How big a bunker your household needs

Space

Each cube is 10 x 10 ft outside and about 9 ft 4 in square inside, with an 8 ft finished ceiling. A bunk cube by itself can hold four, but a household also needs an entry, a kitchen, a bath and somewhere to sit, so we plan two people per cube across the whole layout. That is how a CUBE 2 sleeps four and a CUBE 8 sleeps sixteen.

For a short stay of a few days, people can live closer than that. For weeks or months, they cannot do it well. Privacy, a place to exercise and a place to be alone matter more the longer the stay runs.

Air

People make heat, moisture and carbon dioxide. Oak Ridge National Laboratory shelter research found that roughly 1 cubic foot per minute (cfm) of outside air per person is needed even in cold weather, just to keep carbon dioxide in check. In hot weather the figure is about 40 cfm per person to keep the temperature rise to a couple of degrees. The ventilation system has to be sized for the full household in the hottest month, not the average one.

Water

Ready.gov guidance is one gallon per person per day for drinking and sanitation. A household of eight for 90 days needs 720 gallons before cooking, laundry or showers. Water storage is planned along with floor space, because tanks take room.

A quick sizing rule

• Count everyone who will actually come, including the relatives who do not have a plan.
• Divide by two for the number of cubes, and round up.
• Add a cube for each thing you want in its own room: utility, bath, decontamination, medical, gym.

Then drag those rooms onto a model in the 3D Builder and see the price.

Questions