Cities should update fire standards for skyscrapers in light of the World Trade Center (search) collapse and develop new materials that can better protect tall buildings in an inferno, investigators said Thursday.

Engineers with the National Institute of Standards and Technology (search) also urged installation of "fire-protected and structurally hardened elevators" to impror fire doesn't bring down the entire structure.

The report calls for "the development and evaluation of new fire resistive coating materials, systems and technologies with significantly enhanced performance and durability to provide protection following major events."

Sunder also urged managers of older high-rises to consider whether the recommendations for new codes and practices would make their buildings safer, too.

"Building owners and public officials should look at these recommendations in light of the inventory of existing buildings and take steps to mitigate any unwarranted risks," he said.

The investigation considered a number of what-if scenarios, some hopeful, some terrifying.

The NIST has determined that if the building had been struck later in the day at full occupancy, some 14,000 people may have died.

But if the buildings' elevators had been better protected, many of them would have remained functional after the attacks, Sunder said. Those elevators could have helped more people escape the building before the collapse, or deliver firefighters quickly to the inferno and perhaps rescue those trapped above.

The agency's report also examined emergency response efforts after the attack. It concluded that some of the 2,749 lives lost at the World Trade Center might have been saved with stronger evacuation systems and better communication among rescuers.

Emergency workers need to change how they coordinate rescue efforts, the investigators concluded. The report recommended that much of the intelligence-gathering and decision-making done onsite during such rescue efforts should be transmitted outside the building; it suggested keeping a "black box," like the ones in airplanes, to record critical information for study after a major incident.

On Sept. 11, the New York City fire department located its command centers in the buildings' lobbies.