"The Shoko-Kan Tokugawa Museum" Reopens with The "-AOI- Three Generations of Tokugawa Shoguns" Exhibition

November 13, 2000

"The Shoko-Kan Tokugawa Museum" Reopens with
The "-AOI- Three Generations of Tokugawa Shoguns" Exhibition
Controlling pollutants that are archenemies of cultural assets
From the beginning of the work to completion, the waiting period until opening was greatly reduced

Takenaka Corporation

As Takenaka Corporation (Head Office: Osaka; President: Toichi Takenaka; Capital: 50 billion yen) was able to keep to a minimum the occurrence of ammonia and formaldehyde that are harmful to cultural assets (*), construction of "The Shoko-Kan Tokugawa Museum" (Mito City), which has received approval from the Agency for Cultural Affairs to display national treasures, has been completed since work began in an unprecedented short 14 months.
Through thorough management of the construction, making careful selection of the construction materials including all the materials to be used in the exterior, interior and showcases, and making adjustments to the design and equipment including the air-conditioning system, the emission of harmful substances was greatly reduced and the museum could be opened in a short period of time.
Work began on "The Shoko-Kan Tokugawa Museum" in May, 1999 and was completed in July, 2000. It will reopen on November 14, 2000 with the "-AOI- Three Generations of Tokugawa Shoguns" Exhibition, a subject catching a lot of attention with the running of the NHK epic drama.

(*)

In order to protect cultural assets, it has been determined that the air environments for storing and displaying items in art galleries and museums must be kept at an optimal level. With a newly constructed building, to reduce the concentration of ammonia that is emitted from concrete, it is normal to begin work on the interior after waiting for a one or two year "seasoning period" after the framework has been completed. Furthermore, to keep the levels of ammonia and formaldehyde low after construction has been completed, it is especially important to carefully select the materials to be used for the interior.

Exterior appearance of the
"Shoko-Kan Tokugawa Museum"

The Shoko-Kan Tokugawa Museum holds about 30,000 items, centered on personal effects of Ieyasu Tokugawa. In preparation for the "-AOI- Three Generations of Tokugawa Shoguns" Exhibition that coincides with the reopening of the museum on November 14, 2000, some 180 displays including national treasures and important cultural properties are being brought into the museum for the first time. Included among these are 27 nationally designated cultural properties (containing 54 items).
For the museum to display national treasures, the building must clear the environmental conditions set down by the Cultural Properties Protection Act. To meet these requirements, Takenaka has carried out intensive considerations with regard to the design and the construction with the Tokyo National Institute of Cultural Properties.

The mission was to keep the concentration of ammonia emission under "20 ppb"

The first challenge was to try and keep the concentration of ammonia emitted from concrete after construction under the extremely low level of "20 ppb," so samples of all the different types of cement and aggregates that have been used in art galleries and museums around the country were collected, and beforehand, rigorous selection was made of materials. After the frame had been constructed, four driers were used to dry the concrete, and the target of keeping the emission of ammonia under "20 ppb" was achieved with just four months of seasoning, between August and November, 1999. Normally, work on the interior begins after a thorough seasoning period (ideally between one or two years), but because the quantity of pollutants was controlled at the material selection stage, the period between beginning the work and reopening the museum was greatly reduced.

Air conditioning used in the display cases to effectively eliminate acetic acids

Display room inside the
"Shoko-Kan Tokugawa Museum"

Air-conditioning equipment used at the "Shoko-Kan Tokugawa Museum"

Also, with regard to the display cases, care was paid to contamination by pollutants during all the processes, careful selection was made of materials that did not emit any pollutants such as formaldehyde, and the materials were wrapped before they were brought in. Airtight display cases that do not use air conditioning are mainly used in museums and art galleries, but for this museum, in order to eliminate any acetic acids from the materials used in the display cases in a short period, an air-conditioning system was decided upon. It is said that it is difficult to stabilize the temperature and humidity in a small space like a display case using air-conditioning, but a control pattern slowly moving the air with a gentle breeze was used, and by adding a "chemical filter" that is used in semiconductor plant clean rooms, it was possible to effectively eliminate acetic acids.

A double-layered structure resistant to any influence from the outside air

Fundamentally, cultural assets, which contain a lot of fiber and paper materials that can easily deteriorate, should be stored in a condition where there is absolutely no influence from the outside air or sunlight. However, museums must contend with two contradictory conditions: while storing its collection for future generations, they have to provide a display environment for visitors to enjoy viewing the collection.
For the Shoko-Kan Tokugawa Museum, a structure was used that gives the most resistance to the archenemies of display items such as changes in the temperature and humidity of the outside air, and sunlight. The building is a double-layered structure consisting of two "30 centimeter thick walls," in other words it is a building within a building. "Chemical filters" are used in the air-conditioning system, and of course any ammonia or other pollutants emitted from visitors and the building are also eliminated.

The best technology for art gallery and museum display and storage environments
At Takenaka, in order to achieve the best air environment for public display facilities for cultural assets, proposals are made with overall technological strength from the planning to the design and construction stages. Technology that does not emit pollutants (material selection and evaluation technology, ammonia-free concrete) and elimination technology (air purification technology) have been used in other projects as well as the Shoko-Kan Tokugawa Museum.
In the future, Takenaka is committed to improving the overall quality required by art galleries and museums by making overall proposals including earthquake resistance technology, technology to maintain a clean environment in the building and the technology to construct high quality spaces in a short period of time.

Outline of the Shoko-Kan Tokugawa Museum

Location	1-1215 Migawa, Mito City, Ibaraki Prefecture
Owner	Suifu-Meitokukai Foundation
Structure/Number of floors	Reinforced concrete, Steel, 2 Fl. above ground
Design	Takenaka Corporation
Construction	Joint venture between Takenaka Corporation, Shimizu Corporation and Aoki Corporation
Total floor space	Newly built area: 885 m² Renovated area: 660 m²
Work period	May, 2000 to July, 2000
Opening	November 14, 2000

Tokugawa Museum Web Site
http://tokugawa.gr.jp/English.htm