How many feet must one hangar door be opened, and what is the purpose?

The correct choice indicates that a hangar door must be opened 50 feet primarily for ventilation and access for Civilian Fire Rescue (CFR) vehicles. This width is essential to ensure proper airflow within the hangar, which can be crucial for safety and operational efficiency. Adequate ventilation helps dissipate any potentially harmful fumes or heat buildup, creating a safer environment for personnel and equipment.

Additionally, maintaining a 50-foot opening allows for unhindered access for CFR vehicles in case of emergencies. It ensures that these vehicles can quickly and effectively enter or exit the hangar to respond to situations that may require immediate action, such as fires or other emergencies.

This requirement is part of standard safety protocols designed to protect personnel and equipment in the hangar, emphasizing the importance of maintaining both accessibility and safety in operational environments.