When installing ENT through a fire-resistive floor, what must be done to maintain the fire resistance rating?

To maintain the fire resistance rating when installing Electrical Nonmetallic Tubing (ENT) through a fire-resistive floor, it is essential to use firestopping methods that are approved. Firestopping involves sealing the penetration created by the ENT to prevent the passage of fire, smoke, and heat from one side of the fire-resistive assembly to the other.

This is critical because fire-resistive assemblies are designed to withstand fire for a specified period, and any penetration for wiring or piping can compromise that integrity. Approved firestopping materials and methods ensure that the seal created meets the necessary standards for maintaining the properties of the fire barriers.

Covering with non-flammable materials, exclusively using insulated fittings, or running ENT through a separate conduit may have their own benefits in specific contexts, but they do not directly address the need to seal a penetration to maintain the fire resistance rating as effectively as firestopping does. Thus, utilizing approved firestopping methods is the most effective and recognized requirement for ensuring that the fire resistance rating of the floor assembly is maintained during installation.