Scientists launch world's most advanced crowd simulation and evacuation software

Citation

(2001), "Scientists launch world's most advanced crowd simulation and evacuation software", Disaster Prevention and Management, Vol. 10 No. 2. https://doi.org/10.1108/dpm.2001.07310bad.001

Scientists launch world's most advanced crowd simulation and evacuation software

Scientists launch world's most advanced crowd simulation and evacuation software

Scientist at the Univserity of Greenwich have released the new generation of the evacuation and crowd simulation software, building EXODUS. Version 3.0 incorporates new capabilities that enable building engineers to perform realistic desk top simulations of people in both normal and emergency conditions. The software simulates not only how individual people interact with each other and the built environment, but also how they are debilitated by hazards such as heat, smoke and toxic gases. To simulate these complex relationships, the software uses sophisticated rule based systems to control the interaction of five advanced sub models. The software draws extensively on data and experience captured from experiments and real life incidents. For example, the human behaviour sub model includes rules governing the behaviour of people interacting with smoke in fire situations. The arrival of this level of sophistication on the desk top means that the building engineer can test more designs in less time to reach the optimal solution, free from costly and unrealistic assumptions.

The new release, Version 3.0, incorporates four key advances:

1. 1.

   Advanced virtual reality visualisation. The introduction of a virtual reality post-processor interface enables simulations to be played as advanced 3D movies displaying people as actual figures moving and interacting.

2. 2.

   Enhanced realism. A number of new features increase the realism of human behaviour in the model. For example, an "itinerary list" function allows groups or individuals to perform simple tasks prior to exiting. For example, in an evacuation, it is now possible for occupants to collect a jacket or handbag prior to exiting.

3. 3.

   People circulation in non-emergency conditions. Through the introduction of the "itinerary list" function, Version 3.0 extends the range of the software beyond emergency scenarios to normal circulation patterns in buildings. This will help to predict how a building and users will interact in normal usage such as peak congestion periods in transport terminals, shopping malls and sports, conference and exhibition venues.

4. 4.

   Cfast interface. In previous versions of building EXODUS, the specification of fire hazards has been a complex task. Version 3.0 addresses this issue by incorporating an interface with the popular fire zone model, CFAST V4.01. By allowing users to read CFAST history files into building EXODUS, the facility simplifies the process of specifying fire scenarios.

The sophistication of building EXODUS has made it one of the world's leading design tools for simulating evacuation from buildings. Since its launch in October 1996, the package has been used by engineering consultancies, architects, research laboratories, regulatory authorities, police forces, fire brigades and universities in 17 countries: Australia, Belgium, Denmark, Finland, Germany, Hong Kong, Indonesia, Ireland, Korea, Italy, Luxembourg, The Netherlands, Portugal, Sweden, Taiwan, the UK and the USA. The package has been used to model the evacuation capabilities of a wide range of proposed or existing buildings, ranging from hospitals and shopping complexes to the Olympic Stadium in Sydney and the Millennium Dome in Greenwich.

"… building EXODUS Version 3.0 gives building engineers powerful new options for simulating crowd movement and evacuation on their desk tops," says Professor Ed Galea, Director of the University's Fire Safety Engineering Group and developer of building EXODUS. "The new capabilities – a direct response to needs identified by our clients – represent a quantum leap in the sophistication offered by building EXODUS, and will help to maintain the software as one of the most advanced crowd simulation packages in the world."

Why engineers need to simulate people movement in buildings building EXODUS is believed to be the first evacuation model to incorporate the four key areas – configurational (structural), environmental, behavioural and procedural – which govern evacuation.

The model uses a series of five sophisticated sub models to simulate, not only how people interact with each other and the built environment, but also how they are debilitated by hazards such as heat, smoke and toxic gases (see technical information fact sheet). The sub models interact to reveal how a defined group of people attempt to navigate a space or escape from it – from the routes they use and the times they take, to the moment that individuals are asphyxiated. The model even caters for the representation of people with movement disabilities.

It is not possible to consider these factors using traditional methods, which rely on a set of rigid rules, such as the number of exits required for a given floor space. At best, these traditional methods only reveal whether a design crosses the threshold of acceptability; not which of a range of acceptable designs is best. Building EXODUS indicates relative performance and allows engineers to test more layouts to arrive at the optimal solution. The computer package can also help to demonstrate that a building complies with performance-based building standards.

The arrival of this level of sophistication on the desk top means that the safety engineer can test more designs in less time to reach the optimal solution, free from costly and unrealistic assumptions.

"The advent of novel building designs such as the Millennium Dome in London has heralded a new era in building standards," says Professor Ed Galea. "It is the era of objective 'performance-based' standards, which do not prescribe how to make a building safe; simply how safe a building must be. And it is the era of the computer simulations which can be used to demonstrate that level of safety."

The EXODUS software simulates people-people, people-fire and people-structure interactions. The model tracks the trajectory of each individual as they make their way out of the enclosure, or are overcome by fire hazards such as heat, smoke and toxic gases. The software has been written in C++ using object orientated techniques and utilises rule-based software technology to control the simulation. For additional flexibility these rules have been categorised into five interacting sub models (see below) which operate on a region of space defined by the geometry of the enclosure. This can be: read from a geometry library; constructed interactively using the tools provided; or read from a computer-aided design drawing using the DXF format. Internally the entire space of the geometry is covered in a mesh of nodes. The nodes are then linked by a system of arcs. Each node represents a region of space typically occupied by a single occupant.

Sub models

MovementControls the physical movement of individual occupants from their current position to the most suitable neighbouring location, or supervises the waiting period if one does not exist. The movement may involve such behaviour as overtaking, side stepping, or other evasive actions.

Behaviour

Determines an individual's response to the current prevailing situation on the basis of his or her personal attributes. The sub model passes this decision on to the movement sub model. The behaviour sub model functions on two levels, global and local. The local behaviour determines an individual's response to his or her focal situation, while the global behaviour represents the overall strategy employed by the individual. This may include such behaviour as, exit via the nearest serviceable exit or most familiar exit.

Occupant

Describes an individual as a collection of defining attributes and variables such as name, gender, age, maximum running speed, maximum walking speed, response time, agility, etc. Some of the attributes are fixed throughout the simulation while others are dynamic, changing as a result of inputs from the other sub models. Hazard controls the atmospheric and physical environment. It distributes pre-determined fire hazards such as heat, smoke and toxic products throughout the atmosphere and controls the opening and closing of exits.

Toxicity

Determines the effects on an individual exposed to toxic products distributed by the hazard sub model. These effects are communicated to the behaviour sub model which, in turn, feeds through to the movement of the individual.

For further details contact Professor Ed Galea, Fire Safety Engineering Group, University of Greenwich, 30 Park Row, Greenwich SE10 9LS, UK. Tel: +44 (0)20 8331 8730; Fax: +44 (0)20 8331 8925; E-mail: e.r.galea@greenwich.ac.uk www: http://fseg.gre.ac.uk