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Archive for March, 2009

Crane Hand Signals – Directing Crane Movements

How do I tell the guy what I want done with my load which is hanging from his crane?

When you rent a crane or boom truck you want the most for your money. You need to be able to quickly and efficiently communicate to the operator exactly what it is you are trying to do. Fortunately there is a universal language for directing crane movements… The Standard Hand Signals. These same signals are officially used all over the world… though right here in the USA we see some pretty imaginative variations from time to time!

Crane lifting signals

Standard Crane Hand Signals

Don’t be afraid of the long list of signals, you can very effectively direct your crane operator’s movements with just four, and those four are simple and intuitive. What will take more attention and practice is the perception you want to have as signalman to keep the job going smoothly:

  • The signalman becomes the eyes of the crane operator. Often, the operator can’t see the load, it is out over a flat roof or the other side of a wall, etc. Even when the load is right in front of him, he can’t see through it.

“I’ve hoisted dozens of glass panels and bundles into place and I can’t even see clearly through most of them- maybe it’s me, but I depend on my signal man to let me know which direction to move the load. He is free to position himself where he can see the far corners of the load and any obstructions in the path of movement. He can also see the most diminutive target marks in the floor and accurately guide me to set the load exactly on them. Furthermore, the signalman can more directly communicate with, and help keep up with, people seemingly determined to place their hands and bodies in the path of or even under the load!” -clyde

  • The signalman has to be aware of the path the load will follow for each signal he chooses. Crane signals are designed to tell the operator what function of the crane to activate and in what direction. A crane hand signal causes a load to move with respect to a crane, not a building or road.

“Moving a load along a road or between two walls running alongside the crane, for instance, will require a combination of signals because the operator will have to carefully coordinate SWING, BOOM luffing, and HOIST functions to follow a straight path. The crane SWINGS the load in a horizontal arc around the crane. Likewise, BOOM UP will cause the load to move in a vertical arc up and toward the crane. Converting these arcs into straight paths requires skill and familiarity with the particular nuances of each crane and configuration. Unless there are obstructions to be maneuvered around, your job will go more efficiently if the signalman recognizes the natural arcs of crane motion and moves the load in those arcs.” -ralph

  • The crane moves when and where the signalman directs. This also means: THE CRANE IS NOT TO MOVE WHEN THERE IS NO SIGNAL VISIBLE! Your job site will be more efficient and safer if your signalman continuously signals as long as he desires motion of the crane. In other words, if the crane operator ceases to see a signal, he should smoothly stop the crane and let go the controls.

“Every day we see people show up at the edge of a roof, vigorously signal LOWER LOAD, then disappear from view! We want to do what you ask, we really do. But more importantly, we know that it is extremely dangerous to lower a heavy load with NO WAY to get an emergency stop signal if someone sticks their hand under it to feel for alignment or a previously unnoticed gas line or electrical wire is suddenly seen!” -david

  • Be sure your signals are visible to the operator. The perception is that if you can make eye contact with the crane operator, he can automatically see your signals. Wrong… and it is a false perception that a good signalman has to work hard to change.

“We see this happen (or can’t see it) several times a day, sometimes several times on one job! There are lots of columns, people, work platforms, vehicles, door jambs, guard rails, bracing, etc. that you can put your signal hand behind while you look at the crane operator’s cab glass- keeping your face and eyes carefully in the only clear spot available!

TRY THIS: Put your signal hand in the clear spot, turn around and look at the load and watch where it’s going as you signal the crane!” -butch

Another clear visibility issue a signalman needs to be cognizant of:

Watch out for the sun (or work lights at night). If you see yourshadow ANYWHERE NEAR the crane cab, the operator may not be able to see you and/or may be unnecessarily in extreme discomfort trying to follow your wishes. Work lights need to be aimed to illuminate the signalman, the load, the travel path of the load, and the crane boom where there are known obstructions or hazards. The signalman, nor anyone else, needs to see the crane operator or the outside of the crane cab.

OK, I get it, it’s all about and around the crane. But why coded signals, can’t I just tell the operator what I want?

Well…yes, and please do…but also…

Along with the huge advantages inherent in any universally understood form of communication, using hand signals to direct your crane optimizes your job in the following ways:

  • Clarity. The limited ‘vocabulary’ of the Standard Hand Signals tends to minimize ambiguity. The ‘speaker’ may only use signals, or a combination of signals, directly associated with the crane controls.
  • Speed. Visual signals travel at, well, the speed of light. More importantly, with practice, the human hand can form a complex signal faster than the human tongue can get out even a single syllable.
  • Distance. Cranes are generally used when a greater reach is required or loads must be handled over obstacles. Verbal directions quickly become easy to misconstrue as the distance between speaker and listener increases.
  • Noise. Relying on HAND SIGNALS means the high noise levels at most industrial and construction sites don’t interfere with critical communication.

