The invention relates to a device for developing an aircraft hold located under the floor of the passenger cabin and the cockpit and including a so-called commercial area in which freight can be transported and a technical area including technical equipment and located at the front of the commercial area an at least partially under the cockpit, wherein said device includes: at least one compartment sealed relative to the hold located at the front of said commercial area and at the back of a portion at least of the technical area; a staircase connecting each compartment to a portion of the intermediate floor between the passenger cabin and the cockpit; and a sealed corridor extending from said staircase to each of said sealed compartments.