definition
strict definition
pressurized stairwells
Interior stairways with an air pressure higher than the surroundings for fire safety.
A pressurized stairwell is an interior shaft in a structure holding one or more stairways, in which the air pressure is controlled and set to a level higher than the surrounding spaces in the structure. This is done to limit smoke entering stairwells, and to facilitate the safe evacuation of occupants in an emergency.
The controlled pressure in the stair shaft is higher than in adjacent spaces. The comparison is relative to those surroundings rather than a fixed pressure value in this definition.
The feature helps keep smoke out of the escape route. A shaft can contain one or several stairways without changing the pressure-control principle.
Related definitions
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access control system
Electronic systems which boost security by verifying the access rights of persons entering an area. -
aircraft warning lights
Small lights at the top or corners of a structure which increase its visibility to pilots. -
automatic fire doors
Doors which automatically keep an area sealed in order to prevent the spread of smoke or fire. -
baggage inspection at entry
Entrance checkpoints requiring inspection of incoming bags, with a possible minimum bag-size threshold. -
defibrillator
A defibrillator available to anyone at a place, capable of delivering an electrical shock for certain cardiac-arrest rhythms. -
emergency exits
At least one supplementary exit beyond regular entrances and exits, available for emergencies. -
external fire escape
A fixed external stairway, ladder, or slide providing an escape route from each occupiable floor to ground level. -
fire alarm system
An automated or user-activated system to detect fire and to alert occupants of a building. -
hand scanners at entry
Biometric entrance devices identifying people from stored hand measurements, used for security or attendance records. -
internal safety rooms
Rooms designed and designated as refuges for building occupants during an attack or other disaster. -
lightning protection
Special rods and pathways to channel lightning and protect a structure from a strike. -
metal detectors at entry
Apparatuses at the entrance which screen persons for metal objects being carried in. -
security alarm
An automated or user-activated system to warn off intruders or criminals and to alert police. -
security guard service
On-site security personnel available 24 hours a day, or at least during all hours of usage. -
sprinkler system
An automated system which emits water or other extinguishing agents in case of fire. -
vehicle warning lights
Lights fixed to an object to warn passing or approaching vehicles of its presence and reduce collision risk. -
video camera surveillance
One or more security cameras watching or recording activity at important points in or around a structure.