Before you unfold the boom of a pump truck on a new jobsite, be sure to check for power lines and other obstructions, excavations, and unstable ground.
The American Concrete Pumping Association requires that a pump operator keep the boom tip and any section of the boom at least 17 feet from any electric line, for any boom position needed to do the job. Even power lines farther than 17 feet from the placing area can pose a risk if they are within the boom's slewing radius. Operators should never rely on their depth perception to determine how far the boom tip is from an electric line. Instead, they should maneuver the boom using a radio or cable remote control after positioning themselves so they can clearly see the distance between boom and wires.
When pumping concrete near a cliff or into an excavation, always follow the one-to-one rule: For every 1 foot of depth, stay at least 1 foot back from the edge. For a 20-foot-deep excavation, for example, spot the pump at least 20 feet back from the edge.
To keep the pump from tipping, cribbing (if used) must be adequate and the soil it's set on must have adequate load-bearing capacity. To determine if soil conditions and cribbing are adequate, the operator must calculate the pressure placed on the soil by each of the pump truck's outriggers. Outriggers and cribbing also must be set on level ground. If the soil is sloped, dig a ledge for the cribbing to sit on. Never bridge a hole with cribbing, and never set cribbing on uneven or hilly soil.