8.1 A barrier must be provided in front of the audience to create a sterile zone between the audience and the stage. Care should be taken when designing this barrier to ensure that it is both an adequate element in itself, properly founded and does not cause injury resulting from excess pressure on individuals against the barrier. Padding is required to prevent this. The barrier should be in the form of an arc or curve with areas for overspill at each end. Barriers should always be placed on level ground. Detailed guidance is given in the publication ”Temporary Demountable Structures: Guidance on Procurement, Design and Use” 1.
8.2 There are clear relationships between stage heights, side stage positions, barrier position, fence heights and pressure relief escape routes. These relationships form a matrix as to how the crowd density and shape develops. Therefore, the layout and arrangement of the front-of-stage barrier cannot be finalised without regard to factors including the stage, position of gates, escape routes, stewarding arrangements, and many other connected factor. 2
8.3 The barrier design is critical to public safety. A front-of-stage barrier not only protects the artists but also serves as a means of relieving crowd pressure and allowing distressed or injured people access to first-aid. The barrier must be designed so that these purposes can be met efficiently. It must be at the right height for the audience and must have a smooth unobstructed raised platform to facilitate crowd supervision by the stewards working behind the barriers. Sight lines, barrier loading, barrier shape and access to first-aid and escape routes are all important. 3
8.4 The front-of-stage barrier (See Fig. A) should be constructed with a solid front, be not less than 1.2m high (over a tread plate) and be designed together with the framing and connections for a pressure of 5kN/m run, applied at a height of 1.2m.
The top of the barrier and the front should be adequately padded and the tread plate in front should be a maximum of 150mm high, a minimum of 1m deep and sloping outwards. The weight of people on this treadplate may be used to counterbalance the horizontal pressure. The barrier shall have a platform behind, 450mm high, for the operation of the stewards between it and the stage and can incorporate struts from the stage to the barrier.
8.5 The barrier should form an integral part of the stage structure. Alternatively an independent demountable/component type barrier which can be shown to have adequate stability and capacity to support a minimum loading of 5 kN/m applied at a height of 1.2m, may be used.
8.6 The barrier should not be less than 4m from the stage at any point and should be in the shape of an arc, the ends of which curve away from the audience, so that any crowd pressure will be sideways towards the ends of the barrier where suitable relief outlets should be provided. At a certain point the 1.2m stage barrier should be raised to at least 2.4m forming a sightline obstruction at the end of the side stages. The location of this feature regulates the width of the audience at the front and should be as wide, as possible, to reduce crowd density, consistent with maintaining a sterile area at both sides of the stage for exits which should be kept clear for use in an emergency.
8.7 The front-of-stage barrier should be designed to withstand a pressure of 5 kN/m at a height of 1.2m. This loading requirement is to prevent structural failure of the barrier and is not necessarily a pressure which can be tolerated by the human body without injury. Experience has shown that women have a lower tolerance to crushing than men and this should be taken into account expected.
8.8 Barrier arrangements should be agreed at the planning meetings and shown on the Site Layout Plan submitted as part of the Statement of Safety Procedures (See Paragraph 5.14). In no circumstances should be these arrangements be changed without the agreement of the Event Safety Officer, in consultation with the Local Authority and Gardaí. The Event Safety Officer should ensure compliance with this requirement.
Multiple Barrier Arrangements
8.9 Crowd density in the front-of-stage area is frequently a cause for major concern. Crowd behaviour, in the form of surging and crowd waves, can also get out of control and pose a serious risk to patrons.
The depth of the zone of maximum crowd pressure, measured from the front-of-stage barrier, can be such as to create severe difficulties for stewarding/first-aid access into the crowd from the front-of-stage sterile zone. These difficulties can be particularly acute where there is a young audience at a high-profile single-artist event. In such circumstances consideration should be given for the use of a multiple-barrier system instead of a single front-of-stage barrier. The use of multiple barrier arrangements may also be warranted at other events where the severe difficulties referred to above are anticipated. As indicated at Paragraph 8.1 barriers should always be placed on level ground, otherwise the pressure indicated at Paragraph 8.7 could be exceeded.
8.10 The overall design and planning for such a system requires a coordinated multi-disciplinary approach in order to achieve an integrated result. Great attention to detail is required for barrier layout, provision of adequate means of escape, barrier design and construction, crowd management and stewarding. Failure to achieve and maintain the requisite standard in any one of these areas may lead to dangerous situations.
