NZ Certificate in Cranes key terms

The maximum load a crane, sling, or lifting accessory is rated to handle under stated conditions, set by the manufacturer and reduced where configuration or conditions require. It is never exceeded during a lift.

The load a crane can lift at a specific radius and configuration as shown in the manufacturer's load chart, before any deductions for attachments or site conditions.

A manufacturer-supplied table or graph giving permitted loads for a crane at each radius, boom length, and configuration. Operators must read the chart for the actual setup before every lift.

The horizontal distance from the crane's slewing centre to the centre of gravity of the load, measured with the boom at the working position. Increasing radius reduces capacity.

The turning effect of a load about the crane's tipping point, calculated as load multiplied by radius. It explains why capacity falls sharply as the boom is lowered or extended.

The crane's resistance to tipping or overturning under load, wind, and movement. It depends on counterweight, outrigger spread, ground bearing, and keeping within the load chart.

Mass fitted to the rear of a crane to balance the load and boom. Its amount is fixed by the manufacturer and must not be altered or removed without approval.

Extendable leg with a pad that widens a mobile crane's base and transfers load to the ground. Outriggers must be fully deployed on firm, assessed ground before lifting.

The force per unit area that outriggers or tracks impose on the ground. It must be checked against soil strength and reduced with mats or spreader pads where necessary.

A timber or steel pad placed under an outrigger or track to spread load over a larger area, lowering ground bearing pressure and reducing the risk of settlement or punch-through.

The extended length of a crane's lattice or telescopic boom in the current configuration. It affects radius and capacity and must match the setting used in the load chart.

Extending or retracting the sections of a telescopic boom. It changes boom length and radius, so capacity must be rechecked from the load chart after any change.

Rotation of the crane's upper structure about its vertical axis. Controlled slewing keeps the load steady and avoids swing-out and side loading on the boom.

Outward drift of a suspended load caused by centrifugal force during slewing or by wind. It increases radius and load moment, so it must be controlled with slow, smooth movements.

A force applied sideways to a boom or sling rather than along its designed axis. It can buckle booms and damage slings and is avoided by planning lifts and controlling load movement.

A sudden increase in force caused by jerking, snatching, or dropping a load. It can far exceed the static load and overload rigging, so lifts start and stop smoothly.

The additional force on a crane or sling caused by acceleration, deceleration, or movement of the load. Allowance for it is built into ratings but poor technique can exceed it.

The maximum mass a sling or lifting component is designed to support in a particular configuration, marked on the item. It accounts for the assembly and its intended use.

The angle between a sling leg and the horizontal, or between legs. As the angle flattens, tension in each leg rises sharply, reducing the assembly's capacity.

The force carried by each leg of a multi-leg sling, which increases as the included angle widens. It is calculated from the load and the angle to check against the leg rating.

The point where a load's mass is balanced in all directions. The hook must be positioned above it, or the load will tilt when lifted.

Distributing a load evenly across sling legs and keeping it level during the lift. Poor balance overloads individual legs and causes the load to shift or rotate.

Selecting, attaching, and configuring slings, shackles, and hardware to connect a load to the crane hook safely for the planned lift.

A U-shaped metal connector with a pin or bolt, used to join slings and lifting points. The pin must be fully seated and the shackle rated for the load.

A rope attached to a load so a person can control rotation and swing from a safe distance. It keeps hands clear of the load and helps steady it during placement.

A documented method for a specific lift covering load weight, crane setup, rigging, personnel, hazards, and contingency steps. It is prepared and approved before work starts.

A lift with heightened risk, such as near capacity, over people or plant, tandem, or with unusual loads. It requires a more detailed plan, senior approval, and extra controls.

A lift using two or more cranes to share a load. It demands a written plan, agreed load share, communication, and slow coordinated movement because load transfer between cranes is unpredictable.

A structured review identifying hazards, judging likelihood and consequence, and recording controls before a lift. It informs the lifting plan and is reviewed when conditions change.

Any source of potential harm, such as overhead lines, unstable ground, wind, or people under the load. Hazards are identified and controlled through the lifting plan.

A marked area beneath and around the lift where people are not permitted during lifting. It protects against falling loads and crane movement and is enforced by barriers or a spotter.

A trained person who slings loads, directs the crane operator with signals, and controls the load during the lift. Also called a rigger in some regions.

A person competent in preparing and attaching loads, selecting slings and hardware, and directing the lift. The role overlaps with dogger and requires verified training.

Standardised arm and hand movements used to direct a crane operator when radios fail or are unsuitable. Only one designated signaller gives signals at a time.

A signal or control action that halts crane movement immediately. Any person may give it when danger is seen, and the operator must obey without question.

An inspection of the crane before use covering fluids, tyres, brakes, ropes, limit switches, and alarms. Faults are recorded and the crane is not used until they are resolved.

Scheduled and pre-use examination of the crane and lifting gear for wear, damage, and defects. Results are logged, and defective items are tagged out of service.

Attaching a clear warning tag to defective equipment, and isolating it, so it cannot be used until repaired and cleared by an authorised person.

Isolating a crane's power source and securing it with a personal lock so it cannot be energised while maintenance or repair is being carried out.

A rope of steel strands wound around a core, used for hoisting and luffing. It is inspected for broken wires, kinks, corrosion, and wear against rejection criteria.

The maximum wind speed at which a crane may operate, set by the manufacturer and influenced by load shape and sail area. Lifts stop when the limit is reached.

The force wind exerts on the load, boom, and crane structure. Large or sheeted loads catch more wind and may need a lower operating limit or extra restraint.