Through penetrations in concrete floor assemblies can have the annular space filled with mortar provided that the penetrating item is what?

The correct response highlights that the penetrating item must be a metallic pipe for the annular space around it in concrete floor assemblies to be filled with mortar. This requirement is rooted in fire safety and the maintenance of structural integrity within building codes. Typically, metallic pipes provide a reliable barrier against fire spread and smoke while also ensuring that the material surrounding the penetration can maintain its integrity in the event of a fire.

Metal pipes do not degrade the same way non-metallic materials might, and they can withstand higher temperatures without collapsing. Filling the annular space around these pipes with mortar helps provide additional fire resistance, which is crucial in safeguarding the building and its occupants.

In contrast, non-metallic pipes, plastic conduits, and wooden beams might not meet the same stringent requirements for long-term durability or fire resistance. Using mortar in these cases could potentially lead to issues such as a compromised seal, which could allow smoke and fire to spread more easily. Thus, regulations specify that only metallic pipes in these scenarios can have their surrounding space filled with mortar.