RALEIGH, N.C. (WNCN) – When firefighters are trapped in wildfires, their odds of survival can be largely dependent on their equipment.

North Carolina State University researchers developed four new designs for shelters to protect firefighters trapped in wildfires. They believe these prototypes could increase the survival time inside the shelter compared to currently available shelters.

Researchers found in lab simulations of wildfire burn-overs, temperatures inside their shelters remained within survival limits for longer, and the shelters took longer to break open.

“For the wildland firefighter, deploying a shelter is the last thing they want to do – it’s the final resort, the last line of defense,” said study co-author Roger Barker, the Burlington Distinguished Professor of Textile Technology at N.C. State and the director of the Textile Protection and Comfort Center.

Barker said there was no such thing as “fire-proof.”

“What we’re trying to do is to buy more time. We were able to demonstrate our shelters could increase the time to failure – time that could be critical for survival,” Barker said.

Researchers said the problem with standard fire shelters is their aluminum outer layer. That material melts when in contact with direct flame. So, they worked to develop a better inner heat-blocking barrier and additional thermal insulation into the shelter.

“We know we can make a better shelter,” said the study’s lead author Joseph Roise, professor of forestry and environmental resources at N.C. State.

The team constructed four prototypes, two of which weighed less than five pounds.

In the lab, those designs were hit with direct flame for 60 seconds.

Researchers then measured how long it took the temperature at the floor of the shelters to reach 302 degrees Fahrenheit – the temperature threshold for survival.

Cameras were set up inside to see when the inner layer of the shelters would break open.

Researchers found all of the prototypes outperformed the currently available fire shelters.

Researchers hope their lab and field tests can help develop new and better shelters while also improving shelter testing.