Service Truck Crane Operator 4 Flashcards

A service truck crane is positioned with outriggers fully extended. The load chart shows a 4,200 lb capacity at 14 ft radius. The operator intends to lift a 3,800 lb load but the rigging assembly weighs 320 lb. The boom is rotated to the rear quadrant, which has a 90% capacity derating factor for this unit. What is the maximum net load the operator can safely lift in this configuration?

Answer: The lift is not permissible because total load (4,120 lb) exceeds the derated capacity of 3,780 lb

The rated capacity in the rear quadrant is 4,200 lb × 0.90 = 3,780 lb. This 3,780 lb must cover the entire suspended load, which includes both the 3,800 lb net load AND the 320 lb rigging assembly, totaling 4,120 lb. Since 4,120 lb exceeds the 3,780 lb derated capacity, the lift is not permissible as configured.

During a pre-shift inspection, a service truck crane operator discovers a hydraulic cylinder on the main boom has a slow but consistent external oil leak from the rod seal. There is no load on the crane. Under NCCCO and ASME B30.22 standards, what is the correct immediate action?

Answer: Remove the crane from service and notify the person responsible for the equipment before operating

ASME B30.22 requires that any hydraulic system malfunction, including leaking cylinders, that affects safe operation must result in the crane being removed from service immediately. The operator must notify the person responsible for the equipment. A leaking hydraulic cylinder can cause uncontrolled boom descent under load, making any operation unsafe regardless of load percentage.

A crane operator is calculating outrigger pad size requirements. The service truck crane exerts 28,000 lb on each outrigger float during the critical lift. The soil bearing capacity at the site has been assessed at 1,500 lb/ft². What is the MINIMUM pad area required per outrigger, and which value should a competent person use when actual soil data is unavailable?

Answer: Minimum 18.67 ft² per pad; when soil data is absent, assume the worst-case default of 1,000 lb/ft²

Pad area = outrigger load ÷ soil bearing capacity = 28,000 ÷ 1,500 = 18.67 ft² minimum. When actual soil bearing capacity is unknown, industry best practice and many jurisdictions require using a conservative default of 1,000 lb/ft² (or less) to account for unknown subsurface conditions, disturbed soil, buried utilities, or prior excavation — not 1,500 or 2,000 lb/ft², which could dangerously undersize pads.

An operator is using a service truck crane to lift a load using a single-part line with a wire rope that has a catalog breaking strength of 19,800 lb. The applicable design factor per ASME B30.22 for this application is 3.5. During the lift, the operator must also account for a 12% efficiency loss due to wire rope running over a sheave. What is the correct working load limit (WLL) of this reeving configuration?

Answer: 5,657 lb

First calculate the WLL based on design factor: 19,800 ÷ 3.5 = 5,657 lb. The sheave efficiency loss applies to the mechanical advantage calculation in multi-part reeving, not to the wire rope's WLL itself in a single-part line configuration. The 12% sheave loss would affect capacity in multi-part systems when calculating the hook load from drum pull. Therefore, the WLL of this single-part line is 5,657 lb.

A service truck crane operator is working near energized overhead power lines rated at 115 kV. The operator has not obtained formal line voltage confirmation from the utility. Under OSHA 1926.1408 and the 'Table A' default clearances, what minimum approach distance must be maintained, and what additional precaution is specifically required before reducing this distance?

Answer: 20 ft minimum when voltage is unknown or unconfirmed; distance may only be reduced after obtaining written confirmation of voltage AND utility owner consent to encroach

Under OSHA 1926.1408 Table A, when voltage is unknown or unconfirmed, the required clearance is 20 ft. To reduce below Table A distances, the operator must first obtain the line voltage in writing from the utility owner/operator AND receive their consent to work closer. A spotter, JSA, or safety observer alone does not authorize closer approach — the utility must be involved.

While inspecting a service truck crane's wire rope, an operator finds a segment where the rope outer wires show a 'corkscrew' or 'kinking' distortion over a 12-inch section, even though the rope is not visibly broken. The rope otherwise has no visible broken wires. What is the correct determination under ASME B30.22?

Answer: The rope must be removed from service because kinking is a disqualifying deformation regardless of broken wire count

ASME B30.22 lists kinking as one of several physical deformations — along with bird-caging, core protrusion, and severe corrosion — that require immediate rope removal from service, independent of broken wire counts. Kinking permanently damages the rope's internal geometry, redistributes stresses unevenly, and dramatically reduces load-bearing capacity in ways that are not visible externally. Broken wire criteria are a separate and additional disqualifier.