Operating Principles, Boom Movements and Safe Positioning
Smooth, controlled operation
Operate the boom smoothly and predictably. Use slow, deliberate movements; avoid sudden starts, stops and reversals that can induce dynamic loads and whip the end hose. Keep the boom within its rated envelope and never exceed the load chart for the boom configuration. Coordinate with the pump operator and the placing crew - the end hose must be guided by a person using a guide rope or handle, never by hand directly under load.
Positioning
Position the boom so the end hose reaches the pour area without over-extending or over-slewing. Keep the boom clear of structures, scaffolding, and powerlines. Maintain the required exclusion zone from overhead lines - if the zone cannot be maintained, isolate or de-energise the line. Never allow workers to stand under the boom or the concrete stream. Watch for wind: the boom acts as a sail and wind can cause loss of control, so stop when wind exceeds the manufacturer's limit.
Traps in exam questions
Questions often test whether the operator may leave the controls while the boom is in motion - they must not. Another trap is using the boom to drag or pull the pipeline or to free a blockage by force. Also, slewing over people or traffic is a common exam hazard. Remember that the end hose must not be used to support a person or as an anchor.
Rule of thumb
If you cannot see the end of the boom or your signals, stop. Line of sight or reliable communication is a precondition for movement.