Model Name: ASERI
Version: ASERI 3.0
Classification: Evacuation Model
Very Short Description: Individual-based modeling
of egress movement in complex
geometries, including behavioral response to smoke
and
fire spread
Modeler(s), Organization(s): Dr.
Volker Schneider, I.S.T. Integrierte Sicherheits-
Technik GmbH, Frankfurt / M., Germany
User’s Guide:
ASERI – Users’ Guide (hardcopy and
complete online
documentation – available in German and
English)
Technical References:
ASERI – Technical Reference (hardcopy and
complete
online documentation – available in German
and English)
Validation References:
T. Paulsen, H. Soma, V. Schneider, J. Wiklund,
G. Løvås:
Evaluation of Simulation Models of Evacuation
from
Complex Spaces (ESECX), SINTEF Report STF75
A95020, Trondheim, Juni 1995
V. Schneider, R. Könnecke:
Simulation der
Personenevakuierung unter Berücksichtigung
individueller
Einflußfaktoren und der Ausbreitung von
Rauch, vfdb-
Zeitschrift 3 (1996) 98
H. Weckman et al.: Evacuation of a Theatre : Exercise
vs
Calculation, Fire and Materials 23 (1999) 357-361
Availability:
I.S.T. Integrierte Sicherheits-Technik GmbH, Feuerbachstr.
19, 60325 Frankfurt / M., Germany, Phone (069)
72 11 68,
Fax (069) 72 11 94, Email IST-HSK@t-online.de
Price:
24.350,- DM (not including VAT, including hotline
service
and training)
Necessary Hardware: Pentium III,
Windows 98 / 2000 / NT
Computer Language: C++
Size: Approximately 10MB of disk space, at least
64MB of
RAM required, disk space for data output depending
on
scenario (typically several hundred MB)
Contact Information: I.S.T. Integrierte Sicherheits-Technik
GmbH, Feuerbachstr.
19, 60325 Frankfurt / M., Germany, Phone (069)
72 11 68,
Fax (069) 72 11 94, Email IST-HSK@t-online.de
Detailed Description:
Basic concept
Each occupant is treated as an individual
person, moving inside the building or any other
geometrical scenario that may be amenable to egress
movement (e.g. mass transport
vehicles). The individual egress movement is governed
by certain behavioural aspects
that are triggered by external stimuli and limitations
due to the movement of other
occupants. Individual decisions and corresponding
behaviour may contribute to a delay in
starting the evacuation or interrupts, especially
in the initial phase of the evacuation
process. Furthermore, the choice of the egress
path is strongly influenced by individual
aspects like knowledge of the building layout
or smoke tolerance. Basic features of
behavioural response can be modelled in a statistical
way.
The probabilistic method allows
for a more profound evaluation of the evacuation
process by performing Monte-Carlo simulations.
A number of replicate runs with
identical input data are performed and statistically
analysed, yielding not only mean
values of egress times but also standard deviations
and confidence limits. Furthermore,
visualisation of the movement of the evacuees
and corresponding dynamic graphical
information (including the generation of AVI video
sequences) on the population and
crowd density in sensitive areas contributes to
better understanding of the mechanisms
individuals interact with each other and with
the physical environment, including fire
spread and smoke movement.
Building Layout
In ASERI, the geometrical scenario
(building) is defined in a hierarchical way. A
building is composed by a number of levels or
stories, connected by stairways or ramps.
Each level is subdivided into a number of rooms
and corridors. Rooms, corridors, stairs
and safe areas are the basic geometrical units.
These units are defined by the respective
ground-plan (generally represented by a polygon)
and by size and position of doors and
passages. Inside the units obstacles can be defined
with arbitrary size and position. Safe
areas - the possible destinations of the occupants
- usually are regions outside the
building associated with exits, but can also be
located inside, thus representing regions
that (temporarily) give shelter. The number of
levels, units, passages and obstacles is only
limited by available computer memory. It is therefore
possible to model very large and
geometrically complex buildings.
Smoke spread and dispersion of combustion
products
Time-dependent temperatures and
concentrations of smoke, carbon monoxide, carbon
dioxide, oxygen and hydrogen cyanide can be related
to each unit. Smoke concentration
is expressed in terms of visibility.
Individual space requirement
Body size is represented by shoulder
and chest width, according to the well-known
concept of body ellipse. Furthermore, a minimum
inter-person distance and the
maintenance of a boundary layer clearance from
walls and stationary obstacles is
considered. Shoulder and chest width can be assigned
individually, either by explicit
input or by specifying of a distribution function
appropriate for the respective population.
By introducing effective size parameters, this
concept allows for the definition of persons
with increased space requirement, including persons
with limited mobility, occupants
with luggage or adults accompanied by smaller
children.
Individual movement
The occupants’ movement is
defined by the individual walking speed and the
orientation
of the corresponding velocity vector. The orientation
is derived from the person's local
position and the respective individual goal (e.g.
nearest exit or prescribed exit).
Furthermore, obstacles and the presence of other
occupants influence the movement.
Route choice is influenced by external impact
and the behaviour of the other evacuees. It
is thus possible for an individual to alter the
original egress route choice in order to avoid
smoke or congestion caused by unbalanced exit
use.
Time is advanced by discrete time
steps of 0.5 seconds. For this short interval
of time, the
corresponding trajectory of a moving person can
be represented by a straight line. The
movement algorithm of ASERI ensures that no conflict
with walls, obstacles or the
movement of other occupants occurs.
Impact from fire hazards
The incapacitating effects of exposure
to asphyxiates and heat are calculated using the
effective fractional dose model of Purser. Based
on the movement of the evacuees and
the individual dose, exposure is calculated with
respect to CO, HCN, CO2 and O2
depletion. Synergetic effects, specially hyperventilation
caused by the presence of CO2,
are considered in Purser’s model. In addition,
critical concentration thresholds of toxic
fire effluents and oxygen are included in ASERI.
Thermal stress caused by radiated or
convected heat can also be expressed in terms
of an effective dose, considering that short
exposure to a high temperature is more incapacitating
than a longer exposure to a lower
temperature.
The obscuring effects of smoke are
described by assigning a time-dependent visibility
to
each geometrical unit. Beside the toxic effects
of smoke components, the slowing down
of walking speed due to reduced visibility and
certain aspects of behavioural response to
smoke are considered in ASERI.
