Notes
(*1) Big-Frame construction method is Japan's first wooden beam Rahmen structure developed by Sumitomo Forestry.
(*2) Big-Column is laminated wood with a large cross section of 560mm, which is the basis of the BF construction method's structure. (Approximately five times thicker than the commonly used 105 mm square columns commonly used.)
(*3) Metal-Touch Joints strongly secures the joint point between the column and foundation to ensure resistance against pull-out.
(*4) Typhoon No. 15 in 2019, which caused extensive damage in Chiba Prefecture, recorded a maximum instantaneous wind speed of 57.5 m/sec.
(*5) Response to exterior walls: In cases where the rainwater intrudes through a wall, the polymer absorbent in the "translucent polymer waterproof sheet" attached to the outside of the wall absorbs the water and expands while gelling to seal the entry opening and protect the structure.
Response to under/above floor: In the event of flooding, the sleeve for draining water accumulated in the foundation enables recovery in the early stages of flooding.
Response to the roof: Our original roofing that ensures high watertightness on the entire surface under the roofing material will ensure excellent water resistance.
(*6) The framework that supports the building.
(*7) ZEH (Net Zero Energy House) refers to a house with a household energy balance of zero or less by means of energy conservation through high-insulation specifications and high-efficiency equipment to reduce energy consumption, and energy creation through solar power generation systems, etc.
※The information is current as of November 2022. The listed performance values are subject to change due to technological improvements.
Providing Housing Using the Big-Frame (BF) Construction Method, Which Can Withstand the Largest Typhoons
Sumitomo Forestry Co., Ltd.
| Publication date | December 14, 2022 (Posted on January 12, 2024) |
|---|---|
| Sector | Natural Disasters and Coastal Areas / Life of Citizenry and Urban Life |
Company Overview
Since its establishment in 1691, Sumitomo Forestry Co., Ltd. has expanded its business scope from forest management in Japan and overseas to distribution and manufacturing of timber and building materials, housing business in Japan and overseas, and biomass power generation business, based on the needs of the times. In recent years, the company has also been promoting medium- and large-scale wooden construction projects in order to realize "Environmentally-friendly timber-based cities," in which towns are transformed into forests.
Climate Change Impacts
While natural disasters are predicted to become more severe as climate change progresses, the number of large-scale natural disasters caused by tsunamis and typhoons has actually increased in recent years, causing enormous damage to the economy and threatening society and our daily lives.
Adaptation Initiatives
We have developed our proprietary wooden beam Rahmen structure, "Big-Frame (BF) construction method (*1, Fig. 1)". This construction method uses “Big-Column (*2, Fig. 2)" as the main structural material and "Metal-Touch Joints (*3, Fig. 2) ” which are bonded together. This method has the features listed in the table below, making it possible to provide houses that are resilient to earthquakes and strong winds.
| Natural Threats | Functions/Features |
|---|---|
| Earthquake | In an experiment on a full-scale model of a three-story building, it was demonstrated that it could withstand the level of seismic waves of the Great East Japan Earthquake. |
| Fire | Due to its high fire resistance, the standard specification of the house is compatible with the “Ordinance Quasi-Fireproof Structure” defined by the Japan Housing Finance Agency, and it can also be used for fire-resistant structures. |
| Wind and rain | In the typhoon performance test, the following performance was demonstrated
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In addition, by using wood with high heat-insulating capacity for the structural frame (*6) and filling the building with high-performance heat-insulating material without gaps, the building provides an energy-saving lifestyle that controls the effects of outside temperatures, enabling comfortable "evacuation at home" even in times of disasters (Fig. 3).
Effects / Expected Benefits
Our original "BF construction method" housing will ensure the safety of residents and protect their properties from natural threats. Adding ZEH (*7), solar power generation systems, wall-mounted storage panels, and rainwater tanks to the "BF construction method" will enable residents to live comfortably every day and during "evacuation at home" in the event of a large-scale disaster.
