CSCS Mobile Crane cheat sheet

Ground bearing pressure = total load (crane weight + counterweight + load + rigging) divided by the bearing area under each outrigger or track.

Percent of capacity = (lift load including rigging and deductions) ÷ (rated capacity for the actual radius and configuration) × 100.

Load radius is measured horizontally from the crane's rotation axis to the center of gravity of the load, not to the hook or the edge of the load.

Plan the lift so the crane's rotation axis stays a fixed distance from any obstruction; swinging a load changes radius only if the boom angle or boom length changes.

Deductions from gross capacity include jib, auxiliary head, hook block, and any stowed attachments; net capacity = gross capacity minus these deductions.

A lift plan must identify power line clearances, underground utilities, soil type, slope, and the crane's access and egress route.

Critical lift criteria commonly include exceeding 75% of rated capacity, lifting over occupied areas, or using more than one crane.

Wind area of the load increases with the square of load dimensions; a load's sail area matters more than its weight for wind effects.

Outrigger floats increase bearing area; pressure on soil = load per outrigger ÷ float area, so doubling float dimensions quarters the pressure.

Crane must be level within the manufacturer's tolerance (commonly 1% or as specified) before lifting; use a bubble level or inclinometer on the carrier.

Outriggers must be fully extended and set on firm, drained, compacted ground; cribbing must be sized to spread load, not just to level.

Boom assembly pins and pendants must be fully engaged and retaining pins installed before the boom is raised.

Counterweight must match the load chart configuration selected; removing or adding counterweight changes the rated capacity.

Assembly/disassembly area must be barricaded and controlled; only the assembly director and crew enter the boom and counterweight zone.

Boom length, jib length, and boom angle must be recorded and matched to the specific load chart before the first lift.

Electrical grounding, anemometer installation, and anti-two-block function checks are completed during setup verification.

Rated capacity is read at the intersection of load radius and boom length for the specific boom, jib, counterweight, and outrigger configuration.

Interpolate between chart values only linearly and only where the manufacturer permits; never extrapolate beyond the chart.

Capacity decreases as radius increases and as boom length increases at a given radius; a longer boom at the same radius usually reduces capacity.

On-rubber capacities are typically much lower than on-outrigger capacities and often require the boom centered over the front or rear.

Deductions: hook block, headache ball, slings, spreader bars, and jib must be subtracted from gross capacity to get allowable load.

Load chart notes govern special conditions: travel with load, pick-and-carry, personnel platforms, and multiple-part line requirements.

The number of parts of line affects capacity only through the chart's stated reeving limits; the chart already accounts for the standard reeving.

When two cranes lift a load, each crane's share depends on load geometry; common practice limits each to 75% of its rated capacity unless a qualified engineer specifies otherwise.

Sling tension in a two-leg bridle = (load ÷ 2) ÷ cos(angle from vertical); as the angle from vertical increases, tension increases.

Sling angle is measured from horizontal; a 30° horizontal angle doubles the tension compared with a vertical lift.

Working load limit (WLL) of a sling must be at least the load divided by the number of legs, adjusted for angle and any unequal loading.

Center of gravity must be under the hook; an off-center pick causes load tilt and unequal leg loading.

Shackles, hooks, and rigging hardware must be rated and match the sling capacity; hooks need a functioning latch.

Tag lines control rotation and swing but must never be used to pull a load beyond the crane's rated radius.

Softeners or edge protection are required where slings contact sharp edges; wire rope slings must not be kinked or birdcaged.

Shock loading multiplies dynamic forces; lift smoothly and avoid sudden stops that add to static sling tension.

The signalperson must be qualified and must use standard signals; any signal may be given by anyone to stop the load in an emergency.

Only one designated signalperson directs the operator at a time; a change of signalperson must be communicated to the operator.

Hand signals must be clear, distinct, and given from a position in full view of the operator; radio communication is an alternative when specified.

Standard signals: raise boom (arm extended, fingers closed, thumb up); lower boom (arm extended, thumb down); stop (arm extended, palm down, hold).

Standard signals: hoist (forearm up, index finger up, circular motion); lower (arm down, index finger down, circular motion); dog everything (clasp hands at waist).

Standard signals: swing (arm extended, point in direction of swing); travel (fists in front, circular motion in travel direction).

Emergency stop is given by anyone and requires the operator to stop immediately and hold.

Signalperson must maintain line of sight or radio contact; if contact is lost, the operator stops until communication is restored.

Smooth acceleration and deceleration limit pendulum swing; swing the boom, not the load, to control position.

Avoid side loading the boom; booms are designed for vertical loads within the chart's rated capacity.

Keep the load as low as practical and control swing with tag lines; centrifugal force increases radius during rapid swings.

Anti-two-block device prevents the hook block from contacting the boom tip; never bypass or disable it.

Load moment indicator (LMI) or rated capacity limiter warns and stops operations approaching rated capacity; operators must not override except per manufacturer procedure.

Travel with a load only per the manufacturer's travel chart, with the boom in the specified position and the load as low as possible.

Wind speed limits and load sail area govern when a lift must stop; use the anemometer reading at boom tip height.

Park the crane with the boom lowered, hook secured, and controls in neutral; set brakes and remove the key.

Pre-shift inspection covers wire rope, hook, rigging, outriggers, levels, LMI, anti-two-block, brakes, and fluid levels.

Wire rope removal criteria include broken wires per lay, diameter reduction, corrosion, kinking, and birdcaging per the manufacturer or standard.

Hook inspection: check for cracks, throat opening increase (commonly 15%), wear, and latch function.

Periodic inspections are required at intervals (commonly monthly to annually) and after any incident, shock load, or modification.

Documented inspections must be retained; records include date, inspector, findings, and corrective action.

Hydraulic systems must be checked for leaks and cylinder condition; leaking cylinders can cause uncontrolled boom lowering.

Load moment indicator and anti-two-block must be function-tested before each shift, not just inspected visually.

Any safety device found defective removes the crane from service until repaired and re-tested.

Maintain the required minimum clearance from power lines per the applicable standard; if clearance cannot be maintained, de-energize and ground the lines.

If contact with a power line occurs, the operator should stay in the cab and warn others away; if evacuation is necessary, jump clear and shuffle away.

Barricade the swing radius and the area under the load; no personnel under a suspended load.

Emergency lowering procedures must be known: use the manufacturer's emergency pump or lowering valve per the manual.

Fire extinguisher must be on the crane and inspected; know the fuel shutoff and battery disconnect locations.

Load drop or tip-over response: stop operations, secure the area, notify supervision, and do not re-enter until assessed.

Personnel platforms require the manufacturer's approval, a fall protection system, and reduced capacity per the platform chart.

Wind, lightning, and severe weather require stopping the lift and lowering the boom per the manufacturer's storm procedures.