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In 1998, the Building Standard Law of Japan was revised to emphasize performance-based regulations rather than conventional conformity to specifications. The method of evaluating fire-retardant material was also changed and the cone calorimeter test was adopted. Although chemical agents that contain phosphorus and nitrogen are widely used to make fire-retardant wood, there are few results of cone calorimeter tests to show the relationship between impregnated quantity of fire retardant and its performance. In this study, a commercial fire retardant whose main component is poly-phosphatic carbamate was impregnated in a 15-mm-thick Japanese red pine specimen, and the fire performance was tested by the cone calorimeter test. When the impregnated fire retardant was over 80 kg/m^sup 3^, specimens showed the performance of fire-retardant material. When there was more than 160 kg/m^sup 3^ of fire retardant, specimens met the criteria of quasi-noncombustible materials. However, it is not always desirable to put chemically treated materials on the surface where people can touch. The fire-retardant properties of wood specimens whose surface was covered with untreated veneer were also tested by the cone calorimeter. When the thickness of the veneer was 0.5 mm (230 g/m^sup 2^ in weight), the fire-performance criterion of the specimen remained the same.
In Japan, the Building Standard Law determines the fire-retardant performance necessary for building materials. The law was revised in 1998 (The Building Center of Japan 1999). The purpose of the revision was to shift emphasis away from conventional specifications toward performance-based regulation. With this revision, the method of evaluating fire performance also changed.
Fire performance materials in Japan are classified into three categories: non-combustible material, quasi-noncombustible material, and fire-retardant material. The noncombustible material is determined in the Building Standard Law, Article 2 item 9, and its required performance is set up in the Building Standard Law Enforcement Order Article 108-2. The article says that building materials having noncombustibility shall be those that are certified by the Minister of Land, Infrastructure, and Transport as having the properties mentioned in each of the following items (excluding number 3 in the case of those used for external finish of buildings) during the testing time of 20 minutes.
1. Materials that do not burn;
2. Materials that do not deform, melt, crack or become otherwise damaged...