Korea Forest Service "Structural Glued Laminated Timber Safer Against Fire Than Concrete"

On the 16th, the National Institute of Forest Science announced that domestically produced advanced engineered wood products, structural glued laminated timber and structural cross-laminated timber panels, have passed fire-resistance standards, making them applicable to wooden apartments.

Difference between engineered wood structural glued laminated timber (left) and structural cross-laminated timber (right). Photo by National Institute of Forest Science

Engineered wood products have the advantage of maintaining structural stability even when exposed to high temperatures due to their fire-resistance performance. When exposed to high heat, a char layer forms on the surface of the engineered wood, which inhibits combustion and prevents the spread of fire.

Previously, engineered wood products recognized as having 2-hour fire resistance were applied in the five-story "Hangreen Wooden Hall" completed in 2018 in Yeongju, Gyeongbuk Province.

Last year, the columns and beams made of structural glued laminated timber were recognized as having 3-hour fire resistance. Unlike reinforced concrete, which shows a 90% loss rate when a fire occurs, the loss rate of wood is only 25%, providing evidence that using engineered wood with excellent durability and fire resistance can allow structures to stably bear loads better than reinforced concrete during fire situations.

Fire-resistant structures are designed so that buildings do not easily collapse when a fire occurs, securing evacuation time.

In particular, fire-resistant structures in wooden buildings are designed so that the remaining wood can support loads even after a fire. In Korea, according to the "Building Fireproof Structure Regulations," buildings with four floors or fewer must have fire resistance for one hour, buildings with 5 to 12 floors for two hours, and buildings with 13 floors or more for three hours.

Structural glued laminated timber and structural cross-laminated timber panels are engineered wood products that have passed these fire-resistance standards. Structural glued laminated timber is made by removing defects from wood, arranging the wood fibers parallel to each other, then bonding and laminating them, mainly used for columns and beams. Structural cross-laminated timber panels are made by laminating wood with fibers oriented crosswise, used for walls and floors.

Lee Sang-min, head of the Wood Engineering Research Division, said, "We will continue to develop fire-safe engineered wood products so that wooden architecture can contribute to carbon neutrality."