A Review of Building Evacuation Models - NIST Virtual Library

types of subroutines consist of those which simulate perception and information gathering and
subroutines which simulate information processing and decision-making. An explanation of
each type is provided below:
Subroutines GROUP, OTHERS, AGREE: These subroutines consists of programs that establish
the social environment as the event progresses. GROUP uses the subroutines OTHERS and
AGREE to inform the occupant whether any other occupants occupy the same space as the
current occupant, whether any others in the space have information unknown to the current
occupant, whether others in the space are injured, and whether all occupants can agree on an
effective exit route. Route choice depends upon an occupant’s perception of the situation,
familiarity with the building, lack of information about fire incident, etc.
Subroutine BYSTND: This subroutine will be called if an occupant is occupying a space with an
injured or disabled occupant. BYSTND determines probabilistically if the occupant ignores,
approaches, or stays to assist the disabled occupant.
Subroutine JAMMED: This subroutine enables the occupant to assess the degree of crowding of
the area/location he/she wishes to enter. If the occupant looks ahead to the next space, he/she
counts the number of occupants already there. If this number is larger than the pre-set crowding
tolerance, this route is rejected from the choices of movement.
Subroutine KPOSS: This subroutine allows the occupant to “see” or scan each potential move
and determine if it is physically possible to pass through. This allows the occupant to avoid
paths constrained by walls or other physical barriers.
Subroutine INTRPT: This subroutine probabilistically determines whether an occupant’s
behavior will be interrupted during a time frame, either by remaining in place or backtracking.
Subroutine BACKUP: This allows the occupant to retrace his/her steps back toward the initial
starting position. Once at this point, the occupant resumes the decision-making process.
Subroutines ASSIGN, DOORS1, and DOORS2: This model can assign a bias to the occupant’s
decision-making behavior. This is meant to assign probabilities to decisions made throughout
the simulation, which may be more likely than others. DOORS1 controls the probability of the
occupant opening a closed door during the evacuation. DOORS2 controls the behavior of
whether or not the occupant will close the door behind him/her once passing through.
Subroutine EQUALZ: This is used to satisfy the condition of “no bias” or equalizing the
probability values of available alternative moves.
Subroutine TBIAS: This routine establishes probabilities for moves which favor maximizing an
occupant’s distance from threat, such as fire or smoke.
Subroutine EBIAS: This subroutine uses probabilities that favor moves that minimize an
occupant’s distance from an exit.
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