For aircraft-related occupancies, exterior walls that are less than how many feet from lot lines must have a fire-resistance rating of 2 hours?

The requirement that exterior walls for aircraft-related occupancies must have a fire-resistance rating of 2 hours when they are less than 30 feet from lot lines is rooted in fire safety regulations designed to protect adjacent properties and minimize the risk of fire spread.

In the context of aircraft operations, buildings can be at risk for larger-scale fire hazards due to the presence of aviation fuels and equipment. The reason for the 2-hour fire-resistance rating is to ensure that if a fire were to start within the building, it would provide adequate time for emergency responders to act and for occupants to evacuate, while also protecting nearby structures from the risk of fire spread.

The specified distance of 30 feet is critical as it delineates the zone where the risk of fire spread is deemed significant enough to necessitate enhanced fire-resistance features in building design. Such regulations help in maintaining public safety and ensuring that the infrastructure surrounding aircraft-related facilities adheres to strict fire prevention and protection standards.