontally, where the timber frame, sheathing, and insulation were installed. After standing up the walls, the windows were installed. All joints, including around the windows, were sealed airtightly with high-performance tapes (Figure 6).

After production, all the slab and wall elements were shipped to the site and assembly began. Five skilled carpenters were able to assemble all the components, water- and airtight in eight days, for all eight stories (Figure 7).

To verify the energy standard will be met, blower door tests were performed twice as mentioned—once when the installation was done and again before commissioning.

Conclusion
LCT ONE begins with the premise the building industry does not automatically have to rely on concrete and steel for all urban buildings; it demonstrates there is the opportunity to substitute timber for many applications.

Wood is a renewable resource. Essentially, while one building is in construction, the sun is producing the timber for the next building. Timber technology has advanced, where modern industrial machinery and processes make it possible to erect timber buildings quickly, economically, and according to all building regulations and high-performance standards.

LCT ONE is pioneering a new way of building, based on guaranteeing performance. It was developed according to a system that can be the shell and core, while still offering flexible design solutions and architectural and aesthetic possibilities to make each building unique. By following this ‘system approach,’ the performance of buildings can be guaranteed, similar to the performance of cars, computers, and other products manufactured through industrial processes.

The LCT system can be applied as a worldwide solution. With its introduction in Europe and now beginning in North America, it serves as an inspiration to wean the traditional building industry away from only fossil-fuel-intensive products and systems. Less-developed countries, especially those with forests, can adapt the LCT system to modernize their building industry. They can introduce new sustainable forestry management policies and begin manufacturing modern, engineered lumber products to build high-performance timber buildings. A new process of education to create new green jobs and affordable housing solutions could be an alternative to attempting to develop building solutions that rely on fossil-fuel-based resources that less-developed countries do not have and cannot afford.

Notes
1 For more on the ‘ecological backpack’ concept, see M. Ritthoff et al’s Calculating MIPS: Resource Productivity of Products and Services, at epub.wupperinst.org/frontdoor/index/index/docId/1577. See also K.-H Robèrt et al’s “Strategic sustainable development–selection, design, and synergies of applied tools” in the June 2002 issue of Journal of Cleaner Production. (back to top)
2 For more information visit, www.cepheus.de. (back to top)

Nabih Tahan, AIA, is an international architect, Passive House consultant, and vice president of business development for Cree Buildings. For more than 30 years he has honed his knowledge in architecture, energy efficiency, and sustainable timber-based construction methods through work in Austria, Ireland, and the United States. In 2005, his own retrofitted home became the first Passive House home in California. Tahan also acts as the North American ambassador for Cree Buildings, and educates architects, developers, building engineers, and municipalities on the potential of tall wood buildings. He can be contacted at nabih.tahan@creebuildings.com.