Which material is known for expanding when exposed to heat for firestop applications?

The material known for expanding when exposed to heat for firestop applications is intumescent seals. These seals are specifically designed to swell significantly when subjected to high temperatures, creating a robust barrier by filling gaps and preventing the passage of flames, smoke, and hot gases during a fire. This expansion capability makes intumescent seals particularly effective in maintaining the integrity of fire-rated walls and floors, which is crucial for life safety and property protection.

In firestop systems, the use of intumescent materials is crucial as they adapt to extreme conditions, providing enhanced fire resistance over time as the fire situation evolves. Understanding this property helps in selecting the appropriate firestop solution based on the specific requirements of the application.