With a good signalman’s perception of the crane operating parameters, here’s the four signals that’ll put your load on target quick and easy:

  • STOP. The one of the four nearly everybody already knows instinctively… STOP! You simply place your open hand horizontally to the side about waist high, palm down. Move your palm sideways in a back and forth sweeping motion. Use both arms for an emergency stop. Don’t do emergency stop every time the load goes a little past where you wanted it. The load is moving, so the signalman wants to be thinking ahead and signaling in plenty of time for a smooth, controlled slow down to stop over the target… The way you want your load handled!crane lift signal

“I prefer my signalman to rarely or never use the STOP signal. To be efficient and do it all day, TRY THIS: As your load approaches within a few feet of the destination use the SLOWLY signal (place your other hand near the active signaling hand, palm open and toward the active signal). Then, as the load approaches within inches of the target, deliberately drop your arms to your sides, ceasing crane signals. Or deliberately change to a hoist down slowly signal if you are ready to place the load. The point is, since the operator is going to smoothly stop the load when he no longer sees a signal, to just stop signaling is a highly efficient, clear, and safe way to place a load!” -zane

Two of the other signals are so intuitive, you may already be using them to direct your cranes… SWING and HOIST. Both of these signals are basically pointing with your index finger:

  • crane lift signal lower loadHOIST- operate the load line winch.

Be sure your entire forearm is near vertical and slightly rotate your finger tip(s) as though drawing a circle with your hand. This signal is reversed according to whether you want the load to be raised or lowered- your finger(s) point up for Hoist the Load and down for Lower the Load.

Though not an official embellishment, circling faster or slower is prevalent to communicate your wish to speed up or slow down the hoisting speed. If you require very slow hoisting speed, the Standard Hand Signal is to place your other hand flat (horizontal) a few inches from, and palm facing, your circling fingers.

  • SWING- move the load in an arc around the crane.

SWING is even simpler to do than hoist… JUST POINT! Really… use your entire arm when possible and point in either direction the crane can rotate about it’s center of rotation. Try to have your back somewhat to the operator’s cab and point somewhat perpendicularly into (or away from) the side of the boom. Usually it is pretty clear which way you want the boom to swing, but if you do this enough you will find that there are predicaments on job sites where the signalman is far removed from the suspended load and care must be taken to indicate a clear direction of rotation. For example, pointing at, or anywhere in the vicinity of, the operator’s cab does not tell him a whole lot, even if the boom is there too! Remember…The crane SWINGS the load in a level arc around the crane. The arc being part of a circle, the center of the circle being the center of rotation of the crane.

  • crane lift inBOOM luffing- make the load go away from or toward the crane.

The last signal, and the most misunderstood (misused anyway) is BOOM luffing. Luffing is changing the vertical angle of the boom with respect to level grade. It is not the same as extending or telescoping the boom (which is to change the length of the boom)…. and it is not the same as operating the load line hoist drum (which is done to HOIST or crane lifting outLOWER the load, not the boom). A signalman will use the BOOM UP or BOOM DOWN signal when he wants the load moved toward the crane or away from the crane. You will find it more useful on the job if you use the combination signals BOOM UP & LOWER LOAD or BOOM DOWN & HOIST LOAD. These combination signals let the operator know to keep the load at a constant elevation as he moves it either toward the crane or away from the crane.

crane boom liftBOOM UP. Also referred to as RAISE BOOM. If you want the load moved closer to the crane then you stick your arm out to the side, make a fist and point your thumb up, signaling BOOM UP. If it is important that the load not go up as it moves back toward the crane- use the BOOM UP & LOWER LOAD signal: Arm extended to side, thumb up, fist constantly opening and closing- the BOOM UP signal with a little motion. The title BOOM UP & HOLD the LOAD is more accurate, however, both titles refer to the same crane functions… the crane operator must boom up while he coordinates running the hoist drum down at a speed equivalent to the vertical velocity vector of the arc of travel of the boom tip. Fortunately, it’s usually a lot easier to do it than to explain it. The load should stay at approximately the same level as it slowly moves straight toward the crane.

crane boom lift downBOOM DOWN. (LOWER BOOM) To move the load away from the crane, extend your arm at shoulder level, make a fist and point your thumb down. To be sure the load doesn’t also lower (since you are instructing the boom to be lowered), fully open and close your fist. The BOOM DOWN & HOIST LOAD signal let’s the operator know to hoist up on the load line drum in coordination with the lowering of the boom tip… keeping your load at a level height as it moves away from the crane. ALWAYS KEEP THE LOAD AS LOW AS PRACTICAL during BOOM DOWN & HOIST LOAD. If the crane were on weaker ground than supposed or any human error were made in terms of load weight, outrigger configuration, etc., everybody would most likely find out while moving the load further and further from the crane. Why be foolish? Keeping the load low doesn’t cost time or effort, but if you do enough lifting you will someday be thankful for good habits developed now!

Another very useful embellishment I see a lot is to open and close your fist faster when you want more hoist speed and slower when you want less. Unofficial, of course, but handy to keep that load just the right height when the operator can’t see it.

PS: Don’t worry about your signalman too much just yet. At SS CRANE & RIGGING our operators are there to get your lift done quickly and safely. We always have and always will communicate any way that works… cell phones, radios, your particular form of hand signal, or just tell us where you want the load and when to start lifting it! Call us at 678-848-6386 for the best performing combination of crane and operator at a NO SURPRISE price!

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