Does an "F" rating (fire) without an "FT" rating (fire and temperature) make a firestop system acceptable?
North American Building Codes generally state that all firestop assemblies penetrating a firewall or horizontal fire separation, in order to meet code, must have an "FT" rating not less than the fire-resistance rating for the fire separation.
If a firestop system has an "F" rating of 2 hours and a "T" rating of 15 minutes, this assembley has an "FT" rating of 15 minutes... not 2 hours. The "F" and "T" ratings are not separable. The ratings are expressed as the lowest of both the "F" and "T" ratings.