New York City Stair  Pressurization Testing

Stairways are Fire Escape Routes

Stairwells have better fire ratings than the rest of the building. In new buildings, stairs are entirely built of concrete. So people can get out when the rest of the building is on fire, as stairways don't burn.

Stairways Full of Smoke

Even if the stairways do not burn, they can still fill up with smoke very quickly as stairs can mimic chimney shafts. When smoke enters a stairway, it makes it harder to see and breathe as one tries to get away from a fire. It's essential to keep the smoke out of stairways to allows residents to escape and firefighters to battle the fire.

Open Doors

As people are escaping the fire, they have to open the door to the stairway. When the door is open, smoke rushes in and prevents the stairway from using later escapees.

Smoke Push Back

The idea behind the stair pressurization is that the stairway should have more pressure during a fire than the rest of the building. That way, when the doors open, the higher pressure in the stairwell pushes the smoke back onto the floor, keeping the escape route clear of smoke.