What type of material should fire dampers be constructed from in recirculating systems?

Fire dampers in recirculating systems must be constructed from a material that is consistent in gauge with the shell of the duct system. This is important to ensure structural integrity and proper functioning of the damper under fire conditions. The same gauge material allows the damper to effectively seal off the ductwork, preventing the spread of smoke and flames during a fire incident. Without this consistency in construction, the damper may not perform adequately, potentially compromising fire safety protocols.

Using low gauge metal or any type of metal may not provide the necessary strength and sealing ability when subjected to high temperatures. Thermal resistant glass, while useful in some applications, is not suitable for the construction of fire dampers in recirculating systems due to its fragility and lower effectiveness in fire containment compared to metal materials designed for such applications. Therefore, the correct choice reflects the need for durability and effectiveness in fire protection considerations outlined in the NFPA 96 standard.