The 1,850 kg Crate and the 900 mm Load Centre
A 2,500 kg capacity counterbalance truck is rated at 2,500 kg at a 500 mm load centre; the data plate also shows 2,200 kg at 600 mm and 1,900 kg at 700 mm. No attachment is fitted. You are asked to move a single indivisible crate weighing 1,850 kg, measuring 1,400 mm long by 1,000 mm wide by 1,200 mm high. The load's centre of gravity is marked 900 mm from the fork face when the crate is seated against the backrest. The only other truck available is a 3,500 kg model, but its data plate is missing and its keys are controlled by another department. The aisle is 3.6 m wide and the destination is 80 m away on sealed concrete. Your supervisor says the 2,500 kg truck 'has plenty of margin because the crate is under 2,500 kg' and wants it moved before the next delivery arrives in 20 minutes.
1. Determine whether the crate can be lifted with the 2,500 kg truck. Show your load-moment reasoning and state any assumptions.
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No - the lift is outside the truck's rating.
Use load moment = weight × distance from the fork face to the load centre:
- Crate moment: 1,850 kg × 900 mm = 1,665,000 kg·mm
- Truck rating at 500 mm: 2,500 × 500 = 1,250,000 kg·mm
- Truck rating at 600 mm: 2,200 × 600 = 1,320,000 kg·mm
- Truck rating at 700 mm: 1,900 × 700 = 1,330,000 kg·mm
The crate's moment is greater than every tabulated rating, even before considering the 900 mm actual load centre. The fact that 1,850 kg is below 2,500 kg is irrelevant: rated capacity is a weight at a stated load centre, not an absolute weight limit. I would not extrapolate the data plate to 900 mm because capacity curves are not linear and depend on the truck's stability and hydraulic limits. The 50 kg margin at 700 mm is also not a usable margin because the load centre is 200 mm further forward. The lift must stop until a competent person confirms capacity at 900 mm or the load is made lighter or repositioned.
2. Your supervisor insists the truck is fine. What do you do and say next?
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I would stop the job and explain the numbers, not just say 'it's unsafe'. I would show that the load moment at 900 mm is 1,665,000 kg·mm and that the highest figure on the plate is 1,330,000 kg·mm at 700 mm. I would ask for one of three controls: a truck with a confirmed rating at the actual load centre, a verified lighter load, or written capacity confirmation from the truck manufacturer or a competent engineer. I would not move the crate 'just into the aisle' as a compromise, because the overload and tipping risk exist as soon as the load is lifted. I would record the request and the supervisor's instruction in the defect or handover system, ask for the decision in writing if pressure continues, and escalate to the site manager or health and safety adviser. The legal duty not to operate unsafe work equipment sits with me as the operator as well as with the employer.
3. A 3,500 kg truck is eventually released. What must you confirm before using it for this crate?
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I would confirm the replacement truck's data plate is legible, its rated capacity at the actual 900 mm load centre, and whether any attachment changes that rating. I would verify the crate weight rather than trust the label, check the fork length and spread, and confirm the load can sit against the backrest with the mast tilted back. I would inspect the truck, test brakes, steering, horn and hydraulics, and check the route for floor condition, headroom, aisle width and pedestrians. I would keep the load low, tilt it back only enough to stabilise it, centre any side shift, and travel at walking pace. If the capacity at 900 mm is still below 1,850 kg, the larger truck is not automatically suitable and I would not lift.