What type of assembly rating does firestopping aim to restore?

Firestopping primarily aims to restore the hourly rating of a rated assembly, which is crucial for maintaining the fire-resistance capabilities of various building elements. When a penetration occurs in a fire-rated barrier—such as walls, floors, or ceilings—proper firestopping materials and methods are implemented to ensure that the assembly can still withstand fire exposure for the intended duration, often specified by code or design.

The hourly rating helps to determine how long the assembly can resist the spread of fire and smoke, which is essential for protecting life safety and property. Firestop systems are tested and classified to meet these ratings, and using them correctly allows structures to comply with safety regulations and reduce the risk of fire-related incidents.

In contrast, architectural assembly ratings and structural assembly ratings do not directly pertain to the fire-resistance aspects that firestopping specifically targets, while environmental ratings are unrelated to the construction and fire-rated performance of assemblies.