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pressurisation schemes, are commonly used in office buildings in some parts of the world.

  • Piston effect due to movement of lift cars. While the use of lifts as a means of escape in the event of fire is generally discouraged, they do find use in transporting fire-fighters and disabled persons. Lifts cars generate strong suction pressures when in operation, which can interfere strongly with smoke management schemes that are intended to keep smoke out of the lift shaft. The problem is particularly acute with fast moving cars in single lift shafts. Design methods using pressure-differentials have been developed which account for this scenario [Klote & Tamura, 1986].

The above mechanisms are described comprehensively elsewhere [e.g.Tamura, 1994]. Each will produce pressures of varying magnitude, depending on the size of fire, the capacity of mechanical components, climatic/weather conditions and the geometry of the building, ducts, openings etc. Each may then play an important role in how the smoke moves and smoke management schemes function. The relative importance of each mechanism will depend on the individual smoke management scheme and the magnitude of the pressures generated.

Individual smoke management measures, that may be employed singly or in combination, are summarised below. Their use as part of an overall system to provide smoke protection for common access escape routes in residential premises is discussed. In general, a smoke management strategy for common access egress paths will comprise compartmentation (containment by physical barriers) plus one or more passive or active measures.

© Building Research Establishment Ltd 2005

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