Introduction
- This guidance provides a brief overview of the topic and will also direct people to where further detailed information and advice can be sought
- Temporary demountable structures include marquees, grandstands, stages, and related structures that are used at a wide range of public and private events
- These types of structures are usually designed to be easily and quickly erected and dismantled and are capable of adaptation to different situations. This often means that, from a structural engineering perspective, they are relatively lightweight, made from slender components and need to be designed, erected, and inspected by competent persons before they are used
Responsibility for safety
The primary responsibility for safety in the erection, use and dismantling of a temporary structure lies with the client. The client is the person making decisions on what they need and how much they want to spend on their event. This is known as being the ‘Duty Holder’. It is imperative that the client fully understands their role, which in turn can help them correctly procure a suitable structure for their event.
To cover their legal responsibilities, clients need to ensure they have undertaken several distinct steps. These steps can be summarised as follows:
- Appointing a competent Principal Designer and Principal Contractor. If the client does not do this in writing, the client retains the duties of those roles
- Allocating sufficient time and resources to allow the project to be carried out safely
- Preparing and distributing relevant information to other duty holders
- Making sure that the Principal Designer and Principal Contractor carry out their duties
- Providing welfare facilities on their site
Procurement
Procuring the correct structure is the first and most important step in ensuring a structure can be built and used safely for its intended purpose. If an inappropriate structure is procured it is likely to cause safety and financial issues throughout the process. For this reason, it is imperative that time and effort is allocated by the client to the procurement process for all structures that are required for their event, no matter how large or small.
Clients should take the following steps:
- Obtain written evidence that competent persons are employed to design, erect, inspect and dismantle the structure
- Confirm the expected nature and character of spectator activity at the event
- Provide the Designer with a written technical specification of requirements (such requirements may be specific to the country in which the work is being undertaken)
- Make suitable arrangements for managing the project safely
- Obtain approvals from the relevant enforcing authority in good time
- Make sure that an event management plan is available, which includes a plan for dealing with adverse weather conditions — particularly strong winds, heavy rain and lightning
Use of Structures
It is important to remember that a demountable structure is unlikely to be able to withstand the same amount of wind, rain, or snow as a permanent building such as a house or office block.
The supplier of the structure should state what these design limits are and how they may affect the stability and safety of the structure. There is a big difference between a structure that has been designed to withstand 18m/s wind speed, and one that is designed for 25m/s. This apparently small change could mean the difference to an event going ahead or being cancelled for safety reasons during a storm.
For the structure to be used safely during its time on site, it is essential that the client writes plans that show what happens to the site if the design limits of the structures are exceeded. These written plans must be thorough and realistic to ensure the safety of all persons who may be visiting or using the structures in any capacity.
Where can I get help?
The Institution of Structural Engineers, supported by the Health and Safety Executive, has published guidance on Temporary demountable structures. The fourth edition contains essential information on the procurement, design, erection and use of temporary demountable structures, including grandstands, stages, fabric structures, hospitality units, and fencing and barriers. Towers and masts that support media facilities are also included.
Detailed recommendations are given for grandstands, stages, and special structures. There is a section on fabric structures and further advice on ancillary and special structures to support lighting equipment, video screens, loudspeakers, and the like.
The Guide is based on practices in the UK and Europe, but the principles described are appropriate for application elsewhere. It is written for clients, event organisers and venue owners, designers, regulatory and local authorities, as well as contractors and suppliers of demountable structures.
The SGSA Guide to Safety at Sports Grounds also contains a full chapter on advice for the use of demountable stands and a very useful checklist to show whether all design, installation and operational management have been considered.
Advisory Group on Temporary Structures (AGOTS)