Towards a Sustainable Japan--Corporations at Work Article Series No.47
Pursuing Sustainable Architecture - Takenaka Corporation
http://www.takenaka.co.jp/takenaka_e/index.html http://www.takenaka.co.jp/takenaka_e/enviro/enviro.html

An Office Building Where Staff Use the Stairs Instead of the Elevators

Just one minute away from Tokyo Metro Toyocho-station stands Takenaka Corporation's Tokyo Head Office building. The 7-story building opened September 2004, with a total floor area of approx. 30,000 square meters. Takenaka sees this building as a field experiment in the "Sustainable Works" concept. Walking in from the main entrance, you feel warm sunshine coming in from the high cathedral ceiling On the wall of a large meeting space is a screen showing real-time changes in the building's energy consumption and CO2 emissions, which makes you feel as if the building is breathing like a living thing.

This building is equipped with numerous up-to-date environmental architecture technologies: these include effective use of natural light, heat and wind, outer walls made of used and recycled materials, rooftop greenery, and an IT-based energy use management system. One outcome has of course been higher environmental performance, including zero emissions of mixed waste during construction and CO2 emissions 25 percent lower than an average building during operation.

The "Comprehensive Assessment System for Building Environmental Efficiency (CASBEE)," an environmental efficiency rating scheme, awarded this building the highest rank of "Super," with an environmental efficiency rating of 4.9. These features have attracted more than 10,000 visitors from around Japan and abroad who want to see one of the best in-practice examples of environmental architecture.

One interesting characteristic of this building is the fact that Takenaka staff actually use the stairs. The office spaces on the 2nd story and above have a very open layout that allows staff to see how others are working - not just on their own floor, but also on the floors above and below them. At the center of the building is a stairwell bright with sunlight coming down from the cathedral ceiling. The staff seems comfortable going up and down these stairs, enjoying the view and a chat with colleagues passing by.

"It is common for us to use the stairs for not just for the 3rd or 4th stories, but even for the 7th story - although there is an elevator. This makes quite a difference in terms of energy use," says Dr. Sasaki, head of Takenaka's environmental office. This is an embodiment of Takenaka's "Sustainable Works" ethic, which is defined as "an initiative that aims to construct sustainable buildings and housing together with customers, [and] to create spaces in harmony with the environment."

Takenaka Corporation and Other Major Japanese Construction Giants

Takenaka Corporation's roots go back almost 400 years, to 1621 when its traditional architecture masters started to work on building shrines and temples. The company has been developing traditional architecture techniques and methods over the years since then, in the meantime growing into one of Japan's "big 5" construction companies. Its consolidated annual sales were approx. US$ 11 billion in fiscal 2005. Takenaka's famous works include Tokyo Tower, Tokyo Dome, and the National Theatre.

The main difference between Takenaka and other major construction companies is that it is specialized in "architecture." Generally speaking, construction companies have two lines of businesses - "architecture" and "civil engineering." The former involves the design and construction of architectural works such as buildings and large facilities, mainly in cities. The latter mainly involves the construction of public infrastructure such as bridges and dams. Most of Takenaka's sales come from the former. This concentration on architecture is reflected in the composition of its workforce; about one-third of its employees (2,707 out of 7,666) are registered architects. This probably makes Takenaka the company with the highest number of full-time registered architects in Japan.

Another difference is that Takenaka tends to work on projects from design straight through to construction. In some European countries, the same company cannot be in charge of both design and construction. However, this is allowed in Japan, where construction companies can accept three types of orders. One is for design only, the second is for both design and construction, and the third is for construction only. If you as a construction company want to propose an environmental architecture design to your customer, and if you receive an order for the design only, or for construction only, then there are considerable limits to the extent you can incorporate the design concept. "At Takenaka, 50 percent of our projects are for both design and construction. This functions as a strength when we try to incorporate the 'Sustainable Works' concept in all phases of the building life cycle," points out Dr. Sasaki.

From Green Building to Sustainable Works

It was back in 1971 when Takenaka first started to address environmental issues. It was rare in those days for companies to talk about the environment, but Takenaka introduced "environmentally-friendly architecture" under the slogan of "Green for Design." Takaneka has been pursuing environmental architecture since then, and in 2004, based on its accumulated technology and experience, introduced the concept of "Sustainable Works" to help create a sustainable society with a healthy environment to leave to future generations.
Sustainable Works
http://www.takenaka.co.jp/takenaka_e/enviro/images/pdf/e_2006-7.pdf

Customers tend to have amorphous desires regarding the environmental aspects of their buildings, something like, "we want greenery" or "we want to conserve energy." It is the task of architects/engineers to take those desires and create a concrete proposal supported by proved experience and technologies. Takenaka architects/engineers use a tool known as the "Sustainable Works Framework," which consists of matrix with two axes.

