Use of EVACNET for Modeling Building Evacuations

Use of EVACNET for Modeling Building Evacuations

Introduction

• Developed by Francis and Kisko, the University of Florida

• EVACNET is a interactive computer program that models building evacuations

• EVACNET takes macroscopic coarse network approach

• EVACNET provides ‘minimum’ amount of evacuation time

Acquire EVACNET4

• EVACNET4 is now FREE.

• One can download from the link: http://www.ise.ufl.edu/kisko/files/evacnet/

Modeling ProceduresDecomposition of the building into network

Supplying data to EVACNET (Nodes and arcs)

Verification of input

Graphical Representation of the network model

Run EVACNET

Analyzing Results

Decomposition: representation as network

1V

2V

3V 5V

4V

6V

Nodes: components of the building

Arcs: viable passageways between the defined nodes

Capacity of node: the upper limit on the number of people that can be contained in the building component

Flow capacity of arc: the upper limit on the number of people that can traverse

Node

Arc

Define nodes

• Let the node represent a single room (or hall, stair, lobby, etc.).

• Combine a set of adjacent rooms into a single node.

• Split up an area, such as a hall, into several nodes.

The number of nodes should not be so many as to make the network model unmanageable.

Node Specifications

• Unique ‘ID’ of a node

• Three parts: node type (two character ), node sequence number, floor number

Example: WP2.3

WP – Node type (Work Place) 2 – Sequence number 0~99 . – Required delimiter 3 – floor number 0~255

WP02.003 is invalid

Suggested Nodes types by EVACNET

  Node Type Node Type Description

  "WP" Work Place

  "HA" Hall

  "SW" Stairwell

  "LA" Landing

  "LO" Lobby

  "ES" Escalator

Special Node Types

• “DS“ : destination nodes. Every EVACNET model must have at least one destination node

• “EL“: elevators/lifts, running on a specified schedule

Arcs

• Viable doorways/passageways between the defined nodes

• Directional: from node1 to node2

• It is allowable to have two arcs connecting two nodes

• No arcs are permitted to leave "DS" (destination) nodes

Arc Specifications

• “from" node specification - the "to" node specification

Example: WP1.3-HA1.3

(Room 301 to third floor hall)

cannot have intervening blanks

Graphical Representation

• An EVACNET network model can and should be drawn graphically

Data required to supply

• node capacity

• node initial contents

• arc flow capacity

• arc transit time

must be represented as integers

Node capacity

• maximum number of people that can be contained in the physical space allocated to the node

• This capacity depends on the usable area associated with the node and the maximum assumed density of people in the node

Example: area=10 m2

max. density=4 persons/ m2 Node capacity=40 (persons)

Node initial contents

• How many/where the people are at the beginning of an evacuation

• Must be less than or equal to node capacity

• Default is zero

Refer to MoE-Table 1

Two attributes of ‘DS’ node

• upper and lower bounds on the number of evacuees allowed to reach the destination

• do not have to be supplied

• The default values are infinity and zero respectively

Arc flow capacity

• Upper bound on the number of people that can traverse an arc per time period

• Determined by the factor limiting the flow from one node to another

• The limiting factor is usually the minimum passageway width, such as a doorway or stairway width, between nodes

• Greater than zero

Arc transit time

• Is the number of time periods it takes to travel from the approximate midpoint of one node to the midpoint of another node

• Not the amount of time it takes to walk through a doorway

• Time period is 5 seconds

• Greater than zero

Adding Data to a Graphic Model

Run EVACNET

ANALYZING RESULTS • SUMMARY OF RESULTS • DESTINATION ALLOCATION• TOTAL ARC MOVEMENT • BOTTLENECKS• FLOOR CLEARING TIME• UNCONGESTED TIMES • NODE CLEARING TIME • BUILDING EVACUATION PROFILE • DESTINATION EVACUATION PROFILE • NODE CONTENTS PROFILE • NODE CONTENTS SNAPSHOT • ARC MOVEMENT PROFILE • BOTTLENECK PROFILE • NON-EVACUEE ALLOCATION

Assumptions of EVACNET

• EVACNET is a linear modeling system. Dynamic arc capacities and arc traversal times do not change over time.

• EVACNET does not model behavioral aspects. The only actions that are modeled are those that lead to achieving the minimum evacuation time.

• EVACNET is based on a global viewpoint; not an individual viewpoint. This means that in achieving the optimal evacuation plan

Components of Total Evacuation Time

Fire Occurs

Time

Time of Fire Detection

Pre-movement time

Flow/Movement Time

Total Evacuation Time