The next step

The HSE’s microsite on scaffold design

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Employee fell eight metres when scaffold collapsed

The accident

On 2 September 2016 scaffolding was being erected at a four-storey property in Glasgow to allow access for roof repairs. The scaffold was almost complete, but as an employee was fitting toe boards to a cantilever section, it partially collapsed, causing him to fall eight metres to the ground below. He suffered severe injuries.

Path of destruction

An investigation by the HSE found that the company had begun on the right track. It had carried out a risk assessment and method statement for the work which, at the planning stages, was for the construction of an eight-metre-high scaffold tower. However, things started to unravel when it emerged that the tower had not been erected in quite the right place. Rather than disassemble and reassemble it, a decision was made to add a cantilever section. This meant that the scaffold base stayed where it was and a new section was added to the side. No formal design process was undertaken for the cantilever section even though the new addition would create quite a complex structure.

Worse still, as the alterations began it became apparent that there was no equipment on site to tie it to the building. Now stuck on a path of improvisation the team decided to support the cantilever section by splicing it to the frame of the scaffold tower. However, the guesswork failed and the top section of the tower was unable to support the weight of the cantilever causing the structure to collapse. In court JR Scaffold Services Ltd pleaded guilty to breaching s.2(1)Health and Safety at Work etc. Act 1974 and was fined £5,000.

Tip. Whenever practical difficulties arise on site, it’s always best to go back to the drawing board. Recheck whether the alternative options you’re considering are appropriate given the background assumptions, preparations, equipment, environment and experience of the team.

Scaffolding requirements

Scaffolding projects must comply with the Work at Height Regulations 2005 (WAHR) which require those designing scaffolding to carry out strength and stability calculations, unless the access equipment can be assembled “in conformity with a generally recognised standard configuration” . This appears to be where the scaffold contractor went wrong in this case, because the structure moved from one which had a standard configuration to one which should have had detailed design calculations.

Note. The standard configurations are found either in the manufacturer’s instruction booklet if it’s a system scaffold tower, or otherwise in a document referred to as TG20 , which should be available to all scaffold contractors.

Tip. If you’re appointing scaffolding contractors ask for design details, such as a drawing, before work starts (see The next step ). As the client you still have legal responsibilities under the WAHR to ensure that the work is properly planned. Whilst you’re not expected to be an expert, insisting on information in advance should be enough to demonstrate that you fulfilled your duties.

For a link to the HSE’s microsite on scaffold design, visit http://tipsandadvice-healthandsafety.co.uk/download (HS 18.22.04).