Application of laser micro incisions in the fire-retardant treatment

In the fire-retardant treatment of wood by the vacuum-pressure impregnation method, the effect of laser micro incisions (LMI) was verified. Even with the fine incisions with a diameter of about 75 µm, uniform penetration of the fire-retardant was observed by fluorescent X-ray analysis and X-ray CT, even at a hole density of 5 holes/cm2. In the evaluation of fire resistance using cone calorimeter, the "Quasi-non-combustible" performance, which is the standard of the Building Standard Law of Japan, was obtained under the LMI conditions of 6 mm depth.