Rigging, Lifting and Manual Handling
Domain focus
This domain tests rigging, lifting, and manual handling: sling and shackle selection, rated capacity, inspection, load angle, centre of gravity, lift planning, tag lines, exclusion zones, and safe lifting of loads by hand.
Core rules
- Use only certified, inspected lifting gear with a readable safe working load (SWL) or working load limit (WLL). Match the hardware to the load and the environment.
- Sling tension increases as the angle to the horizontal decreases. For a symmetric two-leg lift, each leg tension equals half the load divided by the sine of the angle to the horizontal.
- Keep the load below the hook, control the centre of gravity, use tag lines, and keep people out from under the load.
- Manual handling: assess the load, clear the path, keep the load close, bend knees, avoid twisting, and use a team lift when needed.
- Shock loading, side loading, and knotting reduce capacity. Never use a sling with a missing tag, cuts, broken wires, or distorted hardware.
Worked example
A 6-tonne load is lifted with two symmetric legs at 60° to the horizontal. Each leg carries (6 ÷ 2) ÷ sin 60° = 3 ÷ 0.866 = 3.46 tonnes. If each sling has a 4-tonne WLL, the lift is acceptable. At 30°, each leg would carry 3 ÷ 0.5 = 6 tonnes, so the same slings would be overloaded.
Traps
Using a sling at its vertical rating when it is angled; assuming two legs share load equally when the centre of gravity is off-centre; standing under a suspended load; lifting with a damaged shackle pin.