Optimization of the wood-based fire protection layer - An engineering approach to the design of fireresistive building elements based on a sacrifice-layer concept

Strategy for the development of wooden structural elements with self-extinguishing performance based on a sacrifice-layer concept was studied through a series of bench scale tests. The typical structural elements composed of two layers and structural part: the first is sacrifice layer (chemically untreated wood), the second is fire barrier (fire retardantand untreated load bearing wood. It has revealed that the thickness of sacrifice layer is important to achieve self-extinguishment of timber elements. All the sacrifices layers should be burnt and glow at around the end of the heating period following the ISO 834 standard curve. It has resulted in the development of Japanese-cedar based 1-hour fire-resistive beam. only with small test apparatuses available almost everywhere, demonstrating its advantage for the technical development in the districts not accessible to large furnaces.