crowd density considerations - laeog - · pdf filealternatively crowd dynamics can be defined...
TRANSCRIPT
Crowd Density
Considerations
So what does crowd dynamics mean to you?
Crowd - ‘a large number of people gathered
together’ (on line dictionary)
Dynamics – ‘the branch of mechanics that deals
with the motion and equilibrium of systems under
the action of forces’
Is this helping?
Alternatively
Crowd dynamics can be defined as the study of how
and where crowds form and move above the
critical density of more than one person per square
metre. At high density there is the potential for
overcrowding and personal injury. It is therefore
important to understand the dynamics of crowds,
how crowds understand and interpret information
systems, how management systems affect crowd
behaviour. We call this the science of crowd
dynamics.
Prof.Dr. G.K. Still PhD Thesis
So the key elements are
The science of how/where crowds form and move
How/where it reaches critical mass (1 person per
m2)
Safety limits
‒ Design Effects
‒ Queueing
Crowd Density
‒ Crush Potential
Flow Rates
‒ Egress - Normal and Emergency
Prof.Dr. G.K. Still
So why do ‘accidents’ occur?
Lack of understanding of crowd dynamics/behaviour
Lack of attention to crowd densities and movement
Negligence
Complacency
The late Jonathon D Sime, following his review
of a number of crowd ‘disasters’, concluded:
‘Communications systems (Control Centre, CCTV,
and public address) have to be integrated with
safety aspects of:
Architectural Design
Information Technology
Management
Buildings in Use (a thorough understanding of
how to comprehend and use complex settings)’
How can this be applied in practice?
Arrival – the travel arrangements of the spectators
and how these need to be considered
Ingress – upon arrival at the venue/sports ground,
the ingress of spectators must be efficiently
managed
Movement – once inside the sports ground, the
way in which the crowd moves around the ground
can influence the management plan
Exit/Egress – upon termination of the event,
whether planned or unplanned, the movement of
the crowd needs to be managed
Dispersal – post-event travel arrangements and
the movement of the crowd away from the event
must be considered
Assessing crowd related risks:
Ingress
Getting in – queueing, barrier design, information,
management, flow rates, arrival profiles
Circulation
Moving around – queuing, design, information/
signage, management
Egress
Getting out under normal and emergency
arrangements - flow rates, egress times, departure
profiles/[patterns
Emergency egress (during ingress, circulation and
normal egress)
Prof.Dr. G.K. Still
Three primary tools of crowd management
Design
‒ Numbers and capacities of turnstiles/ingress system(s),
constraints, queuing, segregation systems, barriers, locations
for concessions, toilets, seating, rake of stands etc
‒ Normal and emergency conditions
Information
‒ Signage, communication systems, information on tickets, on-
line advice, face to face, lighting
‒ Normal and emergency conditions
Management
‒ Processes, procedures, communication structures
‒ Command/management structures
‒ Stewarding and policing arrangements
‒ Normal and emergency conditions
Prof.Dr. G.K. Still
An approach to planning
NORMAL INGRESS CIRCULATION EGRESS
DESIGN
INFORMATION
MANAGEMENT
EMERGENCY INGRESS CIRCULATION EGRESS
DESIGN
INFORMATION
MANAGEMENT
And finally four S points to consider
Short cuts
The Crowd WILL exploit ALL short cuts
Sightlines
Operational sightlines can be deceptive
Spaces
Not all spaces are used evenly
Speeds
At high density the crowd moves at the pace of the
slowest individuals.
Prof.Dr G.K. Still
Who is responsible for calculating the
capacity for an event?
The objective of the Guide is to provide guidance to ground
management, technical specialists such as architects and
engineers, and representatives of all relevant authorities, in
order to assist them in the assessment of how many
spectators can be safely accommodated within a sports
ground.
Green Guide 1.3
Responsibility for the safety of spectators lies at all times with
the ground safety management. That management will
normally be either the owner or lessee of the ground, who
may not necessarily be the promoter of the event.
Green Guide 1.4
What factors would you consider relevant in determining
an appropriate standing density at an event?
