When must a motor-vehicle-related occupancy provide a smokeproof enclosure for stairways?

A smokeproof enclosure for stairways in a motor-vehicle-related occupancy is required when there is a height difference of more than 30 feet between levels. This requirement is based on safety regulations designed to protect occupants during an emergency, particularly in the event of a fire.

The purpose of a smokeproof enclosure is to ensure that smoke and toxic gases do not travel through the stairways, which are vital for safe egress in emergencies. By establishing this height threshold, the regulation aims to mitigate the risks associated with smoke inhalation and provide a safer route for evacuation.

The other height options do not align with the established safety codes, which stipulate the need for smokeproof enclosures specifically at the 30-foot mark. Therefore, the legislation focuses on this height to ensure that buildings can maintain a safe environment, particularly in settings where motor vehicles, which can contribute to unique fire hazards, are present.