This study investigates the one-dimensional charring behavior of glued laminated timber (glulam) manufactured from Malagangai (Potoxylon melagangai) under standard fire exposure conditions. Specifically, the research evaluates the effectiveness of a fire-retardant coating in enhancing the fire resistance of glulam. The fire retardant used in this study is a waterborne, transparent formulation designed for application on both newly processed and preservative-treated timber surfaces, offering an additional layer of protection against fire. To assess the fire performance of both treated and untreated glulam specimens, a fire resistance test was conducted in accordance with ISO 834 (equivalent to BS 476: Part 20). The charring rate of the specimens was measured based on the guidelines outlined in EN 13381-7:2014. The experimental findings indicate that while the application of the fire-retardant coating provides some level of protection, its impact on reducing the charring rate is relatively minor. The treated glulam exhibited a charring rate of 0.58 mm/min, whereas the untreated specimen had a slightly higher charring rate of 0.63 mm/min. Both values are lower than the standard charring rate of 0.65 mm/min prescribed in Eurocode 5. These findings contribute to a better understanding of the fire performance of tropical hardwood-based glulam and highlight the need for further research into optimizing fire-retardant treatments to enhance the fire resistance.

One-dimensional charring rate, glue laminated (glulam) timber, fire test, Eurocode, tropical timber