What happens to intumescent firestop materials when exposed to heat?

Intumescent firestop materials are designed specifically to respond to heat exposure by expanding. When they are subjected to high temperatures, such as those generated by a fire, these materials undergo a chemical reaction that causes them to swell significantly. This expansion creates a barrier that fills gaps and seals openings in fire-rated assemblies, thereby helping to prevent the passage of fire, smoke, and hot gases through these spaces.

This characteristic is crucial for maintaining the integrity of fire-rated walls and floors, as it enhances the overall firestop effectiveness during a fire event. The ability to expand allows these materials to adapt to the changing environment and maintain their protective qualities as conditions evolve. Therefore, the correct understanding of their behavior highlights the importance of using intumescent materials in firestop applications.