In the case of a fire, glulam is a more resistant construction material than unprotected steel. The burning wooden components become covered with a layer of charcoal, which protects the core of the structure due to its low thermal conductivity. The combustibility of glulam is estimated at an average of approx. 0.7 mm per minute.
After 30 minutes the girth of the glulam components’ each side decreases by approx. 20 mm and 40 mm after 60 minutes. The remaining glulam can still hold the load in such a situation.
Glulam without any additional fire protection can obtain the F 30 or F 60 fire resistance class.