Type of event
Duration of event
Dynamic of crowd (dancing/static etc)
Nature of surface (concrete, mud etc)
Slopes, steps etc
Profile of audience (height, size, families etc)
Lines of sight
Bags, and equipment
Safety management
P & S factors
Barrier plans
Space for movement
Egress and evacuation
This list is not intended to be exhaustive
P & S Factors
‘P’ Factor – an assessment of the physical
condition of viewing accommodation
‘S’ Factor – an assessment of the Safety
Management of that area
Assessment should be given a numerical value
between 0.0 -1.0
‒ e.g. good physical condition or safety
management = 1.0 really poor = 0.0
‒ area with capacity of 5000 where P or S factor
of 0.5 applies will be restricted to 2500.
Progressive Crowd Collapse
Crowd related incidents are often described as
crushes/stampedes
This can imply that the crowd are to blame
whereas causation can probably be attributed to
design/information/management failures
Typically the cause of death is restrictive asphyxia
caused by progressive crowd collapse
These can occur in high density/low stability
crowds
What key guidance may be applicable to
occupant densities?
Event Safety Guide
‒ ‘Generally 0.5m2 of available floor space per person is used for outdoor music events
Guide to Safety at Sports Grounds
‒ For the purpose of calculating the capacity of standing areas at sports ground, the maximum number that can be applied is 47 persons per 10 square metres
‒ In the case of seats, this will be determined by the actual number of seats, less any that cannot be used safely (owing to restricted views or their inadequate condition) and an assessment of the (P) and (S) factors)
‒ …it should be noted that research indicates that spectators can only circulate freely when crowds are no denser than approximately 10-15 persons per 10 square metres
What key guidance may be applicable to
occupant densities?
Fire Safety Risk Assessment (Open Air Events
and Venues)
‒ Standing spectator/audience area or bar – 0.3m2
‒ Assembly area, dance floor or hall – 0.5m2
‒ Dining area, seated bar or restaurant – 1.0m2
‒ Skating rink or sports area – 2.0m2
‒ Display gallery or workshop – 5.0m2
‒ Camping area – 6.0m2
‒ Sales area – 2.0m2
‒ Car park – 2 persons per parking space
So how do you decide?
Appropriate density figures must be agreed on a
risk assessed basis carried out by a competent
person and be bespoke for the event.
This may be based upon a zoned arrangement
(i.e. different from sector to sector)
So how can it go wrong?
Background
8 December 2008 fans are hurt in
‘stampede’ outside Fairfield Halls
Croydon awaiting the arrival of JLS.
The group were appearing in X
Factor at the time.
9 December 2008 JLS apologise and
state they want to play another gig at
the venue for those who missed the
previous appearance.
30 October 2009 severe
overcrowding when JLS attend
Christmas Lights turn on at Trafford
Centre, Manchester.
‒ An estimated 120,000 visitors
attended during the day with
gridlock of road network. Doors
had to be locked with thousands
locked out.
Line up including:
Alexander Burke
Calvin Harris
Girl’s Can’t Catch
JLS
Little Boots
Mini Viva
Natalie Imbrugia
Noisettes
Pixie Lott
Sugababes
Taio Cruz
The Saturdays
Tinchy Stryder
Background
• Event is free and unticketed
• Show commences 2pm on
Saturday 14 November 2009
• Big lights turn on scheduled for
7.30pm
• JLS No 1 in charts
• Accepting we have the benefit
of 20/20 hindsight what would
your assumptions be in terms of
potential numbers attending?
What really happened?
Planning for about 5000 spectators
Estimates suggest about 27,000 turned up
Those who are not admitted are contained behind
drag barriers/heras fencing
Clustering front of stage means space is visible to
rear of arena
Sugababes due on stage
Seeing this some of overspill of spectators start to
climb over barriers. Others put pressure on barriers
which collapse
About 60 injured and real potential for fatalities
Event cancelled
How could ICE/DIM approach have helped?
Key issues
‒ Accuracy of assessment on numbers attending (learning
from Croydon/Trafford Centre
‒ Monitoring of build up – early warning/fill prediction
‒ Counting of admissions
‒ Planning for excess numbers (big screen?)
‒ Appropriateness of barriers, would screening have helped
‒ Poor management/planning?
‒ No plan B
‒ Communication strategy
‒ Free and unticketed, would ticketing have helped?
‒ Inadequate numbers of stewards