Unconcealed vertical openings are allowed if they connect a maximum of how many stories?

Unconcealed vertical openings refer to vertical shafts, such as stairwells or elevator shafts, that connect different levels of a building. The code typically allows these openings to connect a limited number of stories to ensure the safety of the building's occupants and facilitate fire containment. When built correctly, with appropriate fire-resistive construction and protective features, vertical openings that connect up to four stories help maintain necessary fire separations and exit accessibility without compromising safety.

Allowing these openings for up to four stories strikes a balance between architectural design flexibility and maintaining the integrity of fire protection measures. By restricting the connection to this number of stories, building codes help ensure that safety features like fire alarms, suppression systems, and escape routes remain effective.