Shaft enclosures of 4 stories or greater are fire-rated at how many hours?

Shaft enclosures that serve buildings of four stories or greater are required to have a two-hour fire-resistive rating. This rating is necessary to help contain a fire that may occur within the shaft and prevent it from spreading to other areas of the building. The two-hour rating provides sufficient time for occupants to evacuate safely and allows firefighters to control the fire before it can endanger other parts of the structure. Building codes are designed to ensure that fire compartments are effectively created to protect life safety and property, which is why maintaining a two-hour fire rating in shaft enclosures is critical for multi-story buildings.