Evaluation of fire-retardant wood treated with poly-phosphatic carbamate using a cone calorimeter

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 3 , specimens showed the performance of fire-retardant material. When there was more than 160 kg/m 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 2 in weight), the fire-performance criterion of the specimen remained the same.