For Class I and II smoke dampers, what is the minimum required elevated temperature rating?

The minimum required elevated temperature rating for Class I and II smoke dampers is 250°F. This specification is critical because it ensures that these safety devices function effectively during a fire, maintaining their integrity and performance under elevated temperatures that can occur in a fire scenario.

Class I smoke dampers are designed for areas where smoke containment is a priority, while Class II dampers are used in more general environments, but both classifications require robust performance in the face of heat to prevent smoke spread and aid in the overall fire safety of the building.

Setting the temperature rating at 250°F provides a margin that helps ensure the dampers will remain operable during significant fire conditions, thereby enhancing the safety of building occupants and the effectiveness of the fire protection system. Lower temperature ratings, such as those listed in the other options, would not meet the necessary safety standards for these types of dampers.