Which assembly rating reflects the hours a firestop assembly will not exceed a set temperature?

The assembly rating that reflects the hours a firestop assembly will not exceed a set temperature is known as the (T) rating. This rating specifically measures the temperature rise allowed on the unexposed surface of a firestop assembly during a fire resistance test. It indicates how long the assembly can maintain a limited temperature increase, which is crucial for ensuring that the materials behind the firestop do not ignite or fail due to excessive heat.

In fire protection, understanding these ratings is vital for adhering to safety codes and ensuring that firestop systems function as intended in preventing the spread of fire and smoke. The (T) rating helps determine the effectiveness of the firestop in protecting structural and occupant safety over the duration of a fire event in terms of thermal performance.