According to the American Red Cross, a mega shelter is a building or other structure assessed and certified to be used as a secure place prior to, during, and after a disaster. In such times, a mega shelter resembles a small city, one in which thousands of affected people centralize for the most efficient distribution of humanitarian aid and life-support services.
Because of the importance of mega shelters, such facilities must meet certain requirements for certification. A centralized communications system is required so that safety officials and aid managers can streamline logistics and ensure the safety of the displaced people inside the shelter. In addition, mega shelters must ensure stable infrastructure, such as systems controlling water, sewage, and electricity, to accommodate a large and growing body of people for an indeterminate length of time. Mega shelter classification also requires the building owners or operators to provide a policy document that specifically outlines the leadership organization and chain of command in a disaster.