NCCCO LBC key terms

The force a crane's tracks or supporting mats push into the soil, stated as weight per unit area, such as pounds per square foot. It must stay below the soil's capacity to prevent settlement, shifting, or tipping.

The maximum pressure a soil or a built-up support can carry without failing, sinking, or shifting. Site ground conditions are compared with crane ground bearing pressure to confirm the setup is safe.

Wood, steel, or composite pads placed under crawler tracks to spread the crane's weight over a wider area. Also called mats, they lower ground bearing pressure and help keep the crane level.

The condition of the crane's carbody being horizontal within the manufacturer's tolerance, often one percent or less. An out-of-level crane can lose charted capacity and tip more easily.

The visual and functional checks an operator performs on the crane before each shift, covering wire rope, hooks, brakes, indicators, and leaks. Results are documented as required by the manufacturer and OSHA.

A written plan for a particular job that identifies crane position, load weight and path, ground conditions, hazards, and the people responsible. It is prepared before work begins and reviewed with the crew.

The area swept by the counterweight and rear of the rotating upper works. It must be barricaded or marked so workers are not caught between the crane and fixed objects.

A structural device or buffer that limits how far the boom can be raised, preventing it from falling backward over the crane. It is inspected regularly and never used as a working brake.

A gauge or digital readout showing the angle of the boom above horizontal. The operator uses it, together with boom length, to determine the working radius.

Published limits, such as broken wires in a lay, wear, corrosion, kinking, or crushing, that tell you when a wire rope must be taken out of service and replaced.

A grooved pulley in the boom tip, load block, or boom hoist that guides the wire rope. Worn, cracked, or misaligned sheaves damage rope and must be repaired before use.

An instrument that senses boom length, boom angle, and load weight to calculate load moment. It warns the operator and then stops functions before the crane exceeds its rated capacity.

The maximum load a crane may lift in a stated configuration, boom length, and radius, as published in the manufacturer's load chart after all required deductions are made.

The load chart value for a given radius and configuration before deducting the weight of the hook block, slings, jib, and other attachments that count as part of the load.

Weights subtracted from the chart's gross capacity to find the allowable load, including the hook block, rigging, jib, and attached equipment. Ignoring them overloads the crane.

The horizontal distance from the crane's center of rotation to the center of gravity of the suspended load, measured with the boom and rope under load.

The turning effect of a load, calculated as load weight times its horizontal distance from the tipping axis. It grows quickly as radius increases, even when the weight stays the same.

Flexing of a lattice boom under load, which places the load at a slightly longer radius than the unloaded geometry suggests. Load charts already account for this effect.

Printed conditions on a load chart that limit or change capacities, such as areas of operation, boom length ranges, reeving requirements, or reduced travel ratings. They apply to every lift made under that chart.

A shorter boom section mounted at the main boom tip that has its own reduced capacity figures. Its weight and the loads it carries are handled according to the chart notes.

The capacity set by the strength of the crane's components, including boom, pins, wire rope, and hydraulic parts, rather than by tipping. Exceeding it can bend or break parts without warning.

The crane's resistance to tipping about its tracks or outriggers. It depends on counterweight, radius, load weight, levelness, and ground support, and it governs many chart ratings.

The number of wire rope lines running between the boom tip and the load block that share the load. More parts increase lifting capacity but reduce hoist speed.

The assembly of sheaves, frame, and hook that hangs from the boom and carries the load. Its weight is a deduction, and a heavier block reduces net capacity.

A sensing system that stops hoist-up or boom-lowering motion before the load block contacts the boom tip, preventing rope damage and a dropped load.

Pulling or dragging a load sideways, or swinging with the load hanging off-center, which puts forces on the boom it was not designed to carry. It can cause boom collapse.

A sudden application or release of load weight, such as snatching a load off the ground or letting it drop, which produces forces well above the static weight.

Traveling the crawler crane with a suspended load. It is permitted only as allowed by the manufacturer's travel chart, with the load kept low, the swing controlled, and speeds slow.

Raising or lowering the boom with the boom hoist to change the working radius. On a lattice boom crane, luffing is how the operator moves the load in and out.

The maximum wind the manufacturer allows for a lift, often lower for long booms or loads with large sail area. Gusts and sail area can make an otherwise charted lift unsafe.

Standardized arm and hand movements used to direct the operator when voice or radio communication is not used. Operator and signal person must use the same agreed signals.

The closest any part of the crane, load, or rigging may come to an energized power line, based on line voltage. It is maintained unless the line is de-energized and grounded.

Coming closer to a power line than the required approach distance, or working where the line could contact the crane. It requires the utility to de-energize or other approved safeguards.

A marked-off area around the crane's swing, load path, or other hazards that only authorized workers may enter. It protects people from being struck or crushed.

A lift meeting defined risk criteria, such as exceeding a set percentage of capacity, using more than one crane, or carrying personnel or high-value loads. It usually needs an engineered plan and added supervision.

A person who by training and experience can select, inspect, and attach rigging and determine load weights and balance. OSHA requires rigging work to be done by qualified people.

A test in which a crane or lifting component is loaded above its working load, as specified by the applicable standard, to confirm it performs safely before being placed in service.

The ratio between a component's breaking strength and its rated working load. It provides margin for wear, dynamic forces, and minor overloads; it is not a license to exceed rated capacity.