What factor significantly influences firestop performance during high temperatures?

The significant influence of thermal expansion characteristics on firestop performance during high temperatures lies in how materials react under heat. When exposed to high temperatures, firestop materials may expand, contract, or change their physical properties. Effective firestop systems must account for these changes to maintain their integrity and provide reliable protection against the spread of fire and smoke.

Materials that have been engineered to withstand thermal expansion will perform better in a fire scenario by maintaining a seal that prevents fire from breaching through the openings they protect. This characteristic ensures that the firestop can adapt to temperature fluctuations without compromising its ability to contain fire or smoke, thereby enhancing overall safety and performance.

While the other factors listed may have some relevance in specific contexts, they do not carry the same weight in terms of materials' ability to perform under fire conditions as the thermal expansion characteristics do. Hence, focusing on the properties of the materials themselves is crucial in assessing firestop system effectiveness.