Site Hazards & Risk Assessment Flashcards

A crane is operating near a live 69 kV overhead power line. After accounting for the minimum approach distance required by OSHA 1926.1408, the operator notices that wind gusts are causing the boom tip to sway approximately 2 feet laterally. What is the MOST appropriate action?

Answer: Increase the established clearance buffer beyond the minimum approach distance to account for boom sway

OSHA 1926.1408 establishes minimum approach distances as absolute minimums, but crane operators and employers must assess site-specific conditions — including wind and boom sway — and establish greater clearances when dynamic conditions increase encroachment risk. Waiting until the boom physically enters the MAD zone is reactive and potentially fatal; the standard requires proactive hazard assessment.

During a pre-lift site hazard assessment on a brownfield site, the operator discovers that the crane will be positioned over a former underground fuel storage tank that was reportedly decommissioned 15 years ago. Soil borings taken 6 months ago showed no anomalies. What is the CORRECT course of action before positioning the crane?

Answer: Require a qualified engineer to reassess subsurface conditions given the known underground void history before crane placement

Decommissioned underground tanks represent an ongoing subsurface void and structural uncertainty risk. Soil borings from 6 months prior may not reflect current conditions — corrosion, groundwater infiltration, or incomplete fill could create voids. ASME B30.5 and NCCCO standards require a qualified engineer to evaluate ground conditions when known subsurface hazards exist, regardless of prior testing. Pad size and radius reduction do not substitute for engineering evaluation of an unknown void.

A crane operator is preparing to conduct a pick in a confined industrial yard. The lift plan specifies outriggers fully extended. Upon arrival, the operator finds that one outrigger on the rear-left cannot fully extend due to an unmarked subsurface obstruction, leaving it at 78% extension. The job superintendent says to proceed using the fully-extended load chart and offset with a heavier counterweight. What should the operator do?

Answer: Refuse the lift until the manufacturer's load chart for the actual outrigger configuration is obtained or the obstruction is resolved

Load charts are valid only for the specific machine configurations defined by the manufacturer. Operating with a partially extended outrigger while using the fully-extended chart is a direct violation of ASME B30.5 and OSHA 1926.1416. Adding counterweight does not compensate for reduced ground bearing area or altered stability geometry. The operator must either resolve the obstruction, obtain manufacturer-approved capacity data for the actual configuration, or refuse the lift. A superintendent's direction does not override the operator's authority and responsibility.

During a risk assessment for a critical lift over an occupied building, the safety team calculates that the load path passes over a roof section where workers are present. The lift plan calls for workers to evacuate the roof during the pick. Just before the lift begins, the signal person reports that two workers are still visible on the far end of the roof but are outside the calculated load drop zone. What is the MOST appropriate action?

Answer: Halt the lift until all personnel are fully clear of the entire roof, not just the calculated drop zone

Drop zone calculations are estimates based on ideal failure modes and cannot account for all failure scenarios (e.g., rigging failure at a different point, load rotation, structural collapse propagation). NCCCO and ASME B30.5 require exclusion zones to be maintained for all personnel under or in the vicinity of suspended loads. Worker acknowledgment of risk does not create a legal or safe exemption. The lift must be halted until all personnel are clear of the entire hazard area.

A crane is operating on a barge in a tidal waterway. The operator completed a site hazard assessment at 0700 when the tidal current was 0.5 knots. By 1400, the current has increased to 2.8 knots due to tidal change, affecting barge stability and introducing lateral load on the suspended load. The lift plan does not address variable tidal conditions. What action is REQUIRED?

Answer: Suspend operations and reassess — changed site conditions that exceed those addressed in the lift plan require plan modification before proceeding

A lift plan is valid for the conditions it was designed to address. When site conditions materially change — in this case, a nearly 6x increase in tidal current affecting barge trim, mooring loads, and lateral forces on the load — the lift plan must be reassessed by a qualified person before operations continue. OSHA 1926.1412 and ASME B30.5 require that changes to conditions affecting safety trigger a reassessment. Mooring line design capacity is a separate analysis and does not address dynamic load shifts on the crane.

A crane operator is conducting a hazard assessment before a pick near an active roadway. The site safety plan specifies a spotter to manage traffic, but the spotter must simultaneously serve as the signal person for the lift. ANSI/ASME B30.5 and OSHA 1926.1419 signal person qualifications apply. What is the PRIMARY hazard created by this dual-role assignment?

Answer: Divided attention between traffic control and crane signaling creates a critical communication breakdown risk, particularly during simultaneous events

Requiring one person to simultaneously manage vehicle traffic and provide crane signals creates a task saturation hazard — a well-documented human factors risk where dual competing demands degrade performance on both tasks, particularly during simultaneous critical events (e.g., a vehicle approaching while the operator requests a load direction signal). OSHA 1926.1419 requires signal persons to give undivided attention to their signaling duties. The NCCCO and ASME B30.5 frameworks both emphasize that communication clarity and singular focus are essential to safe crane operations. This is a role separation requirement, not a certification issue.