A number of soft sling failures in workplaces have occurred recently, resulting in life threatening injuries and serious near-misses.
Incorrect use of soft slings (also known as synthetic fibre slings) can result in the sudden failure of a sling, even when the load being lifted is below the working load limit (WLL) of the sling.
While soft slings are well suited to certain applications, they also have a number of limitations.
One of the most common causes of failure when using soft slings is lifting a load that has an edge with a small radius (sharp edge), rather than a rounded edge. An edge with a small radius can easily cut through a soft sling that is under load.
What may appear to be a blunt edge on a load may still be sharp enough to cut a soft sling when pressure is applied. The edge of a load only has to be relatively sharp when compared to the thickness of the soft sling in order for the sling to be cut.
Soft slings may also easily be cut by coming into contact with an obstruction while under load.
Soft slings are also more susceptible to damage than other sling types, which may cause them to fail below their WLL. Soft slings can be damaged by poor storage and handling practices, dirt and grit in the synthetic fibres, prolonged exposure to UV light (sunlight) and exposure to chemicals, grease and oil or excessive heat.
Recommended ways to control risks
Before lifting a load, a risk assessment should be conducted to decide the type of sling that is most suitable to lift the load safely, for example soft sling, chain sling.
Sling selection needs to take into consideration:
- the nature of the load, including the potential for slings to be damaged by the load’s edges or surface
- whether the load is to be lifted in a confined area and the potential for external obstructions to cause damage to the slings
- the environment the slings are to be used in (eg. heat, chemicals, dirt/dust)
- the WLL of the slings
Where a soft sling may come into contact with a relatively sharp edge of a load, appropriate cut-resistant material (for example a protective sleeve or pad) between the sling and the edges of the load should be used.
For further guidance, see AS4497:2018 Roundslings—Synthetic fibre.
Soft slings should be inspected prior to each use, and also undergo a thorough inspection at least every three months. Where slings are exposed to harsh operating or storage conditions, a more frequent inspection regime should be conducted. Inspections should be conducted by a competent person who is trained in the inspection of soft slings.
For further information about inspections see:
- AS4497:2018 Roundslings—Synthetic fibre
- AS 1353.2-1997 Flat synthetic-webbing slings
Storage and handling
Soft slings should be stored in a clean and dry location away from direct sunlight and exposure to chemicals. They should be stored off the ground on a rack or stand.
Care should be taken not to drag them along the ground which can cause abrasive damage to the synthetic fibres.
When cleaning soft slings, only use water or mild detergent and consult the manufacturer’s instructions. Never use harsh chemicals to clean a soft sling as this can cause damage to the synthetic fibres.
Under the Occupational Health and Safety Act 2004, employers must, so far as is reasonably practicable, provide and maintain a working environment that is safe and without risks to the health of employees and independent contractors. Where the risk cannot be eliminated, it must be reduced so far as is reasonably practicable.
Employers must provide or maintain plant or systems of work that are safe and without risks to health, so far as is reasonably practicable. Employers must also eliminate, or if not reasonably practicable, reduce the risk of slings failing while lifting a load so far as is reasonably practicable.
Employers must ensure employees who use soft slings are provided with information, instruction and training in the appropriate control measures to reduce the risk of sling failure including procedures for inspecting slings before use. Employers must also supervise employees as is necessary to enable the work to be done safely.
Australian Standard AS 4497:2018 Roundslings—Synthetic fibre
Australian Standard AS 1353.2-1997 Flat synthetic-webbing slings Part 2: Care and use