Basicsof

Rigging

Types of Rigging• Chain-well suited for high

temperature, rugged loads, and repetitive lifts under harsh conditions. Chain slings can be inspected, repaired, tested, and recertified. • Synthetic-good for protecting

finished surfaces.

• Wire Rope-most common, lowest cost per ton for lifting capacity• Mesh-excellent for lifting objects

that are hot or have sharp edges. Mesh slings enhance load balancing due to wide load bearing surfaces.

What to look for when inspecting synthetic slings• Missing or illegible sling identifications• Cuts, gouges, areas of extensive fiber breakage

along the length and abraded areas on the rope• Uniform fiber breakage along the major part of

the length of the rope in the sling such that the entire rope appears covered with fuzz or whiskers

• Fiber breakage or melted fiber inside the sling that appears along the length at the same relative position and involves damage estimated at 10 percent of the fiber in the strand at that point

• Discoloration and brittle or stiff areas on any part of the sling,

• Foreign matter that has permeated the rope and attracts and holds grit

• Kinks, distortion, or other damage in the rope structure

• Melted or charred areas that affect more than 10 percent of the diameter of the rope or affect several adjacent strands along the length to more than 10 percent of their individual diameters

• Poor condition of thimbles or other fittings manifested by corrosion, cracks, distortion, or localized wear

• Other conditions that cause doubt as to continued use of the sling

Synthetic slings

What to look for when inspecting wire rope slings• Broken wires• Severe localized abrasion or

scraping • Kinking, crushing, bird caging, or

any other damage to the rope structure• Evidence of heat damage• Crushed, deformed, or worn end

attachments

• Severe corrosion of the rope, end attachments or fittings• Missing or illegible sling

identifications• Other conditions that cause

doubt as to continual safe use of the sling

Wire rope

Kinks

BirdcagingCorrosion

Severe Abrasion

What to look for when inspecting chain slings• Wear• Defective welds• Nicks, cracks, breaks, gouges,

stretch, bends, discoloration due to excessive heat• Excessive pitting or corrosion

• Throat opening of hooks• Missing or illegible chain

identifications• Other conditions that cause

doubt as to continued safe use of the chain

Chain slings

Bent links Corroded links

Worn link ends

Bent, twisted,Stretched hooks

What to look for when inspecting mesh slings• Broken wires in any part of the mesh• Broken weld or broken brazed joint along the

sling edge• Reduction in wire diameter of 25 percent or

more due to abrasion or 15 percent or more due to corrosion

• Lack of flexibility due to distortion of the mesh• Distortion of the choker fitting so that the

depth of the slot is increased by more than 10 percent

• Distortion of either end fitting so that the width of the eye opening is decreased by more than 10 percent

• A 15 percent or more reduction of the original cross-sectional area of any point around the hook opening of the end fitting

• Visible distortion of either end fitting out of its plane

• Cracked end fitting• Sling in which the spirals are locked or

without free articulation• Fittings that are pitted, corroded, cracked,

bent, twisted, gouged, or broken• Missing or illegible sling identifications• Other conditions that cause doubt as to

continued use of the sling

Mesh slingsBroken joint

Corrosiondamage

Distorted endfitting

AbrasionOverload/

Uneven load

How to determine sling load from angle changes• From the previous slide, you can see that the rigging angle greatly

affects how much tension is applied to the sling. The ideal angle for the sling is 90o.

1) Determine sling angle and capacity.2) From the chart on the previous slide,

determine the angle factor. For example, for a #5000 capacity strap at a 65o , you would multiply 5000 by .906. The answer would tell you that the strap is reduced to a capacity of #4530

1) Determine sling angle.2) Determine load weight.3) From the chart on the previous slide,

determine the angle factor. For example, for a #5000 with rigging at a 65o , you would multiply 5000 by 1.104.

4) The answer would tell you that the tension on your rigging is increased to #5520.

Method 1 Method 2

More on sling tension

• When determining sling angles and tension, and load weight, remember that you can divide the load by the number of slings, as long as every sling is the same length and at the same angle.

Vertical Hitch

• One eye is engaged directly to the load while the other eye is engaged to the hook.

Bridle Hitch

• Two or more legs coming from one collection point.

Basket Hitch

• The sling surrounds the load while each eye is engaged to the hook (or hooks) above.

Choker Hitch

• The sling is passed around the load and through one eye. The remaining eye is engaged to the hook

How angles affect the loadThe angle at which a sling is used significantly effects its capacity. Use the longest reach possible for completing the lift; this will provide the largest angle possible for minimum stress on the sling.

Angles affecting chokers

Angles affecting basket and bridle hitches

Hazard Recognition

Check for overhead obstructions and/or electrical linesOne designated signalpersonInspect rigging prior to use

Verify rigging will support loadConstruct danger tape barricade around lift area or swing radius

Ensure crane/forklift/hoist is inspected prior to use

Basic Signals• Cable up/down• Boom up/down• Telescope in/out• Swing left/right• Cable up/down and hold load• Boom up/down and hold load• Move slowly• Stop everything

Reference• Liftex • http://www.liftex.com/index.html

?page_id=163

• OSHA• www.osha.gov