Which signal indicates boom down?

The signal indicating boom down involves an arm position that is horizontal with the thumb pointing down. This specific gesture is universally recognized in signaling for cranes and lifting equipment—where the arm's position and thumb orientation denote specific actions to be taken by the operator.

When the arm is horizontal and the thumb is pointed down, it explicitly communicates to the operator that the boom should lower. This clear visual cue helps ensure safety on the job site by providing concise and unambiguous instructions for movements that require precise coordination and responsiveness.

Other signals may imply different actions or movements, but the combination of an outstretched horizontal arm and a downward thumb specifically denotes that the boom should be moved lower. Understanding these hand signals is essential for effective team communication and safety in welding and crane operation environments.