What is the minimum fire-resistance rating required for automatic shutters in escalator vertical openings?

The minimum fire-resistance rating required for automatic shutters in escalator vertical openings is 1.5 hours. This rating is crucial as it ensures that the fire shutter can withstand heat and prevent the spread of fire between different floors for an adequate amount of time during an emergency. By achieving this rating, the shutter serves as a critical barrier, allowing occupants more time to evacuate and aiding firefighters in their efforts to control the blaze.

The specific fire-resistance rating is often dictated by code requirements focused on life safety, property protection, and overall building design. A 1.5-hour rating reflects a balance between providing adequate protection and adhering to practical building standards. The higher ratings of 2 hours or more, while offering potentially greater protection, are typically reserved for more critical areas or applications where the conditions are deemed to be more severe. This ensures that building materials and construction methods align effectively with safety regulations and the specific use of the structure.