What characteristic do firestop pillows possess?

Firestop pillows are designed to be intumescent, which means they have the ability to expand when exposed to heat or fire. This expansion helps to create a barrier that prevents the spread of fire and smoke through openings or penetrations in fire-rated walls, floors, and ceilings. The intumescent properties of these pillows allow them to effectively seal any gaps created by cables or pipes, significantly enhancing the fire containment effectiveness of the assembly.

While soundproofing materials may offer some noise reduction, it is not the primary function of firestop pillows. Their main purpose is to provide fire protection. Regarding electrical applications, although firestop pillows can be used in such contexts due to their adaptable nature, they are not limited to that use alone. Additionally, firestop pillows can often be reused in certain situations, depending on the guidelines and conditions of the installation, which contrasts with the notion that they cannot be reused once installed. Therefore, the characteristic that makes firestop pillows particularly valuable is their intumescent quality, which plays a crucial role in fire safety.