During any construction project, maintaining a focus on safety is mandatory and must be upheld consistently. The construction industry has witnessed a myriad of injuries and fatalities caused by misuse of scaffolding that can easily be prevented by exercising additional caution in the future.
Before anyone accesses a scaffold, it is imperative to establish the safe working load. This value will essentially dictate the number of workers, plant, and material that the scaffold can safely support while maintaining structural integrity. Exceeding this weight must be avoided at all costs to minimise the risk of the scaffold collapsing.
Calculating the Safe Working Load
The scaffold load capacity is based on 3 different weight classes that determine the load they can support:
- Light-duty scaffolds: 120kg/ square
- Medium-duty scaffolds: 240kg/ square
- Heavy-duty scaffolds: >240kg/ square
To calculate the safe working load, the following formula is used:
SWL = (Scaffold Weight Capacity / (Maximum Intended Load + Weight of Scaffold)) x Safety Factor
Where:
- Scaffold Weight Capacity is specified by the manufacturer and is visibly indicated on the scaffold itself.
- Maximum Intended Load is the total weight of workers, tools, and materials placed on the scaffold simultaneously.
- Weight of Scaffold includes the weight of the tower and its components.
- Safety Factor of 2.0 is typically incorporated to account for uncertainties in the load, although variations may exist based on specific conditions and regulations.
Factors to Consider When Determining the Safe Working Load (SWL)
While this formula may seem straightforward, ensuring precise calculations is not always guaranteed. However, there are a few factors you should consider to get as close to the real value as possible.
To calculate the safe working load, it’s important to consider dead, live, and environmental loads, all of which can affect the final value of the SWL.
- Dead loads: the weight of the tower and its components
- Live loads: the weight of the equipment, workers, and plant
- Environmental loads: wind speed or heavy rainfall
Another formula that can be used to calculate the SWL when these values are known is:
SWL = DL + 4*LL
Where:
- DL is the total value of the dead load.
- LL is the total value of the live load.
It is notable to consider that the combined weight of the scaffold and the maximum intended load should always be less than the manufacturer’s specified rate capacity. You should aim to independently perform calculations rather than relying solely on the value the manufacturer has provided.
Additionally, factors such as the levelness of the ground and the anticipated wind speed or rainfall volume on a given day can impact the scaffold’s load capacity. Scaffolds should be erected on a smooth, flat surface. In many cases where a site lacks this feature, the use of a large base plate is recommended to create an even surface to work on.
How Can We Help?
Despite a decline in rates over the years, overlooking safety remains a cause for injuries and fatalities within the construction industry. The safety factor is often underestimated by many individuals. Understanding the importance of determining the safe working load of a scaffold and ensuring this value is not exceeded is essential to maintaining secure access. To prevent such incidents and establish safe procedures on your project site, contact our team at Build Bridge today and hire experienced professionals qualified to erect scaffolds and guarantee a safe platform for your workers to complete tasks efficiently.
