What is the size of the door opening?

• A. Door 3 ft x 6.5 ft
• B. Door 2 ft x 6 ft
• C. Door 3 ft x 7 ft
• D. Door 3 ft x 6 ft

Answer: (A)

Door openings must provide enough clearance for a Marine in full gear to pass through safely and comfortably. A width of three feet gives ample shoulder and equipment clearance without being wasteful on space. A height of six and a half feet offers about 78 inches of vertical room, which accommodates most personnel wearing helmets and packs without needing to duck or risk head contact.

The other options fall short in practical use: a door only two feet wide is too narrow for gear and personnel to pass smoothly; a height of seven feet is more than necessary and uses more space than needed; a height of six feet can be restrictive for taller individuals and helmets, increasing the chance of contact.

Therefore, the size that best fits typical Marine passage needs is three feet by six and a half feet.