In this guide, we’ll look at one particularly crucial element of scaffolding safety: how to calculate the safe working load (SWL) of scaffolding. Ensuring that the SWL is understood can ultimately mean the difference between physical harm and a job well done.
Scaffolding Load Capacity
Safe Work Australia instructs that scaffolding should be erected with the most adverse load sizes in mind and that the specific capacity limits be supplied by the scaffold’s designer, manufacturer, or supplier.
AS/NZS 1576 specifies that there are three common categories of scaffolding load. These are light-duty, medium-duty, and heavy-duty. Each is rated for its safe working load of personnel, equipment and debris.
The safe working load for these categories are as follows:
- Light-duty scaffold working load: 225kg
- Medium-duty scaffold working load: 450kg
- Heavy-duty scaffold working load: 675kg
Despite these stipulations – in some cases – it may be necessary to calculate the SWL manually.
How To Calculate Safe Working Load Of Scaffolding
When considering how to calculate the required safe working load of scaffolding, there are six main variables to look at:
1. Dead load
Dead load is the weight of a scaffold and its components before it is loaded.
2. Live load
Live load is the weight of equipment and workers on the scaffolding (per bay)
3. Static load
Static load is a load that doesn’t move.
4. Dynamic load
Dynamic load is the load/force made by a moving load, on a structure or component.
5. Wind load
Wind load is the additional load against the scaffold created by the force of wind on a structure
6. Environmental load
Environmental load is the weight of environmental factors such as debris, water, snow and dust that may be on the scaffolding
With all factors considered, scaffolding is erected and certified to a particular load capacity adequate for the project to be carried out safely.
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