The ton rating on a crane is its maximum capacity under a specific set of conditions. It cannot lift that weight at every distance or boom height. Capacity changes with how far the load is from the crane, boom length, outrigger setup, counterweights, attachments, wind and the weight of the hook and rigging. The crane company makes the final choice from the load chart for your lift. What you can do is bring it good measurements.
The four numbers to measure
Crane Compare's rental guide uses four project dimensions:
- Load (L): the weight of what is being lifted.
- Height (H): the height of the structure near the crane operation.
- Width 1 (W1): the distance from the crane to the nearest face of the structure.
- Width 2 (W2): the distance from the structure's face to the exact center where the load will be placed.
Measure all distances with a tape measure.
Find the real weight of the load
For construction work covered by federal OSHA crane rules, the operator must verify that the load is within the crane's rated capacity. The weight can come from a source the industry recognizes, such as the load's manufacturer, or from a recognized calculation, such as a steel beam's measured length times its known weight per foot. When the operator asks for this information, it must be provided before the lift. Look for a spec sheet or shipping weight and send the number to the crane company ahead of time.
The rule also lets an operator start hoisting and use a load weighing or capacity indicating device. If the load exceeds 75 percent of the crane's maximum rated capacity at the longest radius planned for the lift, the operator must not go on until the weight is verified.
Where the crane will stand
- Check for clear and easy access to the area where the crane will be set up.
- Note the type of ground surface under the crane. The site may need heavy mats or blocking to give firm, level support.
- Report any overhead hazards, such as power lines and trees.
Power lines
Under OSHA's power line rule, if any part of the crane, the load line or the load could get closer than 20 feet to a power line, the crane employer must de-energize and ground the line, keep at least 20 feet of clearance, or use the minimum distance for the line's voltage. That distance is 10 feet for lines up to 50 kV. When the voltage is needed, the utility must provide it within two working days of the request. Tell the crane company about any power lines when you ask for a quote.
Does a bigger crane always cost more?
In the published rate sheets RiggingForce reviewed, hourly rates rise with size, from $155 to $175 for a 23 to 30 ton boom truck to $275 to $550 for a 100 to 210 ton mobile crane. A crane that cannot reach your load at the distance needed is not a saving. See How much does crane rental cost in South Carolina?
What to send when you ask for a quote
- What is being lifted, its weight and its dimensions
- Where it starts and where it has to go (H, W1 and W2)
- Ground type and truck access
- Power lines or other overhead obstacles
- Date, time window and how long the job should take
Sources
- Crane Compare, Crane Rental Services South Carolina (project dimensions and setup notes)
- OSHA, 29 CFR 1926.1417, Operation (paragraph (o), rated capacity and load weight)
- OSHA, 29 CFR 1926.1408, Power line safety (Table A and paragraph (c))
- RiggingForce, How Much Does It Cost to Hire a Crane for a Day?
General information, not safety, legal or engineering advice. The crane company's operator and lift plan decide the final crane size.