Buildings have three lifecycle phases - design, construction, and operation. The Framework takes this time horizon as one axis, with evaluation as the other axis, which measures improvements in environmental quality/performance, and reductions in environmental loads.

Three standards are applied to quality/performance, including "a comfortable residential environment," "long-term building use," and "a tendency to create, maintain and nurture a rich landscape". There are also three standards for environmental loads, including "efficient energy use," "careful use of items not easily disposed of" and "avoidance of polluting activities." The Sustainable Works matrix is made up of these two axes (3 temporal elements x 6 evaluation elements.)

In using this matrix in trying to map out the customer's overall desires, Takenaka architects/engineers plan which elements to emphasize and then how to strike a balance in terms of environmental measures throughout the building's life cycle.

The design is then evaluated using a self-assessment/environmental labeling tool for environmental architecture called CASBEE (Comprehensive Assessment System for Building Environmental Efficiency), developed in Japan for asset evaluation. It is similar to the LEED (Leadership in Energy and Environmental Design) tool used in the U.S. The CASBEE evaluation formula is environmental quality/performance over environmental load, and there are 5 ratings - S (Super), A, B+, B-, and C. In fiscal 2005, Takenaka succeeded in producing 21 buildings with A or S ranks; included is a shopping mall, the Aeon Chigusa store. Takaneka plans to produce more than 17 buildings with A or S ranks in fiscal 2006.
About CASBEE;
http://www.ibec.or.jp/CASBEE/english/index.htm

Long-term use of buildings - The Attractive Renaissance Initiative Long-term use of buildings is one key aspect of environmental quality/performance. One of the reasons why it has not been a prominent concern in Japan, although it is common in Europe, is the existence of frequent earthquakes. Seismic-resistance standards have tended to become more and more stringent as technology progresses, and therefore it often turns out that older buildings meeting former standards do not fit for newer standards. It is not unusual for building owners to decide to re-build for this reason. However, due to improvements in architecture technology and increasing awareness of the environmental impacts of this "scrap and build" style, "re-building" is now possible that make buildings more resistant to seismic activity as well as more attractive, as an alternative to scrapping the whole building.

In answer to increasing customer demands for ways to reuse their buildings besides rebuilding or simple renewal, Takenaka revamped existing technologies and know-how related to evaluating and diagnosing problems and effectively using existing buildings. It then pursued new technologies for assessing the value and business potential of buildings, and introduced "attractive renaissance architecture" aimed at the used building real estate market as part of their Sustainable Works concept.

One prime example of "attractive renaissance architecture" is a project involving Kaijo Junior & Senior High School. In this case, by using what is called "Takenaka Re-Structure to the Sky" (TRSS) technology, Takenaka succeeded in adding three stories of classrooms on top of a four-story building while it was being used. The weight of the three-story expansion was approximately 3,000 tons. The existing building weighed 6,000 tons, which meant the total weight of the remodeled building increased by 50 percent. Normally in this kind of situation, it is necessary to strengthen pillars and foundations. However, when such reinforcement works are combined with a seismic isolator, they can be limited to the outer parts of the building, enabling the interior to be used while the extension is under construction.

Looking at this method from an environmental perspective, it used just 3,000 tons of new materials, whereas the conventional "scrap and build" approach would have produced 6,000 tons of waste and used 9,000 tons of new materials.
Takenaka's attractive-renaissance architecture
http://www.takenaka.co.jp/takenaka_e/enviro/images/pdf/e_2006-2.pdf

To become masters of the operation

More than a year has passed since Takenaka's new Tokyo Head Office building opened in September 2004. Dr. Sasaki comments on where they want to go from here. "Looking at the life cycle of a building, about 60 to 70 percent of CO2 emitted is from operation stage. CO2 from operation must be reduced and we at Takenaka must learn to be the 'masters of the operation phase' and then provide this know-how to our clients."

Numerous data on the operation of the new building have been obtained and it was found that some parts are not operating as effectively as planned, while other parts can be more energy-efficient than planned by adjusting the equipment systems to more appropriately match prevailing conditions.

Takenaka now plans to carry out further studies on effective operation utilizing existing equipment while reducing energy consumption, bringing together personnel from design, construction, and facility management departments to analyze operational conditions and data.

Takenaka's "Sustainable Works" have just started. We expect that many examples of sustainable architecture will be produced along the lines of this framework.

(Staff Writer Kazunori Kobayashi)

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