What happens during a fire to a firestop collar?

A firestop collar is specifically designed to enhance the fire resistance of penetrations through walls or floors where pipes, particularly plastic pipes, pass through. When exposed to heat during a fire, the materials in a firestop collar react by expanding. This expansion is critical as it effectively seals the gaps around the pipes, preventing flames and smoke from spreading through these openings.

The design of the firestop collar allows it to create a barrier that limits the passage of fire, thereby improving the fire safety of the surrounding structures. This function is particularly important in maintaining the integrity of fire-rated walls and ceilings, thereby helping to contain fires and protect the occupants and property within the building.

The other options do not accurately reflect the intended functionality of a firestop collar. For instance, while some materials may melt in extreme heat, a firestop collar is engineered to activate and provide a crucial sealing effect rather than losing effectiveness by melting. The potential release of toxic fumes is not a function of the collar under fire conditions, as it is designed to protect against those very hazards. Therefore, the correct response highlights the essential role of the firestop collar in fire safety by confirming its expanding behavior to seal gaps and mitigate fire risk.