8.11 Multiple-barriers should be laid out in a convex curve into the arena like the front-of-stage barrier, with a sterile zone/corridor provided behind each barrier. It may be advantageous to curve the ends of the barriers towards the stage, thus providing greater depth in the centre, and more readily controllable openings at the sides, (Fig. B). The width of the openings should be related to the size of the crowd within the barriers, in order to provide for evacuation from the total area within 3 minutes. It is desirable to have a minimum distance of 15 metres between the last barrier and the mixer tower.
8.12 It is not considered desirable that gates should he provided at the sides, as this could create a dangerous penning situation. By using good sightline management the ingress/egress points will be kept relatively free of patrons and sufficient extra stewards should be provided to control access at these points
8.13 The location of a stage at the goal-mouth end of some sports grounds may not be suitable because of the physical restraints inherent in this location. These factors include the width of the stage, inadequate egress from the pitch at the sides and inadequate space at ends of barriers. If the standards outlined earlier in the Chapter cannot be achieved then the stage should not be erected in this location. In such circumstances it may be necessary to locate the stage along one of the touchline sides, thus allowing more flexibility for access/egress at the edges of the crowd.
8.14 The design of such multiple barriers is likely to be based on a demountable system. Barriers should be capable of resisting a load of 5 kN/m, on both sides of the sterile corridor, and careful consideration must be given to joint details.
While demountable barriers have obvious advantages for flexibility of layout, etc., the Promoter should consider the feasibility of providing permanent anchorage points beneath surface level or the use of augured anchors of adequate strength which could be utilised for occasional barrier installation.
8.15 Both of the barriers which define the sterile corridor should be capable of resisting the design load; it is not acceptable to use a designed barrier on the outer face of the corridor and a light, police-type barrier on the inner face. Alternatively two independent barriers each of adequate stability and a capacity to support a loading of 5 kN/m may be used. It is recommended that the sterile corridor be no narrower than 3m and that both barriers be connected together at ground level, thus increasing the robustness of the barrier system while also providing a low platform from which stewards can operate. See Fig.C.
8.16 Crowd management within a barrier zone requires a high standard of control. Subject to the evacuation requirements in 8.11 above, it may be possible to allow for a higher density within the zone, of up to 0.3m 2 per person; such a higher density may have advantages in preventing crowd waves and surges. When the capacity of the barrier zone has been determined strict precautions must be taken to prevent overcrowding. Colour coded wristlets issued at the entry point on a first-come, first-served basis are recommended as a workable control mechanism, with subsequent strict control on exit/re-entry. Only sufficient wristlets corresponding with the agreed capacity should be issued.
8.17 Multiple-barrier systems require a higher level of stewarding than normally required. In addition to the extra stewards required for the ingress/egress points, the sterile corridor zones must also be stewarded, to the same level as the sterile front-of-stage zone. This stewarding has a three-fold purpose:
(i) to prevent unauthorised entry over the barrier;
(ii) to provide immediate access to deal with problems in the crowd as they arise; and
(iii) to provide for immediate first-aid access; first-aid personnel will also be required in each sterile corridor zone.
Other Barrier Arrangements
8.13 Another type of barrier formation involves a spur type barrier from the centre line of the stage. While this system may prevent lateral movement or swaying in the crowd it could also lead to the creation of pockets where a build-up of crowd pressure could occur on those at the front. This would prevent distressed patrons being rescued over the barrier with no access from behind. This barrier formation is not recommended.
8.19 A spur barrier system projecting from the mixer tower towards the stage area does not have this effect but may prevent lateral movements. Where this system is used, provision must be made for an adequate system of access and egress for distressed patrons, the emergency services and barrier stewards.
8.20 Island-type barrier arrangements have been used elsewhere but exiting arrangements for distressed persons from inside such structures are difficult. Pending further research on this type of barrier their use is not recommended.
8.21 Various other crowd control systems, including the use of a cantilever stage system, are being considered in the United States. Pending experience of these new systems it is not possible to give a recommendation regarding their usage.
1. Shaughnessy, J., Audience and Crowd Control. In: Thompson, G., Focal guide to safety in live performance, Oxford, 1993.
2. Limbe, R., paper presented at Safe-T91, International Conference in Safety and Live Performance, London, 1991.