In the context of duct penetrations, what must be installed at the floor line in specific cases according to code?

In the context of duct penetrations, a ceiling radiation damper must be installed at the floor line in specific cases to ensure that fire and smoke do not pass through openings in floors or ceilings where ducts are installed. The primary function of a ceiling radiation damper is to restrict the flow of heat and smoke between different floors during a fire, helping to maintain the integrity of the building's fire-resistance-rated assemblies.

When ducts penetrate through ceilings that are part of fire-rated assembly, the installation of ceiling radiation dampers provides critical protection. They automatically close when exposed to elevated temperatures, which can occur during a fire, thereby preventing hot gases and flames from spreading into the concealed spaces or other floors above. This is particularly important in commercial buildings where ductwork often connects multiple floors and might carry smoke or hot gases throughout the system, exacerbating a fire situation.

This requirement ensures that safety measures are in place to protect the occupants and limit property damage during a fire event.