Preliminary Test of 90 min. Fireproof Structural Assemblies
The Japan 2×4 Home Builders Association and Canada Wood Japan jointly conducted a preliminary test of 90 min. fireproof wall structure on August 22nd, and Yusuke Neriko, technical manager of Canada Wood Japan, witnessed the test. MLIT(Ministry of Land, Infrastructure, Transport and Tourism) relaxed regulations of fireproof structure, and you can design fireproof buildings with 90 min. fireproof walls up to 9-storey, but the current 90 min. fireproof wall requires 3-layer gypsum boards, and due to the heavy weight and a lot of on-site work, that structural requirement is a major barrier to construct mid-rise wooden buildings.
In order to increase mid-rise wooden buildings, it is necessary to develop 90 min. fireproof structure walls with 2-layer gypsum boards. The aim of the test was to confirm the viability of 2-layer fireproof walls, and two specimens were tested. One specimen consisted of 25mm + 25mm gypsum boards. The other consisted of 21mm + 25mm gypsum boards. The results were 25mm + 25mm structure had possibility to meet 90 min. fireproof structure, but 21mm + 25mm structure started to be burning and it would be difficult to develop the fireproof structure with this combination. After this test, we will conduct another preliminary test and confirm a test specification for ministerial approval. This fireproof structure test program is overseen by Dr. Suzuki, fire expert from BRI (Building Research Institute of Japan), and 2×4 association and Canada Wood Japan has been developing suitable test specimens.