IC-rated enclosures that are sealed and gasketed to prevent air leakage from the living area to the attic area are to be used.
Air Leakage
IECC 402.4.1 Building Thermal Envelope
The building thermal envelope will be durably sealed to limit air infiltration with caulk, gaskets, weather stripping or an air barrier material. This includes all exterior wall penetrations and sealant requirements for the exterior wall base plates and vertical wall intersections.