A one-hour fire test was conducted independently at the Southwest Research Institute in San Antonio, Texas. Hollow brick was tested alongside vinyl siding and fiber cement in typical residential exterior wall sections.
Vinyl siding burned after only 18 minutes. Fiber cement, which outperforms wood and vinyl siding, failed in under an hour. The clay brick passed.
The study showed that clay brick cladding provides a minimum one-hour fire resistance rating alone. Other exterior cladding materials need to incorporate other fire-resistant materials in their wall systems to achieve this rating when tested in accordance with American Society of Testing and Materials (ASTM) E119, Standard Test Methods for Fire Tests of Building Construction and Materials as recognized by the International Building Code (IBC).
Made from abundant natural materials, fired-clay brick is free of volatile compounds that will not burn, melt, or combust.
“Brick’s inherent fire resistance consistently outperforms other home and building exteriors and can also reduce property damage,” said Ray Leonhard, president and CEO, the Brick Industry Association (BIA).
Each wall clad in a different material was subjected to fire for one hour or until it succumbed to one of the failure criteria—the wall collapsed, flame or hot gas penetrated the wall, or the temperature rose more than 121 C (250 F) on the unexposed (interior) side.
Firefighters reported that it takes about one and a half hours for a fire to breach a brick home, compared to fiber cement in under an hour and vinyl siding in minutes.
Fire resistance can also be achieved using thin brick. Independent testing reports show that a wall assembly with thin brick veneer thin set into polymer modified mortar provides a one-hour fire resistance rating on both the exterior and interior sides of the wall when tested in accordance with ASTM E119.