NCCCO LBC flashcards

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

Outrigger Float Ground Pressure

Ground bearing pressure under an outrigger float equals the outrigger reaction load divided by the effective float or mat contact area, which must not exceed soil capacity.

Mat Load Distribution

Mats increase effective contact area, reducing ground bearing pressure; required mat area equals outrigger load divided by allowable soil bearing pressure.

Crane Leveling Tolerance

The crane must be set up level within the manufacturer's specified tolerance, commonly one percent, measured on the level indicator before lifting; outriggers fully extended and floats pinned.

Power Line Clearance Table

OSHA Table A minimum clearance is 10 ft up to 50 kV, 15 ft for 50–200 kV, 20 ft for 200–350 kV, 25 ft for 350–500 kV, and 30 ft for 500–750 kV.

Daily Pre-Shift Inspection

A documented walk-around before each shift checks outriggers, hydraulic leaks, wire rope, hooks, latches, safety devices, load moment indicator, and fire extinguisher; deficiencies are corrected before operation.

Wire Rope Removal Criteria

Remove wire rope with six randomly distributed broken wires in one lay, three broken wires in one strand of one lay, or one broken outer wire at an end fitting.

Swing Radius Barricade

The area within the rotating superstructure and counterweight swing radius must be barricaded or controlled to prevent employees from being struck or crushed during rotation.

Underground Utility Setback

Outriggers and crawler tracks must be set back from excavations, trenches, and underground utilities per the manufacturer or a qualified engineer because ground near edges can fail under crane loads.

Load Moment Definition

Load moment is the product of the load weight and its horizontal radius from the crane's center of rotation; the load moment indicator compares this value to the crane's rated moment.

Anti-Two-Block Device

A device that senses when the hook block approaches the boom tip and stops the hoist before the lines two-block, preventing rope damage and boom tip overload.

Rated Capacity Deductions

The weight of the hook block, rigging, slings, shackles, jib, and any stowed attachments must be subtracted from the gross chart capacity to determine the net permissible load.

Side Loading Prohibition

Booms are designed for vertical lifting; pulling or dragging a load sideways induces bending and can collapse the boom. Use a tag line to control rotation instead.

Hand Signal Authority

Only one designated signalperson directs the operator, but anyone may give an emergency stop signal, which the operator must obey immediately.

Pick and Carry Travel

Traveling with a load is allowed only per the manufacturer's travel chart, with the boom low, load trailing, slow speeds, and a designated spotter; never exceed travel capacity.

Personnel Platform Lift Requirements

Personnel lifting requires an approved platform, pre-lift meeting, trial lift, fall protection, and a determination that the crane and rigging are adequate; the platform must not be free to rotate.

Two-Crane Lift Plan

A multiple-crane lift requires a written plan, equal load distribution, rated capacity for each crane, a designated lift director, and coordination because load transfer changes as the load moves.

Net Crane Capacity

Net capacity equals the gross capacity read from the load chart minus all deductions, including hook block, rigging, jib, and stowed boom sections.

Radius Measurement Point

Lifting radius is measured horizontally from the crane's center of rotation to the center of gravity of the load, and it increases as the boom deflects under load.

Structural vs Stability Capacity

A load chart capacity is the lower of the boom structural limit and the crane's tipping or stability limit; the chart shows the controlling value for each radius and configuration.

Load Chart Configuration

A specific load chart applies only to a specific boom length, jib configuration, counterweight, outrigger span, and quadrant; using a chart for a different setup is unsafe.

360-Degree vs Restricted Chart

Some cranes have lower capacities over the front or rear than over the side; a 360-degree chart may not apply unless the crane is configured and rated for full rotation.

Interpolation of Chart Values

When the actual radius falls between chart radii, use the next lower capacity or linear interpolation only if the manufacturer permits it; never round up to a higher capacity.

Jib Capacity Reduction

Jib capacities are substantially lower than main boom capacities because the jib reduces structural strength and increases the load moment at a given radius.

Range Diagram Use

A range diagram shows the boom length and angle combinations that reach a given radius and height, and it is used with the load chart to verify the lift geometry.

OSHA Crane Standard

OSHA 29 CFR 1926 Subpart CC governs cranes and derricks in construction, covering ground conditions, inspections, operator certification, power line clearance, and lift planning.

ASME B30.5 Scope

ASME B30.5 establishes safety requirements for mobile and locomotive cranes, including load charts, inspections, operator aids, and operating practices referenced by OSHA.

Frequent Inspection Interval

Frequent crane inspections are required monthly to quarterly depending on severity of use, while periodic inspections are required annually; both must be documented and deficiencies corrected.

Sling Tension Formula

For a symmetrical two-leg sling, tension per leg equals half the load divided by the sine of the angle from horizontal; lower angles dramatically increase tension.

Sling Angle Factor

The load angle factor multiplies the share of load carried by each sling leg; at 30 degrees from horizontal each leg carries the full load, and at 60 degrees about 0.577 times the load.

Operator Certification Requirement

Construction crane operators must be certified by an accredited organization or qualified under OSHA 1926.1427, and the employer must ensure the operator is evaluated and trained.

Fall Protection on Crane

Employees on a crane more than 15 feet above a lower level must be protected from falls by guardrails, safety nets, or personal fall arrest systems per OSHA.

Lockout Tagout Energy Control

Before maintenance or repair, the crane must be shut down, energy sources locked out and tagged, and stored hydraulic or electrical energy released to prevent unexpected startup.