Interior Location: Whichever space you choose should have a minimal number of windows (preferably none) and doors. Make sure it offers the opportunity to shut off outdoor air exchange, at least for a short period of time, explains Scott Tezak, practice lead for security and emergency preparedness at TRC Companies Inc., a national engineering, consulting, and construction management firm.
If necessary, choose several rooms to avoid overcrowding, such as large storage closets, utility rooms, pantries, copy areas, and conference rooms without exterior windows. Do not shelter in rooms with mechanical equipment – you may not be able to seal these areas from the outdoors very well.
Chemical or radiological releases may necessitate a backup plan, warns the Centers for Disease Control & Prevention (CDC). Rooms above ground level are best for chemical spills because some chemicals are heavier than air and could sink. However, a release of radioactive particles would make a centrally located room or basement the better option. “Access to bathrooms is a plus,” the CDC notes.
The Right Size: “Many times you want a large internal area, but not the largest area of the building,” says Tezak. “A large area helps you congregate people in one space where it’s easier to control the crowd, but the largest may have structural considerations you need to be aware of.”
The CDC recommends 10 square feet of floor space per person to prevent carbon dioxide buildup for up to five hours. However, the sheltering period may be shorter than that in the event of a chemical, biological, or radiological release, the organization notes in its official shelter in place guidance: “Local officials are unlikely to recommend the public shelter in a sealed room for more than two to three hours because the effectiveness of such sheltering diminishes with time as contaminated outside air gradually seeps into the shelter.”
Pre-Equipped: Ideal shelter spaces have hard-wired telephones, as cellular networks can be damaged or overwhelmed during emergencies. You will need phone access to call emergency contacts and report any life-threatening conditions that occur while sheltering. Make backup plans for VoIP networks, as they can be disabled if the power goes out.
The rooms should also have radios or TVs – consider keeping some battery-powered radios in your disaster kit in case the power goes out.