High-Temperature Resistance: The primary characteristic of fire bricks is their ability to endure high heat. They can withstand temperatures ranging from 1,500°F (815°C) to over 3,200°F (1,760°C), depending on their composition and grade.
Low Thermal Conductivity: Fire bricks act as excellent insulators. Their low thermal conductivity means they don't transfer heat easily, which helps to contain heat within a structure and improves energy efficiency. This is crucial for applications like furnaces and kilns, where it's important to keep the heat where it's needed.