NCCCO Boom Truck flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Ground bearing pressure

Total crane and load weight divided by the outrigger pad contact area. Compare the result to the soil's allowable bearing capacity from a geotechnical evaluation before setup.

Gross load calculation

The sum of the load, rigging, slings, hook block, and all boom attachments. Gross load, not just the payload, must not exceed the chart's rated capacity.

Radius measurement point

Radius is horizontal distance from the crane's center of rotation to the center of the hoist line, measured with the load applied and boom deflection included.

Boom deflection effect

Under load, a long boom bends downward, increasing the actual radius. Verify radius with the load in the air or add the manufacturer's deflection allowance.

Outrigger chart condition

Outrigger capacity charts apply only with all beams fully extended, pads on firm level ground, and the crane level within the manufacturer's tolerance.

Tipping line

The line through the outrigger pads on the loaded side about which the crane would overturn. The load moment must stay well inside the stabilizing moment.

Anti-two-block device

A device that stops hoisting when the hook block approaches the boom tip. It must be functional and tested before each shift.

Load moment indicator

An instrument that computes load moment and warns or stops the crane when capacity is approached. A malfunctioning LMI places the crane out of service.

Hook throat opening limit

A hook must be removed from service when its throat opening increases beyond the manufacturer's limit, commonly 10 to 15 percent of the original.

Wire rope removal criteria

Broken wire counts per lay length, diameter reduction, kinking, birdcaging, heat damage, or severe corrosion require removing the rope from service per the manufacturer.

Sling leg tension formula

For a two-leg bridle, tension per leg equals half the load divided by the sine of the leg angle from horizontal. Shallow angles greatly increase tension.

Working load limit

The maximum load a rigging component is rated to carry in a specific configuration. The weakest component in the system sets the overall system capacity.

Center of gravity control

The load's center of gravity must hang directly below the hook. Off-center picks cause tilt, load shift, and uncontrolled swing during the lift.

Tag line purpose

A rope used to control load rotation and swing from outside the fall zone. It keeps personnel from touching or standing under the suspended load.

Shock loading

Sudden starts, stops, or snatching a load multiplies forces far beyond static weight. Hoist and lower smoothly to avoid exceeding rigging and chart limits.

Designated signal person

One qualified person directs the operator at a time. Anyone may give a stop signal, and the operator must obey every stop signal received.

Standard stop hand signal

Arm extended, palm down, moved back and forth horizontally. It means stop immediately and applies to any person giving it.

Loss of communication rule

If radio or hand signal communication is lost, or the load leaves the signal person's view, the operator stops all motion until communication is restored.

Critical lift definition

A lift meeting employer-defined criteria such as near-capacity loads, multiple cranes, personnel aloft, or high-consequence areas. It requires a written plan and pre-lift meeting.

Minimum approach distance

The required clearance from energized power lines set by the standard and utility owner. It must be maintained unless the line is de-energized and grounded.

Operator qualification requirement

Construction crane operators must be certified or qualified under OSHA 29 CFR 1926 Subpart CC, and certification must remain current through recertification.

Swing radius barricade

The area the counterweight and boom sweep must be barricaded to keep personnel out. Access is controlled by the lift director during the lift.

Level tolerance check

Set the crane level using a level on the crane frame within the manufacturer's tolerance, commonly one percent or less, before extending the boom.

Pick-and-carry chart

Traveling with a suspended load is permitted only if the manufacturer provides a pick-and-carry chart and the route, ground, and tire ratings are verified.

Jib and attachment deduction

Any jib, stinger, or stowed attachment mounted on the boom adds weight and changes capacity. Deduct it from the chart's rated load before comparing.

Interpolation rule

Capacity may be interpolated between tabulated radii or boom lengths, but never extrapolated beyond the chart's published values.

Pre-shift inspection scope

Check wire rope, hook and latch, sheaves, drums, brakes, outriggers, LMI, and anti-two-block before the first lift, and document any defects found.

Out-of-service tag

A defect found during inspection requires tagging the crane out of service and reporting it. It stays out until repaired and re-inspected.

Tandem lift load share

Each crane in a two-crane lift must be rated for its calculated share of the load, with a written plan and a designated lift director.

Power line contact response

If the crane contacts an energized line, the operator stays in the cab, warns others away, and avoids touching the crane and ground at the same time.

Unlevel ground effect

An unlevel crane shifts the load moment and can overload one outrigger. Use cribbing and verified level ground, never rely on the chart alone.

Rigger qualification

Under Subpart CC, riggers handling loads must be qualified by training and experience. The employer verifies and documents that qualification.