For example, in the Delaware talk, Dr. Thornton contrasted the lightly protected, wallboard-encased stairwells of the World Trade Center -- which were severed by flying debris, trapping hundreds of people above -- with the thick concrete walls enclosing the Petronas stairwells.
But the trade-center stairwells were protected by the more delicate gypsum.
While the building's façade and its stairwells are protected as historical monuments, the interior walls are fair game for destruction or adaptation, depending on the needs of the works and the impulses of the artists, said Paolo Stolpmann, one of several art students who work in the gallery.
Rough sleepers and drug addicts found their way into the indoor stairwells, which have never been protected by entryphones, and into the poorly maintained residential floors beyond.
The stairwell was blocked from above — not by fire or structural steel, but by huge pieces of the light gypsum drywall, often called Sheetrock, that had enclosed the stairwell to protect it.
The stairwell was blocked from above -- not by fire or structural steel, but by huge pieces of the light gypsum drywall, often called Sheetrock, that had enclosed the stairwell to protect it.
Regularly checking emails, Facebook and news sites, I worried about my tribe, my people including family, good friends and colleagues sent running, with fifteen seconds of warning, to bomb shelters, basements and stairwells to protect themselves from Hamas's indiscriminate firing of hundreds of rockets.
After our failed evacuation, most of the people in the fire escape stairwell and many staff members who attempted to protect the guests were shot and killed.
The new attention to potential disasters may also have an effect on the basic shapes of buildings, as designers seek to protect the vital core of the structure, which contains the elevators, stairwells and utility lines.
There were security issues that called for fortified stairwells, blast-resistant glass and an impregnable concrete base to protect the building from street-level attacks.
Mr. Prendergast suggested that aboveground floodwall panels, to be placed over station stairwells or sidewalk vents, were seen as a leading option to protect the system.
