What is a common mineral fiber backing material used in firestop systems?

Mineral wool is a common backing material used in firestop systems due to its excellent fire-resistant properties. It is made from natural or synthetic minerals and is designed to withstand high temperatures, making it effective in preventing the spread of fire and smoke through openings and joints in fire-rated constructions. Mineral wool effectively insulates and provides structural support in firestop applications, ensuring that firestop systems maintain their integrity under extreme conditions. This characteristic is crucial for compliance with building codes and ensuring occupant safety in the event of a fire.

While materials like fiberglass also have certain fire-resistant qualities, mineral wool is specifically distinguished for its superior performance in high-temperature scenarios typically encountered in firestop applications, making it the preferred choice in many situations.