Red Seal Mobile Crane Operator flashcards

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

Competent operator definition

A person with training, qualification, and experience who also knows the hazards of the work and the equipment. Certification alone does not make an operator competent; the employer must verify the combination.

Right to refuse unsafe work

A statutory worker right in most Canadian jurisdictions. The worker reports the hazard, the employer investigates with the worker present, and the refusal stands until the hazard is resolved.

Minimum approach distance

The closest a crane, boom, load, or rigging may come to an energized overhead line. It varies with voltage and jurisdiction; otherwise de-energize, ground, or use a written limit-of-approach procedure.

Hierarchy of controls

Eliminate, substitute, engineer, administrate, then PPE. PPE such as high-visibility clothing and hard hats is the last line of defence, not the primary control for a crane hazard.

Load angle factor

A multiplier converting load to sling tension based on angle from horizontal: 60° = 1.155, 45° = 1.414, 30° = 2.000. Sling tension equals load times factor divided by the number of legs.

Working load limit

The maximum load a sling or rigging component may carry in a stated hitch. It equals breaking strength divided by the design factor, commonly 5:1 for wire rope and 4:1 for chain.

Choker hitch reduction

A choker hitch reduces a sling's vertical rating to roughly 75-80%, because the choked sling grips itself and the load is carried on a smaller effective section. Always use the manufacturer's chart.

Center of gravity and tension

When the center of gravity is off-center, the nearer pick point carries more tension. Tension divides inversely with horizontal distance from the center of gravity to each point.

Ground bearing pressure

Total weight of crane, counterweight, and load divided by total outrigger or track contact area. Compare it to the geotechnical allowable bearing capacity, not to how firm the surface looks.

Outrigger reaction

The actual load on one outrigger float, which exceeds the average because load is distributed unevenly. Use the manufacturer's published maximum reaction for each configuration when sizing cribbing.

Cribbing sizing rule

Float load divided by cribbing contact area must stay below the soil's allowable bearing capacity. Cribbing must be level, full-contact, and stacked with the grain of each layer crossed.

Crane level tolerance

Typically one percent of grade, or the manufacturer's stricter figure. Outriggers must be fully extended and floats pinned before lifting; an out-of-level crane loses capacity and can tip.

Pre-use inspection

The operator's walkaround at the start of each shift: wire rope and sheaves, hook and latch, rigging, outriggers, leaks, alarms, limit switches, and the load moment indicator. Defects are reported and tagged.

Periodic inspection

A documented inspection by a qualified inspector, commonly annual, covering structural and mechanical condition. It is separate from the operator's daily pre-use check and must be recorded and retained.

Anti-two-block device

A safety device that stops hoisting before the hook block contacts the boom tip. It must be functional and never bypassed; a defeated device is a critical defect and the crane is out of service.

Hook rejection criteria

Reject a hook with cracks, deformation, a throat opening beyond the manufacturer's limit (commonly 10-15%), a worn saddle beyond 10%, or a missing or malfunctioning safety latch.

Radius measurement

The horizontal distance from the crane's center of rotation to the center of the hook, not to the boom tip. Adding a jib or changing quadrant changes the radius and therefore the rating.

Structural versus stability limits

Structural limits are based on component strength; stability limits are based on tipping. On outriggers, structural limits usually govern at short radius and stability limits at long radius.

Quadrant rating

Capacity over the front, side, and rear of the carrier may differ because the undercarriage and outriggers support the crane differently. Use the chart for the quadrant where the boom actually works.

Swinging load effect

Starting or stopping a swing abruptly lets the load trail outward, increasing radius and reducing capacity, and adds side load to the boom. Use smooth control and avoid rapid swing changes.

Two-crane lift rule

Requires a written plan and a designated lift director. Unless engineered otherwise, each crane should not exceed 75% of its rated capacity for its share of the load.

Assist crane capacity check

During assembly, verify the assist crane's rating at the actual radius for the actual boom or jib weight, deducting the hook block, slings, and any below-the-hook device from the chart.

Boom pin keepers

Pins connecting boom sections must be fully engaged with keepers or cotter pins secured. A missing keeper is a critical defect that can allow the boom to separate under load.

Partial counterweight hazard

Installing less counterweight than the chart specifies changes the crane's stability and invalidates the rating. Counterweight must be installed in the specified quantity and sequence.

Transport permit requirements

Oversize or overweight crane loads need permits from the road authority, and axle and gross weights must stay within legal limits. Load securement must meet the jurisdiction's standard.

Designated signal person

One person is appointed to direct the operator. Anyone may give a stop signal, and the operator must obey it. The operator stops whenever a signal is unclear or lost.

Blind lift signalling

When the signal person cannot see both the load and the landing zone, a relay signal person is added so commands pass clearly between the operator and the final position.

Radio communication protocol

Identify the crane and signal person, keep phrases brief and clear, and confirm critical commands. A dedicated channel prevents cross-talk when several cranes work on the same site.

Load chart selection

The chart must match the crane's serial number, boom configuration, jib, and counterweight. Using a chart for a different configuration is a leading cause of overload and tip-over.

Net capacity calculation

Start with the gross capacity at the actual radius and quadrant, then deduct the hook block, slings, and any below-the-hook device. The remainder is the load that may be lifted.

Lift plan contents

Load weight and center of gravity, rigging and sling angles, crane position and chart page, ground bearing check, power line hazards, and the communication and signal plan.

Records retention

Keep pre-use and periodic inspection reports, maintenance and repair records, load test certificates, operator certification, and lift plans current and available on site for the regulator.