How does a firestop collar functioning during a fire?

The correct choice centers on the function of a firestop collar, which is specifically designed to provide a protective seal around plastic pipes that pass through fire-rated walls or floors. In the event of a fire, the collar expands due to the heat, forming a physical barrier that seals any openings. This expansion is crucial, as it helps to prevent flames and hot gases from traveling through these openings, thereby maintaining the fire-resistance rating of the structure.

This method of sealing is particularly critical in modern construction, where plastic pipes are often used. Firestop collars are essential components in firestopping systems, contributing to overall fire safety by minimizing the potential for fire spread through penetrations in fire-rated assemblies.