What feature do intumescent firestop products generally offer?

Intumescent firestop products are specifically designed to react to high temperatures by expanding significantly. When exposed to heat or flames, these materials undergo a chemical reaction that causes them to swell and increase in volume, effectively sealing openings and preventing the passage of smoke, fire, and gases. This expansion creates a barrier that can help protect structural elements and improve the overall fire-resistance of a building.

While other characteristics such as chemical resistance, waterproof properties, and flexibility at low temperatures may be beneficial in specific situations, they are not the primary function of intumescent firestop products. The ability to increase in volume when heated is what distinguishes these materials in firestop applications, making them essential for maintaining fire safety standards in buildings and construction projects.