With a continued push by the major football codes to expand their games into regional and country areas (particularly through pre-season trial games and tournaments), local Government owners of regional stadiums and venues are, not surprisingly, keen to attract these events to their venues. As a result, a growing number of venues are seeking to develop their crowd capacities to meet the respective leagues' minimum requirements for top class sporting events. While these leagues demands may serve as the motivation for establishing maximum crowd numbers, the OH&S and common law duties of care also require venue managers and operators to understand what constitutes safe crowd numbers in order to manage them effectively.
Many venues in regional areas are characterised by small areas of ticketed seating and large open areas for multi-purpose general admission. These can be used for standing room, or as temporary corporate facilities. But when big games and large crowds come to town, how do managers know what is a safe capacity for their venue?
There are several models available to assist venue managers and event organisers to establish their venue's crowd capacity. Most commonly, the 'Guide to Safety at Sports Grounds, (the 'Green Guide'), is recognised as an industry standard for such an exercise. Within the Green Guide, four factors are important: the physical layout of the venue (P-Factor); the effectiveness of safety, emergency and crowd management systems in place (S-Factor); the normal egress time taken to empty a viewing area within the venue after an event, and the egress time taken to empty the viewing areas in an emergency, based upon the obvious risks within the venue (particularly fire hazards).
Venue layout and safety systems
To establish the P-Factor and S-Factor, managers need to consider a range of variables that help quantify risk control effectiveness, reflected in a score of between 0-100. A high score shows effective controls and low residual risk, and a low score suggests the opposite. The scores are put into a formula that discounts the available viewing areas (based upon the level of residual risk) and gives a maximum safe number of people per viewing area based upon either the P-Factor or S-Factor score, whichever is the lower.
Normal egress The analysis then considers the total linear meterage of all exits from each viewing area. This calculation applies an assumption called the 'eight minute rule'. That is, in theory it should take no longer than eight minutes under normal operating conditions for a person to leave the viewing area and move into a free flowing exit system. This figure is based upon research into egressing crowds that suggests that beyond eight minutes people become agitated, which then leads to crowd safety problems.
The calculations apply a maximum crowd flow rate based upon whether the crowd is either standing or sitting in the viewing area, and range between 109 spectators a metre per minute to 73 spectators per metre per minute respectively. These thresholds can be reduced even further where the event risk assessment and expected crowd profile suggests the crowd attending may include people with mobility impairment, families with children, or people carrying additional items such as deck chairs. Consideration should also be given if there are concessionaires along the egress route, and where the location of venue exits may be physically or visibly obstructed.
Under emergency conditions the maximum flow rates use the same safe rates as for normal egress conditions, however the maximum exit time from the viewing accommodation to a place of safety is discounted based upon the level of safety risk. These times range from between two and a half minutes for high-risk environments (for example, being in close proximity to hazardous materials or dangerous goods), to eight minutes for areas with no apparent evidence of significant safety risk.
Deriving safe crowd capacity
With the calculation of these four values, the appropriate safe capacity is the one that results in the lowest safe crowd number.
Improving safe capacities There are a range of things a venue can do to increase crowd capacity, based upon these calculations. For example, where P-Factors are the key limiting factor for crowd flow, improvements in physical conditions of the viewing areas such as the number and location of temporary overlay or the ground surface quality and gradient can help. Where S-Factors are the problem, selling only low strength alcohol, increasing crowd safety staffing levels, improving the effectiveness of safety and emergency planning, or increasing the level of signage may also go some way to improving the capacity calculation.
Where egress duration is a defining factor, limitations on restricted items, improvements in the effectiveness of safety risk controls, increases in the number, location and accessibility and, most importantly, the linear width of emergency exits may also improve the venue's crowd capacity potential. Crowd management models
Another useful resource in helping to improve crowd capacity and crowd management was developed by American crowd flow expert, Dr John Fruin. Through research he identified four variables that have influenced major crowd disasters, developed what he termed the 'FIST' (force, information, space and time) model.
The forces on a crowd increase with the movement of people during ingress, migration within the venue between viewing areas and amenities and, most commonly, during egress. During these times, 'bottlenecks' or multi-directional crossovers that obstruct crowd flow are areas where crowd density increases. Under mild densities (that is, one to two people per square metre), individuals within the crowd experience limited movement but should not be uncomfortable. Beyond two people per square metre, involuntary contact may occur and is typically avoided by people in crowds unless it is at a deliberate high crowd density event, such as a music festival. As density conditions increase beyond four people per square metre, crowd safety breaks down. The Green Guide uses a maximum crowd density threshold of 47 people per ten metres2, however this number is discounted based upon the presence and effectiveness of risk controls. Beyond this limit, compression asphyxiation may occur.
The appropriate safe crowd density for any venue varies depending upon the expected crowd's profile, physical factors of the venue and overlay, as well as safety and emergency management factors. It should be noted that it would be extremely difficult for any venue or event to argue that their physical layout and safety management systems were so good that it should allow them to safely meet this threshold. This would allow no room for error and assumes that absolutely nothing will go wrong. This is a dangerous assumption to make. Information
Audible and visual information available to the crowd is a vital tool in influencing patron anxiety arising out of being in a crowd. Providing clear, legible and appropriate information will help improve people's comfort levels and reduce the risk of panic and crowd surge. Useful strategies include provision of directional signage with appropriate language and pictograms, use of video scoreboards, variable messaging signage (VMS), audible public address announcements, competent crowd ushers and more.
Space design includes the configuration of temporary structures and consideration of their impact upon crowd thoroughfares and movement. Different spaces are affected by different crowd types and the anticipated activities while at the venue. Other factors to consider include designing easily accessible exits to provide a choice of unimpeded and well signposted routes, maintaining dedicated egress routes in general admission standing areas as well as ensuring ramps, stairs and escalators are visible and clear of obstacles.
While the Green Guide considers a maximum theoretical time for emptying viewing areas within the venue, the FIST model notes that as timeframes for crowd movements are compressed, so too is the risk increased from crowd force and crush related problems. The obvious strategies here include staggering arrivals and departures through co-ordination with public transport, the use of post-match entertainment, or selling food, beverages or merchandise. However, careful consideration should always be given to emergency response and evacuation procedures at all phases when the venue is occupied, including during staggered crowd egress and outside event of times.
Managing event-related risk
The ultimate message in this article is there are many factors that affect event-related risk, and all should be considered. Whilst some have been addressed here, the setting of crowd capacities is a core feature for managing crowd safety. The appropriate capacity for each event may vary depending upon the type of event, the people attending, the level of competence of the event organiser, the certainty and control of crowd numbers and the specific risk profile of each event.
Establishing a safe crowd capacity may be important for understanding the event's commercial viability and minimising any liability, but it is absolutely critical for the reputation of all parties responsible for making the event a success.
Note: This article serves as a guide only and is not intended to serve as a substitute for conducting a formal risk assessment of crowd capacity at sports grounds or any other venues. Venue owners and event organisers are advised to do their own diligence regarding safe crowd capacities and to use only competent and qualified persons to establish these numbers.
[This article has been published in Australian Leisure Management magazine September/October 2008 edition].