Stage barriers have a variety of uses and are now an important piece of equipment for event organisers. Although known as 'stage' barriers, they can be used wherever crowd density is anticipated, eg licensed bars at outdoor events.
The stage barrier is designed around a basic 'A' frame to be load-bearing, and is therefore normally used where there is a risk of crowd pressure.
Most stage barriers:
- are constructed of steel or aluminium, ideally fully welded. They should not be riveted in parts, nor should soft materials such as wood be used
- have individual sections of around 1200mm high and 1m wide
- have a footplate that the audience stands on to stabilise the system
- have a top, horizontal, rail that should be smooth, rounded and fall flush on the front vertical fascia (audience side)
- should have a step on the rear (stage side) that working personnel can use, eg to offer water to the audience or extract people over the barrier
To be fully effective, a stage barrier has to be built following the correct procedure. It will only be as strong as its weakest link, so once a system has been built, the joining method should be in place, ie location, pins, bolts etc.
The barrier should:
- have smooth lines
- have no rust or disfigurement
- have all rivets in place and not rotating
- have smooth welds, with no fractures
- be stable, with all bolts or fixings correctly installed to prevent movement and possible finger / toe entrapment
- have no access gates on pressured sections
Along with the overall strength and stability of the barrier, the organiser needs to consider its shape. The barriers are designed to retain and resist audience pressure, so it is critical to make sure that barrier location and shape do not lead to the creation of 'pockets' in which people can become trapped, or from which the pressure created by the movement of a crowd cannot be safely dissipated.
You should erect barriers with escapes to the right and left of the stage, so that people can move away to safety. If a venue has restricted space, a straight barrier is suitable.
However, for large venues, particularly those outdoors, a convex barrier extending into the audience may be preferable. In such circumstances, the barrier should consist of short, straight sections installed at angles to each other to form a curve across the main performance area, extending to the ends of the side stages.
A curved barrier can provide other benefits:
- dissipating audience surges away from the centre of the stage
- assisting means of escape
- providing a wider front row sightline
- improving performer safety by placing a greater distance between the stage and the front-of-stage barrier, therefore making it difficult for members of the audience to reach the stage
- providing a wider 'pit 'area in which stewards and first-aiders can operate – this area should be designed to assist the work of stewards, first-aiders and paramedics
Barriers around thrusts
A thrust is a section of the stage that projects from the main body of the stage towards the audience. Where thrusts extend into the audience, provide a barrier that complies with the design criteria and loading factors for front-of-stage.
It is advisable to construct a thrust in such a way that it does not create poor sightlines. Make sure that such stage designs do not result in concave trapping points, from which audience members cannot escape.
With less conventional venue layouts that have in-the-round stages, B stages and other satellite performance spaces, it is important to design the barrier systems to avoid penning people in and creating trapping points.
Side-stage barriers or fences
The construction of a high side-stage fence to form a sightline obstruction will make sure that important exits to the right and left of the stage are kept clear and are available for use in an emergency. Always provide this sort of fence for standing audiences.
Additional barrier arrangements
At large, outdoor events it may be possible to have an additional barrier arrangement to reduce the likelihood of crowd collapse. This could take the form of a finger barrier, extending into the audience, or a multiple-barrier arrangement.
If a finger barrier is used, careful design is needed to avoid creating trapping points. The barrier should be able to withstand the same crowd loading as the front-of-stage barrier and enable stewards and first-aiders to have access to the audience along its length.
For large events, it may be possible to use a multiple-barrier system (ie double or triple barriers in front of the stage). If such a system is proposed, you should agree escape arrangements with the local authority and fire authority.
Multiple-barrier systems are not suitable for all venues; for instance controlled side escapes may be difficult to incorporate in some venues. It is unsafe to pen an audience in flat, open areas by means other than the arrangements described in the following paragraphs and could create difficulties with evacuation.
Where double- or triple-barrier arrangements are used, the barriers should form a convex curve into the audience with escapes from both ends. Providing a corridor or area behind each curved barrier will give stewards and first-aiders adequate access to the audience along the length of the barriers. The barriers used to achieve this should meet the required minimum loading.
With a very enthusiastic audience, it is likely that many of the problems normally encountered at the front-of-stage barrier will also be experienced at the barrier furthest from the stage. It is therefore essential that you provide adequate numbers of first-aiders and stewards. However, because of the wider sightline potential (75% in some cases), and the increased distances from the stage, the incidence of audience surge and crushing may be reduced.
Where front-of-stage barriers end, they will normally join to another type of fence or barrier, continuing the secure area backstage. Such junctions need to be properly secured and be free of sharp or projecting edges. Consider blanked-out or solid fence sections where sightlines to the stage are still good – this helps prevent a build-up of audience members where the pressure barrier ends and the less robust fencing type begins.
It is worth bearing in mind that this type of barrier is difficult to reposition quickly once it is in place.
For technical requirements on the design, loading, testing and installation of barriers – Temporary demountable structures. Guidance on design, procurement and use (3rd edition) Institution of Structural Engineers.