Through penetrations in horizontal assemblies must be protected by an approved system with what minimum F rating/T rating?

Horizontal assemblies are critical components of fire-rated construction, designed to prevent the spread of fire and smoke between different areas of a building. When there are penetrations, such as pipes or ducts, they create potential paths for fire and smoke to travel. Therefore, it is essential to protect these penetrations with an approved firestop system that meets specific performance standards.

The minimum F rating/T rating of 1 hour indicates that the firestop system can effectively contain a fire for a duration of one hour, preventing the passage of flames and limiting heat transfer through the penetrated assembly. This level of protection is often sufficient for many applications in commercial buildings, particularly when the risk of fire has been evaluated and determined to be manageable.

Higher ratings, such as 2 hours, 3 hours, or 4 hours, would be required in more demanding fire safety situations, typically where there is a higher occupancy, more hazardous materials, or other factors that increase the potential fire risk. However, for common scenarios encountered in standard commercial building inspections, a 1-hour rating is often acceptable, aligning with typical building code requirements.

This knowledge allows inspectors to identify whether the installed firestop systems are appropriate for the specific fire ratings required by building codes, ensuring that the integrity