Yunjeong Choi

Protective coverings are an effective means of preventing direct fire exposure and delaying the charring of cross-laminated timber (CLT). This study evaluated the effects of practical covering configurations on the fire behavior and charring characteristics of four Korean larch CLT wall assemblies through 120-min fire resistance tests. The specimens varied in fire-resistant gypsum board thickness, joint arrangement, fastening details, and insulation conditions. Fire-induced damage, internal temperatures, and post-fire charring characteristics were evaluated. Specimens with non-staggered gypsum board joints exhibited cracking and detachment of the protective covering, resulting in localized flame penetration, with a maximum measured localized charring depth of 80 mm in CW-WS-G-1 and a measured localized charring depth of 73 mm in CW-WS-G-2. In contrast, specimens with staggered joints and improved fastening details largely maintained covering integrity. Only minor surface charring was observed in CW-WS-G-3, while no distinct charring occurred in CW-WS-W-1. The highest temperature recorded by the installed thermocouples was 225.2 °C in CW-WS-G-1, whereas the highest recorded temperatures in all other specimens remained below 100 °C. Nevertheless, localized charring occurred in CW-WS-G-2 despite its low internal temperature, indicating that temperature measurements alone may not adequately capture localized fire damage. These results indicate that, within the tested configurations, covering integrity associated with the combined joint arrangement and fastening details played an important role in limiting localized flame penetration and charring.

Due to the increasing demand for sustainable construction materials, wood has gained prominence owing to its renewable nature and carbon-storage capabilities. However, the flammability of wood presents critical safety concerns in its structural applications. This study investigates the combustion and charring characteristics of three Korean softwood species, namely Larix kaempferi, Pinus densiflora, and Pinus koraiensis, which were subjected to varying levels of radiant heat using cone calorimetry testing (ISO 5660-1). The fire performance was evaluated based on the peak heat release rate (HRR), total heat release (THR), surface ignition temperature, and char depth. The obtained results showed that Pinus densiflora exhibited rapid ignition and the highest THR (62.2 MJ/m²), indicating an aggressive burning behavior. Additionally, Pinus koraiensis recorded the highest peak HRR (241.6 kW/m²). In contrast, Larix kaempferi showed the most favorable fire-resistance profile, with the highest ignition temperature (~300 °C), lowest THR (31.8 MJ/m²), and shallowest char depth (7.5 mm), suggesting slower pyrolysis. These findings identify Larix kaempferi as the most fire-resilient species among those tested, making it a promising material for use in timber structures. This work offers practical insights for improving fire safety in wooden buildings and supports the strategic use of Korean wood in sustainable and fire-safe architecture.

Carbon emissions accelerate global warming and climate change, prompting the global development of strategies for carbon reduction. Wood, with its excellent carbon storage capacity, is a sustainable and environmentally friendly material. One cubic meter of timber can absorb 1 t of carbon dioxide and store 250 kg of carbon. This study aimed to conduct fire resistance tests on structural glue-laminated timber beams made from Korean larch (Larix kaempferi) and analyze their char properties. The specimens were fabricated with different cross-sectional shapes and areas and underwent load-bearing fire resistance tests. The results were analyzed in terms of char depth, char rate, and changes in char thickness based on the aspect ratio of the beams. In the smaller specimens, the char properties were influenced more by the width than by the length of the beam. Additionally, at a constant cross-sectional area, charring was deeper when the width was shorter than the height. The specimens did not exhibit significant differences in displacement behavior, with all specimens displaying displacements below the maximum permissible value, indicating suitable fire resistance. The findings of this study provide a foundation for research and development of fire resistance design standards for wooden structures utilizing Korean timber.

As the carbon storage capacity of timber is recognized, there is growing interest in timber and wooden structures as a solution to various environmental problems. The use of Korean timber with substantial carbon storage capacity is required to reduce Korean carbon emissions and circulate timber resources. In this study, fire tests were conducted to investigate the charring properties of glued laminated timber columns made of Korean larch. The fire tests were conducted under both load-bearing and non-load-bearing conditions. The fire test results showed that the charring depth was affected by the corners of the section and that the load ratio had an insignificant influence on the charring depth when the load ratio was 0.9 or less. This study provides data that can be used to compare the charring properties of laminated wood produced using South Korean larch with the charring properties of foreign standards. This research provides reference data for developing fire-resistant design standards for timber structures made from South Korean timber.

As the carbon storage capacity of timber is recognized, there is growing interest in timber and wooden structures as a solution to various environmental problems. The use of Korean timber with substantial carbon storage capacity is required to reduce Korean carbon emissions and circulate timber resources. In this study, fire tests were conducted to investigate the charring properties of glued laminated timber columns made of Korean larch. The fire tests were conducted under both load-bearing and non-load-bearing conditions. The fire test results showed that the charring depth was affected by the corners of the section, and that the load ratio had an insignificant influence on the charring depth when the load ratio was 0.9 or less. This study provides data that can be used to compare the charring properties of laminated wood produced using South Korean larch with the charring properties of foreign standards. This provides reference data for developing fire-resistant design standards for timber structures made from South Korean timber.