NCCCO Signalperson key terms

A hand signal given with the arm extended horizontally to one side, palm down, moving the arm back and forth. It tells the operator to stop all crane motion and is used for routine, non-emergency stopping.

Both arms extended horizontally to one side, palms down, moved back and forth together. It tells the operator to stop all movement at once because of imminent danger to people or property.

Forearm held vertical with the forefinger pointing up, hand moved in small horizontal circles. It tells the operator to raise the load or hook; the circling motion does not mean swing.

Arm extended downward with the forefinger pointing down, hand moved in small horizontal circles. It directs the operator to lower the load or hook under control.

One hand gives the normal motion signal while the other hand is held motionless in front of it. This tells the operator to perform that same motion at reduced speed.

Hands clasped together in front of the body. It tells the operator to lock or hold all crane functions in their current position, often while the crew regroups or repositions.

Arm extended outward with the finger pointing in the direction the boom should rotate. The operator swings the upper works that way while keeping the load under control.

Arm extended outward with fingers closed and the thumb pointing up. It tells the operator to raise the boom, which increases the boom angle.

Arm extended outward with fingers closed and the thumb pointing down. It tells the operator to lower the boom, which decreases the boom angle.

Both fists held in front of the body with the thumbs pointing outward, away from each other. It tells the operator to telescope the boom out, making it longer.

Both fists held in front of the body with the thumbs pointing toward each other. It tells the operator to telescope the boom in, making it shorter.

Arm extended forward with the hand open and slightly raised, making a pushing motion in the direction of travel. It tells the operator to move the crane that way.

Arm extended outward with the thumb up or down while the fingers flex in and out. Thumb up means raise the boom and lower the load; thumb down means lower the boom and raise the load.

Voice communication by radio between the signalperson and the operator, used when hand signals cannot be seen or when the lift needs spoken direction. Both parties must hear and understand each other clearly.

A method in which the signalperson gives a direction, the operator repeats it back, and the signalperson confirms it before the move starts. It prevents misheard commands on the radio.

The specific channel or frequency agreed on before the lift begins. Everyone involved stays on it and unrelated traffic is kept off so commands are not missed.

A short test before the lift in which the signalperson and operator confirm they can hear and understand each other clearly. If there is any problem, the lift should not start.

A spoken command telling everyone to stop crane motion at once. Any person who sees danger may give it, and the operator must respond immediately no matter who said it.

A request to repeat a voice command that was not heard clearly, or the operator's habit of repeating a command before acting. It is used instead of guessing at an unclear direction.

The turning effect created by the load's weight multiplied by its distance from the crane's tipping axis. A higher load moment means the crane is closer to its capacity or tipping limit.

The point where a load's weight is balanced in every direction. The hook must hang directly over it so the load rides level and does not tilt or swing unexpectedly.

The horizontal distance from the crane's rotation center to the center of the hoist line. As the radius increases, the rated capacity usually decreases.

The angle between the boom and level ground. It sets the working radius and the capacity, so the signalperson watches it change as the boom is raised or lowered.

The greatest load a crane may lift at a given radius, boom length, and configuration, as listed in the manufacturer's load chart. It already accounts for required deductions.

The downward bending of a loaded boom, which lowers the load slightly and changes the radius. The signalperson allows for it when judging where the load will land.

Pulling or pushing the load or boom sideways, a force a crane is not built to resist. It can buckle the boom, so the signalperson keeps the load directly under the boom tip.

Pulling the load block up against the boom tip until the blocks touch. It can snap the hoist rope and drop the load, which is why anti-two-block devices are required.

A safety device that senses when the load block nears the boom tip and stops the hoist before the blocks collide. It also warns the operator that the limit has been reached.

The outward pull felt by a load as the crane swings, caused by centrifugal force. Fast starts and stops swing the load wide and can tip the crane or strike nearby objects.

The force the crane's outriggers or tracks put on the soil beneath them. Soft or unlevel ground lets a crane shift, so mats or cribbing are used to spread the load.

A rope tied to the load and handled by a worker on the ground to keep the load from spinning or swinging while it is lifted.

A sudden jerk on the crane caused by snatching a load off the ground or stopping it abruptly. It creates forces far greater than the load's weight and can overload the crane.

The exposed surface of a load that catches the wind. Large flat loads catch more wind and can swing or tip, so lifts may be limited by wind speed.

A person the employer has trained and evaluated as able to give the required hand and voice signals and to understand crane operation, as required by 29 CFR 1926.1428.

The one person chosen to direct the operator during a lift. Only that person's signals are followed, except that anyone may give a stop signal.

The rule that any worker who sees a hazard may give a stop or emergency stop signal, and the operator must obey it, even if that worker is not the designated signalperson.

The record the employer keeps showing the signalperson was evaluated and is qualified, including who did the evaluation and when. It must be available when requested.

A person who tests a signalperson's knowledge and skills and confirms the person meets the requirements. The evaluator must be competent and may come from a third-party organization.

When hand or radio contact between the signalperson and the operator breaks down. Crane operations must stop until communication is restored, because the operator cannot see the load path.