A Review of Building Evacuation Models - NIST Virtual Library

• 50 % of normal speed if the occupant assists another, and 30 % faster than this adjusted value
if the occupant considers the situation to be serious.
• 60 % of normal speed of the smoke is bad (S>0.4) and the (H-D) (depth of lower layer) is
less than 1.5 m
Output: The output includes the number of occupants out of the building, those trapped, and the
total evacuation time. The actions of individual occupants at all time periods throughout the
simulation are also included in the output.
Use of fire data: EXITT is designed to import output from FAST to simulate smoke throughout
the building. This assumes a 2-layer smoke distribution. EXITT also accepts input of smoke
density in the upper layer and the height of the two layers in each room at each time period.
Import CAD drawings: No, CAD drawings of the building cannot be imported into EXITT.
The building is described by providing the number of rooms, nodes, and exits, the height of each
room, the room location of each node, whether the exit was a door, window, etc., and the
distances between the nodes. If a window cannot be used for evacuation, it is not included into
the model.
Visualization capabilities: The movement of the occupants can be displayed graphically on the
computer screen.
Validation studies: None noted.
Special features:
Manual exit block/obstacles – Yes, if smoke is very heavy (which can be input by the user)
Fire conditions affect behavior Yes, these can be imported from FAST or user-defined (OD
and smoke layer heights) per time period.
Defining groups – Yes, capable and needs assistance.
Disabilities/slow occupant groups – Yes.
Delays/pre-movement time – Delays are associated with the activities during a preparation and
response time.
Route choice of the occupants/occupant distribution – Route choice is dependent on a list of
information, many of it conditional to the environment, during the evacuation as well as the
familiarity with the building.
Limitations: This model is used only for residential buildings. Occupants respond to smoke
conditions only, not toxicity or heat. Also, many of decision rules are based on author judgment.
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