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Hazards Due to Smoke Migration Through Elevator Shafts. Volume 1. Analysis and Discussion. Final Report.


pdf icon Hazards Due to Smoke Migration Through Elevator Shafts. Volume 1. Analysis and Discussion. Final Report. (1043 K)
Klote, J. H.

NIST GCR 04-864-1; 35 p. June 2004.

Keywords:

elevators (lifts); fire hazards; smoke; migration; building fires; temperature; smoke flow; doors; windows; smoke transport; people movement; tenability; weather effects; floors; scenarios; visibility; toxic gases; heat exposure

Abstract:

During building fires, smoke often migrates through elevator hoistways to locations remote from the fire. One of the reasons for concern is that a closed elevator door has a leakage area of approximately 0.056 square meters (0.6 square feet). This is a report of a project to study the hazards due to smoke flow through elevator hoistways. Smoke flow and the resulting hazard to life are analyzed for 27 scenarios in 5 buildings ranging from 6 to 58 stories. A fire scenario is the outline of events and conditions that are critical to determining the outcome of alternate situations and designs. In addition to the fire location and heat release rate, the fire scenario includes the status of the doors and other building systems. Other factors addressed are outside temperature, wind, height of elevator hoistway, height of building, leakage paths in the building, leakage of elevator doors, and other shafts. Stairwells are also included. Both sprinklered and non-sprinklered fires are included. Smoke transport throughout the buildings was simulated by a combination of zone fire modeling and network modeling. Options considered for mitigating hazards due to smoke flow through hoistways include (1) the use of enclosed elevator lobbies with automatic closing doors, (2) temporary barriers and (3) judicious positioning of cars within the hoistway. The results of the calculations showed that the use of enclosed elevator lobbies increased the time to reach hazard criteria significantly as compared the results without such lobbies. The use of automatic roll down barriers tended to increase the time to reach hazard criteria to some extent. The use of judicious positioning of elevator cars had no effect on the time to reach hazard criteria.