What is the approved construction material for the masonry fireplace liner?

The approved construction material for a masonry fireplace liner is noncombustible material. This is essential because fireplace liners serve as a protective barrier that guides smoke and combustion gases safely up the chimney while also preventing heat transfer to combustible materials in the structure. Noncombustible materials, such as clay tile or stone, are specifically designed to withstand high temperatures without igniting, thereby ensuring the safety and efficiency of the fireplace system.

When considering other options, brick and mortar may not meet the specific standards for liners, as they can absorb moisture and may not perform as effectively in terms of thermal performance. Concrete blocks could also be inappropriate due to their potential combustibility and moisture issues, which can lead to damage or reduced effectiveness over time. Wood and clay, while commonly found in construction, are not suitable as they lack the necessary resistance to heat needed in fireplace applications, with wood being inherently combustible. Therefore, using noncombustible materials ensures the safety and functionality of the masonry fireplace.