Shelter Co. has obtained approval from the Ministry of Land, Infrastructure, Transport and Tourism for the product, meaning it cleared standards that are required of buildings with 15 or more stories. The technology will allow large-scale facilities to be built entirely of wood, company officials said.
“Japan has a tradition of wooden buildings, such as Shinto shrines and Buddhist temples, that are unparalleled in the world,” said Kazuyoshi Kimura, 68, Shelter president.
“We would also be able to pursue urban planning with wooden buildings even when it comes to modern architecture, where fire resistance and safety are required.”
Kimura explained at a news conference in Yamagata that the pillar product has a three-ply structure in which a rectangular wooden pillar bar is wrapped in plasterboards, which are in turn covered with another layer of wood from the outside.
The wooden surface and the wet plaster defended the interior pillar in an experiment where the product was burnt for three hours in a furnace at a temperature of about 1,000 degrees.
The rectangular wooden bar inside was found without any burn marks even after the product was left in the furnace for an additional nine hours, the officials said.
Shelter obtained a patent for the invention in 2009. Previously, the company made wood products that can withstand fire for one hour in 2013, and came up with two-hour fire-resistant wooden products in 2014. Those products are usable in pillars, walls and other building components.
The latest, three-hour fire-resistant product would allow high-rise structures to be built of wood under Japan’s Building Standards Law, Shelter officials said.
Shelter is planning to share the production method and other information about the new contraption with members of the Japan Fire-proof Wooden Building Construction Association.
The product can be made by combining raw materials on a construction site. Shelter said it would not collect patent fees, but instead obtain income in accordance with the quantity of pillars and other components used by others.
Hiroyuki Adachi, 51, Shelter managing director, said that business talks are under way regarding, among other things, an 11-story building in Tokyo and a nine-story university dormitory.
Use of the new wooden product is expected to allow construction periods to be shortened because it obviates the need for drying concrete and other processes, which makes it “more reasonable from the viewpoint of costs than the use of a steel frame and concrete,” Adachi said.
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