Emergency bulkheads were areas of starships and space stations that could be utilized to isolate areas that had suffered damage.
In 2383, Ro Laren ordered the emergency bulkheads of Deep Space 9 to be closed prior to the destruction of the station due to Andorian sabotage and an attack by rogue Typhon Pact elements. Julian Bashir survived by taking refuge in an emergency bulkhead, as did Kira Nerys and Kasidy Yates. Their emergency bulkhead was in a section of wreckage from the station that entered the Bajoran wormhole and was recovered in the Gamma Quadrant by the USS Enterprise. (ST - Typhon Pact novels: Plagues of Night, Raise the Dawn)