Crane Safety and Pre-Operation Inspection Flashcards

During a pre-operation inspection, you discover that the load line has a section where 4 randomly distributed broken wires are found within one lay length, along with a visible kink. Per ASME B30.2, what is the correct course of action?

Answer: Remove the wire rope from service immediately — either condition alone is sufficient cause for removal

Under ASME B30.2, wire rope must be removed from service if it exhibits either 6 or more randomly distributed broken wires in one lay length OR a kink. Since both a kink AND broken wires (even fewer than 6) are present simultaneously, the rope must be removed immediately. A kink is a permanent deformation that cannot be safely used regardless of broken wire count.

A mobile crane is being set up on a jobsite where the ground bears a load of 3,200 lbs/ft². The outrigger float reaction force calculates to 180,000 lbs. The float pad area is 36 square inches. What minimum timber cribbing area (in square feet) is required to keep ground bearing pressure at or below the soil's rated capacity?

Answer: Approximately 56 sq ft

Required area = Force ÷ Allowable pressure = 180,000 lbs ÷ 3,200 lbs/ft² = 56.25 sq ft. The 36 sq in float pad only provides 0.25 sq ft of bearing area, which is grossly insufficient. Cribbing must spread the load to meet the soil's rated bearing capacity. This is a critical pre-operation ground condition check.

While performing a pre-shift inspection, an operator notices the load moment indicator (LMI) self-test completes successfully, but the device consistently reads 5% lower than the independently calculated load moment. What is the MOST appropriate action?

Answer: Remove the crane from service until the LMI is recalibrated or repaired by a qualified person

An LMI that does not accurately reflect the actual load moment is a malfunctioning safety device. OSHA 1926.1416 requires that safety devices function properly before operations begin. A known 5% inaccuracy means the crane could be operated at a higher percentage of rated capacity than the operator realizes, creating an unacceptable risk. The crane must be removed from service until a qualified person repairs and recalibrates the device.

A crane operator is inspecting the boom hoist drum and finds that when the load line is at maximum boom extension, only 1.5 wraps of wire rope remain on the drum. ASME B30.5 specifies a minimum number of wraps. What should the operator do?

Answer: Remove the crane from service — ASME B30.5 requires a minimum of 2 wraps on the drum at all times

ASME B30.5 requires a minimum of 2 wraps of wire rope on the drum when the load block is in its lowest operating position. This ensures the rope anchor's mechanical dead-end is never subjected to load — the dead-end attachment is not rated to carry the working load. With only 1.5 wraps, the crane does not meet this standard and must be removed from service.

During pre-operation inspection of a lattice boom crawler crane, the operator finds a main chord member with a visible lateral bow of 0.5% of its unsupported length. The chord is 20 feet long. What does this measurement indicate, and what action is required?

Answer: The bow equals 1.2 inches — exceeds the ASME B30.5 discard threshold of 0.5% and the boom must be removed from service

0.5% of 20 feet (240 inches) = 1.2 inches of lateral bow. Per ASME B30.5, a chord member with a bow exceeding 0.5% of its unsupported length is a discard criterion — the boom must be removed from service for inspection and repair by a qualified person. Reducing capacity is not a permitted workaround for structural deformation of boom members.

An operator conducting a pre-operation inspection on a hydraulic telescoping boom crane notes that the load chart specifies ratings for 'on rubber' and 'on outriggers — fully extended.' The job requires outriggers extended to only 60% of their full extension to clear an obstruction. Which load chart column applies?

Answer: The crane cannot be used in this configuration — no valid load chart exists for partially extended outriggers unless the manufacturer provides one

Unless the manufacturer's load chart explicitly provides ratings for partially extended outriggers, no valid rated capacity exists for that configuration. Interpolating between columns or using another column's ratings would be guessing, not engineering. OSHA 1926.1416 and ASME B30.5 require that operations be conducted within the manufacturer's documented ratings. The operator must either reconfigure to use fully extended outriggers or obtain written authorization and capacity data from the manufacturer.