What type of assembly should flexible ducts and air connectors not pass through?

Flexible ducts and air connectors should not pass through a fire-resistance-rated assembly due to the critical role these assemblies play in controlling the spread of fire and smoke within a building. Fire-resistance-rated assemblies are designed to maintain their integrity for a specific period during a fire, effectively preventing flames and smoke from moving from one compartment to another.

Allowing flexible ducts to penetrate these assemblies could compromise their intended function because flexible ducts are generally not considered fire-rated. If a fire were to occur, the flames could easily travel through the ducts, bypassing the protective measures established by the fire-resistance-rated assembly. Therefore, the building code emphasizes that any penetrations through these assemblies must be carefully managed and typically must use materials and systems that are tested for fire performance in accordance with the relevant standards. This ensures that the fire-resistance-rated assembly continues to function as intended, maintaining the building's safety features in the event of a fire.