What is a key property of elastomeric materials in firestop systems?

Elastomeric materials are valued in firestop systems primarily for their ability to absorb and dissipate heat, which plays a crucial role in preventing the propagation of temperatures to the other side of a fire barrier. This property is vital because, during a fire, the integrity of the barrier must be maintained to prevent the spread of flames and smoke through openings, joints, and penetrations in walls, floors, and ceilings.

The absorption of heat by elastomeric materials contributes to maintaining a lower temperature on the protected side, thereby enhancing safety and compliance with fire safety codes. This aspect also underscores the materials' role in delaying the rise in temperature, contributing to the overall effectiveness and reliability of firestop systems.

In contrast, other options imply properties that do not align with the intended function of elastomeric materials in firestop systems. For instance, materials that expand significantly may not always maintain proper sealing once expanded, which can compromise the barrier. The idea of materials igniting quickly is counterproductive to firestop performance, while resistance to moisture and chemical reactions, while useful in some contexts, is not specifically a defining characteristic of their fire-resistance capabilities.