Below-the-Hook Lifting Devices
Below-the-hook devices attach between the hook and the load: spreader bars, lifting beams, vacuum lifters, lifting magnets, plate clamps and pallet forks. Each one has its own capacity and failure modes.
- Construction
- General Industry
Photo: spreader bar lifting a long load with a rated capacity tag visible
Requirements
- Rated load marked on the device; never exceed it
- Designed and built to recognized standards (ASME B30.20 / BTH-1); custom devices designed by a qualified person
- Inspected before each use and periodically, with records
- Operators trained on the specific device
Markings to look for
- Manufacturer’s name and contact information
- Serial or identification number
- Rated load (capacity)
- Weight of the device itself, if it’s heavy enough to matter
- For newer devices, the ASME BTH-1 design category and service class
Remember that the device’s own weight counts toward the crane’s load. A 2,000-pound spreader bar uses 2,000 pounds of the crane’s capacity before the load is even attached.
Inspections
| Inspection | When | Who |
|---|---|---|
| Pre-use visual check | Before each use | The user |
| Frequent inspection | Daily to monthly, depending on how hard it’s used | Designated person |
| Periodic inspection | Every 1 to 12 months, with written records | Qualified or designated person |
Look for cracked welds, bent or worn parts, damaged pins and hooks, missing markings, and (for vacuum and magnet lifters) damaged pads, poles, cables and controls. Remove damaged devices from service.
Device-specific hazards
- Vacuum lifters: loss of vacuum from power or pump failure, dirty or porous surfaces. Check the gauge and warning alarm.
- Lifting magnets: loss of power (electromagnets), thin or uneven steel, and coatings that reduce holding force.
- Plate clamps: must be the right type (vertical vs. horizontal) and locked closed before lifting.
- Spreader bars and beams: sling angles and attachment points must match the design.
- Make a short test lift and hold it before moving the load.
- Keep everyone out from under loads held by vacuum or magnets.
- Center the device over the load’s center of gravity so it lifts level.
- Check that the load is within the device’s size, thickness and surface limits (for clamps, magnets and vacuum pads).
- Use tag lines to control long loads.
- Don’t build homemade spreader bars or lifting beams from scrap pipe or beams.
- Don’t side-load a device designed for vertical lifts.
- Don’t lift people with below-the-hook devices unless designed and approved for it. See Hoisting Personnel.
- Don’t turn off a permanent magnet or release a clamp until the load is fully landed and stable.
Standards & references
- ASME B30.20 and BTH-1: Below-the-hook lifting devices
- See also: ASME B30 Standards
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