If you're driving around the south side of downtown Friday and see a blazing high-rise, don't be alarmed.

That's because the Chicago Fire Department is conducting a revolutionary fire drill after purposely setting a vacant 16-story high rise ablaze to test a new way to fight fires.

It's the first time a test like this has been conducted anywhere in the United States, NBC 5's Lisa Tutman reported.

The CFD set fire to the third floor in a process they call Positive Pressure Ventilation, which is conducted by putting huge fans in the base of the stairwell.

"We're looking to create a greater pressure in the stairwell that we designate for evacuation and firefighting and what the fire itself is creating, so we can keep that stairwell clean," said Fire Commissioner Ray Orozco. "We're studying the phenomenon of wind-driven fires that have killed many civilians and firefighters, taking what firefighters have passed down as experience thru the years and creating a manual. This experiment will save lives."

Information from the burn will be gathered and shared with other fire departments across the country, where this kind of live burn has never been done.

Orozco said technology is key.

"We need to understand it and how to use it properly. If not, it can have disasterous results. Our No. 1 goal is to save lives, and that is what we're trying to do today."

Orozco said he and his crew saw temperatures drop in the hallways from 600 degrees to about 60 degrees.

"But then when the door closed, we saw them increase rapidly again, which forced the firefighters back down the hallway," he said.

It will go on most of the day near 51st and Federal and not impact traffic.