Manually erecting heavy trusses or frames can cause serious health and safety risks – with the potential for life-altering injuries.
Three workers attempted to raise a frame by hand, with no mechanical or other devices. Two of them could not support the weight, they let go and the frame fell onto the third worker – who is now paralysed.
In a near-identical case involving three workers walking up a frame, two let go and the frame fell on the third. He now has a permanent back injury.
After having a roof truss lifted onto the frame by a crane (which then left), two workers attempted to move a roof truss along the frame by hand. The truss toppled and knocked the worker to the ground. He is paralysed.
These incidents highlight the risks when tasks are poorly planned – resulting in absent or ineffective risk controls.
Installing or adjusting frames or trusses has several risks including:
- the heavy weight involved
- the high centre of gravity and inherent instability, and (in some cases)
- working at heights.
There are several points where something can go wrong, and a chance the frame or truss could fall before it is secured.
Risks can be reduced by
- planning how the work will be carried out safely
- involving workers in the discussion or task analysis of how the trusses will be installed safely
- taking advantage of readily available mechanical equipment such as cranes to assist in installing trusses.
Further minimisation controls include ensuring:
- the team responsible for the erection of trusses have the experience and training
- that the work is supervised by a competent person.
If the use of a crane is not reasonably practicable then risk of harm can be minimised by:
- using an adequate number workers to install the trusses, so the heavy trusses aren’t left to be handled by an inadequate number of people
- have adequate scaffolding and safety netting properly installed to enable trusses to be placed and secured safely. Planning how the trusses will be erected and braced.
The following standards are relevant:
- AS/NZ 4389 Roof safety mesh
- AS/NZ 1576 Scaffolding
- AS 4440-2004
- BS EN 1263 Safety nets