Dogging (DG) key terms

The maximum load a sling, shackle, or lifting accessory is rated to lift under normal conditions, marked by the manufacturer and never exceeded during a lift.

The ratio between a component's breaking strength and its working load limit, providing a margin against failure from wear, shock loading, or calculation error.

The load at which a sling or fitting fails completely, determined by testing or calculation and used to derive the working load limit through division by the safety factor.

A test load applied to lifting equipment, usually greater than the working load limit but below breaking strength, to confirm it performs correctly before use.

The load a crane, hoist, or lifting point is designed and certified to handle in a stated configuration, often reduced as radius or reeving changes.

A manufacturer-supplied table or graph showing the permissible load at each radius, boom length, and configuration for a specific crane or hoist.

The angle measured between a sling leg and the horizontal load surface, which determines how much tension each leg carries relative to the vertical load.

The angle between two opposing sling legs in a two-leg bridle, measured at the hook, which increases leg tension as it widens.

The actual force carried by an individual sling leg, calculated from the load weight, number of legs, and sling angle, and checked against that leg's working load limit.

The portion of a total load carried by one sling leg or lifting point, which depends on the geometry of the rigging and the position of the centre of gravity.

The point where the total weight of an object is considered to act; the hook must sit vertically above it for the load to hang level and stable.

The condition in which a lifted load hangs level and stable because the hook is directly above its centre of gravity and sling legs share load appropriately.

A lift in which the load is raised straight up and down, keeping the hoist line plumb over the centre of gravity to avoid swinging or side loading.

A force applied to a sling, shackle, or crane boom in a direction other than its designed axis, which can drastically reduce capacity or cause failure.

The correct alignment of a shackle so the load acts along its pin and body axis, avoiding bending or eccentric forces that reduce its rated capacity.

Padding, sleeving, or softeners placed between a sling and sharp or abrasive load edges to prevent cutting, wear, or damage to the sling material.

A documented pre-use and periodic check of slings for cuts, broken wires, chemical damage, distorted fittings, or missing tags before any lift proceeds.

The process of checking lifting equipment against rejection criteria and confirming a legible identification tag showing capacity and inspection status is present.

Components such as shackles, hooks, swivels, eye bolts, and master links used to connect slings to loads and lifting machines, each with its own rating.

A rope attached to a load and controlled by a person on the ground to restrain rotation and swinging, keeping the load clear of obstructions and people.

The dogger's management of a load's movement, orientation, and stability throughout the lift, using tag lines, guide ropes, and clear signals.

The marked area beneath and around a suspended load where people are prohibited from standing or passing, protecting them from falling loads or swing.

A load or component that falls during lifting, usually caused by rigging failure, load shift, or incorrect attachment, and a primary hazard the exclusion zone addresses.

Movement of a load's weight or contents during a lift that changes the centre of gravity and can overload slings or cause sudden swinging.

Rotation of a load away from horizontal during lifting, often indicating the hook is not above the centre of gravity or sling lengths are unequal.

Rotating the crane or hoist about its vertical axis to move a load horizontally, a motion that must be controlled to limit swing and load drift.

A licensed or certified worker who selects, attaches, and directs slings and lifting gear, calculates load weight, and controls the load during lifting operations.

A person who prepares and assembles rigging systems, including slings, hardware, and lifting points, often working alongside the dogger during complex lifts.

The person appointed to plan, coordinate, and supervise a lifting operation, including briefing the team, confirming roles, and authorising the lift to start.

A documented method describing the loads, equipment, personnel, sequence, hazards, and controls for a lifting operation, required for complex or high-risk lifts.

A structured review identifying hazards of a lift, estimating their likelihood and consequence, and recording controls before work begins.

A ranked approach to managing risk, from eliminating the hazard through substitution, engineering controls, administrative measures, down to personal protective equipment.

Worn items such as helmet, gloves, high-visibility clothing, and safety footwear that protect the dogger from injury but sit lowest in the control hierarchy.

A short meeting before a lift where the plan, roles, signals, hazards, and emergency arrangements are explained and questions are answered by all involved.

Agreed hand and arm movements used to direct crane operators, such as raise, lower, stop, and emergency stop, understood by all parties on site.

The designated individual who relays directions to the crane operator by hand signals, radio, or other means, and is the only person authorised to do so.

Two-way voice contact between the dogger and operator, using agreed channels and phrases, with a fallback to hand signals if the link fails.

A loss or breakdown of signals between dogger and operator, which requires the operator to stop the lift until clear communication is restored.

A recognised signal or action that halts all crane movement immediately, used when a person is endangered or the load becomes unstable.

Someone with the training, qualification, and experience to perform a task safely, such as inspecting equipment or planning a lift, as required by regulation.

The legal obligation of employers and workers to take reasonable steps to protect the health and safety of themselves and others affected by their work.