What is a typical characteristic of intumescent firestop materials?

Intumescent firestop materials are specifically designed to expand significantly when exposed to heat, particularly during a fire. This expansion creates a barrier that helps to seal openings and joints, effectively slowing the spread of fire and smoke. The material reacts to high temperatures by swelling up, which fills the gaps and voids in fire-resistive assemblies, thereby maintaining the integrity of fire-rated walls or floors.

By expanding, these materials can adapt to the changes in their environment, providing an effective means of passive fire protection. The focus on thermal response is critical in understanding how firestop systems function during a fire scenario. This characteristic distinguishes intumescent firestop products from other types that may have different properties or functions, such as simply absorbing heat without providing that essential barrier effect.