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Evaluation of Fire Service Positive Pressure Ventilation Tactics on High-Rise Buildings.


pdf icon Evaluation of Fire Service Positive Pressure Ventilation Tactics on High-Rise Buildings. (19616 K)
Kerber, S.

Volume 2;

Interflam 2007. (Interflam '07). International Interflam Conference, 11th Proceedings. Volume 2. September 3-5, 2007, London, England, 1289-1300 pp, 2007.

Keywords:

smoke movement; fire departments; ventilation; high rise buildings; NFPA 92A; pressure differential; smoke barriers; experiments; fans; structures; pressure; fuel load; smoke; stairwells; fire fighters; effectiveness; fuel load

Abstract:

Positive Pressure Ventilation (PPV) is a ventilation technique used by the fire service to remove smoke, heat and other combustion products from a structure. This allows the fire service to perform tasks in a more tenable environment. PPV fans are commonly powered with an electric or gasoline engine and range in diameter from 0.30 m to 0.91 m (12 in to 36 in). More recently fans up to 2.1 m (84 in) have been manufactured and mounted on trucks and trailers. Typically, a PPV fan is placed about 1.2 m to 3.0 m (4 ft to 10 ft) outside the doorway of the structure. It is positioned so that the "cone of air" produced by the fan extends beyond the boundaries of the opening. With the doorway within the cone of air, pressure inside the structure increases. An exhaust opening in the structure, such as an opening in the roof or an open window, allows the air to escape due to the difference between the inside and outside air pressure. The smoke, heat and other combustion products are pushed out of the structure and replaced with ambient air. Another use of PPV is to increase the pressure in a portion of a structure by not providing a vent location. This increase in pressure, if adequate, will prevent smoke flow to a "protected" area. This is most useful in larger structures such as schools, hospitals and high-rise buildings. In a high-rise building it is possible to increase the pressure of a stairwell to prevent the infiltration of smoke if the fans are properly configured. Two sets of experiments were conducted in high-rise buildings to analyze the impact of fire service PPV tactics.