Boom Over a Public Walkway
A 42 m boom pump is set up beside a four-story building. The boom must reach over a public sidewalk to place concrete on a second-floor deck. The sidewalk is 2.4 m wide and has pedestrian traffic. The contractor has placed two cones and caution tape, but no covered walkway or flagger. Wind is 30 km/h sustained with 45 km/h gusts. The manufacturer's manual gives a maximum allowable wind speed of 45 km/h for this boom configuration, and company policy stops boom operation at 40 km/h sustained. The operator's view of the end hose is blocked by scaffolding; the spotter is on the deck but has no radio contact. Washout water is being dumped into a curb inlet that discharges to a storm sewer. A worker on the deck wears a hard hat but no safety glasses or gloves while handling the end hose.
1. Rank the hazards and decide whether the pour should start.
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Do not start as set up. The highest-priority hazard is the public sidewalk: cones and tape do not protect pedestrians from a boom, hose, or concrete spill. Next is the blind lift with no radio communication between operator and spotter; the operator cannot see the end hose, so signals are essential. Wind is at the manufacturer's maximum in gusts and above company policy for sustained operation if it rises further. Washout into a storm sewer is an environmental violation. Missing eye and hand protection is a serious but lower-priority PPE issue. The pour should be delayed until the public is protected, communication is established, wind is monitored against the stop limit, and washout is contained.
2. What controls should be in place before boom operation?
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Install a covered pedestrian walkway or close and reroute the sidewalk with trained flaggers, as required by the site traffic plan. Provide radio communication between the operator and a spotter who can see the end hose and the swing path. Confirm the wind speed at the boom and stop if sustained wind reaches 40 km/h or gusts approach 45 km/h. Contain washout in a lined, bermed area and dispose of it properly; do not discharge to the storm drain. Require safety glasses and gloves for anyone handling the end hose. Brief the crew on the boom swing path, exclusion zone, and emergency stop signals.
3. If sustained wind rises to 42 km/h during the pour, what should the operator do?
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Stop boom operation. Company policy sets 40 km/h sustained as the stop point, and the manufacturer's 45 km/h maximum is a limit, not a target; gusts can exceed the measured sustained value. Stop pumping, keep the boom from moving over the public area, and lower or retract the boom according to the manufacturer's procedure. Secure the pump and wait for the wind to drop and remain below the limit. Do not resume just because the gust passes; recheck the forecast and the site conditions. Inform the contractor that the pour is on hold for wind.