How is the fire-resistance of nonsymmetrical interior walls determined?

When determining the fire-resistance of nonsymmetrical interior walls, the focus is on how well the wall can withstand fire exposure from different sides. The correct approach is to consider the shortest duration obtained from testing both faces. This is because a nonsymmetrical wall may exhibit varying fire-resistance characteristics depending on which face is exposed to the fire. The fire-resistance rating is set by the weaker side, as it will fail first in a fire event. Thus, taking the shortest duration ensures that the wall meets safety codes and standards for fire performance.

Testing both faces independently provides insight into their respective fire-resistance qualities. However, the governing rating remains the lower rating, ensuring safety across scenarios where one side could be exposed more directly to heat and flames than the other. This methodology highlights the importance of identifying potential vulnerabilities in building materials, ultimately guiding better safety practices in construction and inspection.