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

In the context of aircraft-related occupancies, the requirement for exterior walls to have a minimum fire-resistance rating is driven by fire safety and protection measures to mitigate the potential spread of fire, especially in areas where aircraft are present. The determination that exterior walls located less than 35 feet from the lot lines must have a 2-hour fire-resistance rating is based on established fire codes designed to safeguard not only the structure itself but also neighboring properties and the safety of individuals nearby.

A 2-hour fire-resistance rating signifies that the wall can withstand fire exposure for two hours without collapsing or allowing flames to penetrate, thus providing ample time for occupants to evacuate and for firefighting efforts to begin. This requirement takes into account the increased hazard associated with aircraft-related operations, where flammable materials and large fuel sources could lead to intense fires.

While other distances like 25, 45, and 55 feet are significant, they do not meet the specific requirement set for aircraft-related occupancies, making 35 feet the threshold for the 2-hour rating in this context. This ensures both compliance with safety regulations and enhanced fire protection in sensitive environments.