New York Downtown Hospital has fully re-opened, while a handful of other hospitals remain closed, following severe storm damage last week.

Downtown evacuated its patients before Sandy arrived, at the urging of city and state health officials. Other hospitals in vulnerable areas stood their ground—only to evacuate patients during or shortly after the storm, when their backup systems failed.

Like all hospitals, Downtown has backup power, but Chief Executive Officer Jeffrey Menkes said remaining open was never an option, once Consolidated Edison preemptively shut down both the electricity and steam systems in the area.

“We do have a backup generator, but to not have steam service, if the grid went down in lower Manhattan, meant that we wouldn’t have heat and we wouldn’t have hot water,” he said. “We really wouldn’t be able to function as a normal hospital.”

Downtown is close to the Brooklyn Bridge and the South Street Seaport, but it’s actually relatively high—20 feet above sea level. That puts it in the Evacuation Zone C, with very little chance Sandy would inflict flooding. In the end, the only damage Downtown sustained was broken glass falling in its plaza from adjacent buildings.

Meanwhile, New York University, Bellevue, Coney Island, and the Manhattan Veterans Administration hospitals all suffered enough damage that they show no sign of reopening soon.

But even though Downtown was relatively unscathed, it still took 10 days to re-open, because Consolidated Edison had not restarted its steam supply.

Menkes said the shutdowns suggest all hospitals should reevaluate how they protect themselves from the elements and keep the lights on. Much attention has been focused on generators, electrical systems and flood-proofing, he said, but beefing up those things up don’t help if you lose the steam you rely on for heating and cooling.

“Hospitals should not be connected, electrically or by the steam system, to the general community,” he said.

Instead, Menkes believes, hospitals should have their own dedicated grid or the ability to switch to another grid in the event of emergency—or maybe even have their own mini electricity-and-steam-producing plants, known as co-generation facilites.

“We need our hospitals to function in any catastrophic event,” he said.