High Risk Work Licence - Tower Crane (CT) key terms

The ranked order for managing risk: eliminate the hazard first, then substitute, then use engineering controls, then administrative controls, with personal protective equipment as the last line of defence.

The legal obligation on a person conducting work to take all reasonably practicable steps to protect the health and safety of workers and others affected by the activity.

The legal entity, such as an employer or principal contractor, that holds the primary work health and safety duties for the site and the crane operations it controls.

A person who has acquired through training, qualification or experience the knowledge and skills to carry out a specified task safely and correctly, such as inspecting lifting gear.

The formal authorisation issued after assessment that permits a person to operate a specific class of plant, such as a tower crane, in the jurisdiction where it is issued.

A written document that sets out the work activity, the hazards identified, the control measures to be applied and how those controls will be implemented, monitored and reviewed.

The structured process of identifying hazards, evaluating the likelihood and consequence of harm, and deciding which controls are needed to reduce risk to an acceptable level.

A defined ground area beneath and around the crane that unauthorised people are kept out of, for example during lifting, slewing or when a suspended load could fall or drift.

Physical barriers, tape, fencing or signage used to mark and enforce an exclusion zone so that people cannot enter a hazardous area without authorisation.

A slewing jib crane mounted on a fixed or travelling base, with a vertical mast, a horizontal jib and a counter-jib, used to lift and place loads over a wide radius on construction sites.

The vertical lattice tower section of a tower crane that supports the slewing unit, jib and loads, and is built up from interchangeable sections bolted or pinned together.

The horizontal working arm of a tower crane along which the trolley travels, carrying the hoist rope and load at a radius measured from the slewing centre.

The short rear arm opposite the jib that carries the counterweights and often the hoist machinery, balancing the crane and reducing the overturning moment created by the load.

Heavy blocks fixed to the counter-jib to balance the crane; their number and position must match the manufacturer's configuration for the jib length and height in use.

The bearing and drive assembly at the top of the mast that allows the jib and counter-jib to rotate about the vertical axis, usually driven by an electric motor and gearbox.

The wheeled carriage that runs along the jib and carries the hoist rope and hook block, moving the load in and out to change the load radius.

The horizontal distance from the centre of slewing to the centre of the load, which determines the crane's rated capacity and must be checked against the load chart.

The manufacturer's table or graph giving the maximum safe load for each combination of radius, jib configuration and sometimes wind or duty condition, used to plan every lift.

The maximum load a crane may lift at a given radius and configuration under the manufacturer's stated conditions, before any deductions for lifting gear or hook block.

The maximum mass that a single item of lifting gear, such as a sling or shackle, is designed and rated to support in a specified configuration.

The process of calculating the total mass to be lifted, including the load, slings, spreader and hook block, and comparing it with the rated capacity at the working radius.

The point at which the whole mass of an object is considered to act; the hook must sit vertically above it so that the load hangs level and does not tilt or swing.

The angle between a sling leg and the horizontal or vertical; as the angle from the vertical increases, each leg carries a greater share of the load and the tension rises.

A flexible lifting component such as chain, wire rope or synthetic webbing that connects the load to the hook and is rated for a stated working load limit.

A U-shaped metal connector closed by a pin or bolt, used to join slings, hooks and fittings, and selected by size, pin type and rated working load limit.

A record listing each item of lifting equipment, its unique identification, working load limit and inspection history, so that damaged or out-of-date gear can be traced and removed.

The checks carried out before each shift or use, covering the crane's structure, ropes, brakes, limits, warning devices and the surrounding site, with defects recorded and reported.

A test of the crane's motions and safety devices, such as hoist, slew, trolley and limit switches, carried out in a safe area before the crane is used for lifting.

A device that automatically stops a crane motion, such as hoisting up, trolleying out or slewing, before it reaches a dangerous position or end of travel.

A safety device that senses the load and radius and prevents the crane from being operated beyond its rated capacity, often with a warning before the cut-out point.

The brake or holding device that controls or stops rotation of the slewing unit, allowing the jib to be held steady in wind or during a precision placement.

The controlled rotation of the crane's jib and counter-jib about the vertical axis, which must be started and stopped smoothly to prevent the load from swinging.

Moving the trolley along the jib to change the load radius, done slowly and progressively so the load does not swing or pass over people.

The pendulum movement of a suspended load caused by sudden starting or stopping of hoist, slew or trolley motions, which can strike people or structures.

A rope attached to a load and held by a person outside the fall zone to control rotation and swinging while the load is being lifted and placed.

A licensed worker who directs the crane operator by signals, selects and attaches lifting gear, and controls the load during the lift.

A worker who prepares, assembles and attaches loads and lifting gear, and who may also direct the crane, working under the direction of the dogman or supervisor.

A standardised movement of the hands and arms used to direct the crane operator when radio communication is unavailable or unsuitable, given only by the nominated signaller.

The preferred communication link between the operator and the dogman, used on a dedicated channel with clear, agreed call signs and a check made before each lift.

The designed base, such as a pad, raft, piles or ballast, that spreads the crane's loads into the ground and must match the manufacturer's specification and the site's ground conditions.

Choosing the crane's position so that its working radius, capacity, clearances, ground conditions and proximity to hazards such as powerlines and excavations are all acceptable.

The pressure the crane's foundation or outriggers exert on the soil, which must not exceed the ground's safe capacity or the crane may settle, tilt or overturn.

The crane's ability to resist overturning, maintained by correct counterweighting, adequate foundation, level ground and keeping loads within the rated capacity at the working radius.

The minimum safe distance that must be kept between any part of the crane, its load or rigging and overhead electrical conductors, as set by the operator's site rules and the electricity authority.

The maximum wind speed, measured at the crane, at which lifting or specific operations may continue; above it the crane must be stopped and the jib put into its specified free-slew or park position.

The instrument that measures wind speed at the crane, usually mounted at the top of the mast, whose readings the operator must monitor throughout the shift.

A load hanging from the crane hook; it must never be left unattended, and no person may stand or pass beneath it while it is suspended.

The sequence for ending work safely: land and secure the load, raise the hook, place controls in neutral, apply brakes, switch off and isolate power, and secure the crane against wind.

The documented actions to take in an incident such as power failure, fire, structural damage or a dropped load, including making the area safe and notifying the relevant people.

The requirement to record and notify specified incidents, such as dropped loads, contact with powerlines or near misses, to the site supervisor and the regulator as required.