LFT/General/TBT-LFT-027
Load Weight Verification and Calculations
Lifting Operations › General › Load Weight Verification and Calculations
Toolbox Talk
Load Weight Verification and Calculations
Knowing the exact weight of a load before lifting it is fundamental to safe crane operations. Overloading a crane beyond its rated capacity is the most common cause of crane collapse and dropped loads. Estimated weights are unreliable; loads must be verified from manufacturer data, delivery notes, or calculation. This talk explains how to verify load weights and why guessing is never acceptable.
Key Hazards
Crane overload and collapse from lifting loads heavier than the rated capacity
Sling and shackle failure from loads exceeding the safe working load of accessories
Uncontrolled load drop causing fatal crush injuries to workers below
Crane structural damage from repeated overloading degrading boom integrity
Control Measures
- Obtain the load weight from the manufacturer's data sheet, delivery ticket, or design drawings.
- Calculate the weight of fabricated items using material density and measured dimensions.
- Add allowances for lifting accessories, water absorption, frozen material, and formwork attachments.
- Verify the total lifted weight against the crane's load chart at the required radius and configuration.
- Never estimate a load weight; if the weight is unknown, weigh it using a calibrated load cell.
- Include the weight of all lifting accessories (slings, beams, shackles) in the total load calculation.
- Record the verified load weight in the lift plan and brief the crane operator before the lift.
- Refuse to lift any load whose weight cannot be confirmed to the appointed person's satisfaction.
- Check that the ground bearing capacity can support the crane at the planned outrigger loads.
Remember
- Never estimate or guess a load weight; always verify it from data sheets or by calculation
- Include the weight of all slings, shackles, and lifting beams in the total load calculation
- Check the verified weight against the crane load chart at the actual working radius
- Add allowances for water absorption, ice, and any attachments that increase the lifted weight
- Refuse to lift any load whose weight cannot be confirmed before the operation begins
Applicable Legislation: LOLER 1998 · BS 7121 (Code of Practice for Safe Use of Cranes) · CDM 2015 · PUWER 1998
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