What aspect does a curtain wall system test focus on during fire resistance evaluations?

In fire resistance evaluations, a curtain wall system test particularly emphasizes the perimeter connection with rated floors. This is crucial because the connection points between the curtain wall and the structural components, like floors, can be vulnerable areas during a fire. The rated floor typically has specific fire-resistance ratings to prevent the spread of fire and ensure that it protects occupants and structural integrity for a designated period.

Testing this aspect assesses how effectively the curtain wall maintains its fire resistance under exposure to flames and heat, especially at these connecting joints. Proper design and installation of perimeter connections are essential since they can either contain the fire within a specific area or allow it to spread through the building.

In contrast, other options focus on different elements of a wall system. While structural integrity is important, the fire resistance evaluation specifically investigates how these connections react under fire rather than the overall strength of the wall. Insulation properties address thermal performance but don't directly pertain to fire resistance testing. Fireproofing applied to surfaces is necessary, but again, this does not capture the critical interaction at perimeter connections during a fire scenario.