It is a requirement of the Work at Height Regulations 2005 that unless a scaffold is assembled to a generally recognised standard configuration then the scaffold should be designed by bespoke calculation, by a competent person, to ensure it will have adequate strength, rigidity and stability while it is erected, used and dismantled.
At the start of the planning process, the client should supply all of the relevant information to the scaffold contractor to ensure that an accurate and proper design process is followed. Typically this information should include:
- the site location
- the period of time the scaffold is required to be in place
- the intended use of the scaffold
- the height and length and any critical dimensions which may affect the scaffold
- the number of boarded lifts
- the maximum working loads to be imposed and the maximum number of people using the scaffold at any one time
- the type of access onto the scaffold i.e ladder bay
- whether there is a requirement for sheeting, netting or brickguards
- any specific requirements or provisions i.e pedestrian walkway
- the nature of the ground conditions or supporting structure
- information on the structure or building the scaffold will be erected against together with any relevant dimensions and drawings
- any restrictions that may affect the erection, alteration or dismantling process
Prior to installation, the scaffold contractor or scaffold designer can then provide relevant information about the scaffold. This may be a stand alone document or may included in the drawing, and should include:
- the type of scaffold required i.e tube and fitting
- the maximum bay lengths
- the maximum lift heights
- the platform boarding arrangement and the number of boarded lifts that can be used at any one time
- the safe working load and load class
- the maximum leg loads
- the maximum tie spacing both horizontal and vertical and tie duty
- details of additional elements which may be a standard configuration or may be specifically designed
- any other information relevant to the design, installation or use of the scaffold
- reference number and date to enable recording, referencing and checking
For scaffolds that fall outside the scope of a generally recognised standard configuration the design must ensure that safe erection and dismantling techniques can be used throughout the duration of the works. To ensure stability for more complex scaffolds, drawings should be produced and, where necessary be supplemented with specific instructions. Scaffold structures that normally require bespoke design include, but are not limited to:
- all shoring scaffolds (dead, raking, flying)
- cantilevered scaffolds
- truss-out Scaffolds
- façade retention
- access scaffolds with more than the 2 working lifts
- buttressed free-standing scaffolds
- temporary roofs and temporary buildings
- support scaffolds
- complex loading bays
- mobile and static towers
- free standing scaffolds
- temporary ramps and elevated roadways
- staircases and fire escapes (unless covered by manufacturers instructions)
- spectator terraces and seating stands
- bridge scaffolds
- towers requiring guys or ground anchors
- offshore scaffolds
- pedestrian footbridges or walkways
- slung and suspended scaffolds
- protection fans
- pavement gantries
- marine scaffolds
- boiler scaffolds
- power line crossings
- lifting gantries and towers
- steeple scaffolds
- radial or splayed scaffolds on contoured facades
- system scaffolds outside manufacturers guidance
- sign board supports
- sealing end structures
- temporary storage on site
- masts, lighting towers and transmission towers
- advertising hoardings or banners
- rubbish chutes
- any scaffold structure not mentioned above that falls outside the ‘compliant scaffold’ criteria in existing industry guidance from system manufacturers or otherwise