What is the fire resistance rating of aluminum drop ceilings?

This question requires clarifying the difference between material fire performance and assembly fire resistance rating. Aluminum itself is a non-combustible material. According to standard fire tests like ASTM E84 (Standard Test Method for Surface Burning Characteristics of Building Materials), aluminum typically achieves a Class A rating, meaning it has very low flame spread and smoke development indexes. This is a significant safety benefit, as the ceiling panels themselves will not contribute fuel to a fire.

However, a "fire resistance rating" (e.g., 1-hour, 2-hour) refers to the ability of an entire construction assembly (like a floor/ceiling or roof/ceiling assembly) to contain a fire and prevent its passage for a specified duration, tested under standards like ASTM E119. A standard aluminum drop ceiling system (panels and grid) installed below a floor or roof structure does not inherently provide a fire resistance rating to that assembly.

To achieve a fire-rated ceiling assembly using aluminum panels, the entire system must be designed and tested for that purpose. This typically involves using specific fire-rated heavy-duty suspension grid systems, potentially special hold-down clips for the panels, fire-rated insulation above the ceiling, and compliance with specific installation details outlined in tested assembly designs (e.g., UL/ULC listed designs). The aluminum panels become one component within that rated assembly. Therefore, while our aluminum panels are non-combustible (Class A), achieving an hourly fire resistance rating requires specifying and correctly installing a complete fire-rated ceiling assembly system.