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Basic Rigging


Rigging and CranesThis Rigging and Cranes Presentation will review general rigging principles, general cranes types and components , crane safety and hand signals to direct crane operation. Click on the subject below to hyperlink to a specfic presentation.

Basic Industrial Rigging & Cranes

Industrial Rigging Cranes Crane Safety Crane Hand Signals

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Basic Rigging


Objectives Basic Industrial Rigging & Cranes

Define Rigging Principles Define Loads Define Sling Angles Define Sling Safe Working Load Define Hitch types Define Rigging Equipment Define Block and Tackle Define Levers and Mechanical Advantage

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Basic Industrial Rigging & Cranes

Hoisting and Rigging refers to the lifting and moving of loads using mechanical devices Objectives of rigging training programs: Protect personnel from injury Protect equipment from damage Protect property from damage Protect the environment from harm

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Basic Rigging Principles

Basic Industrial Rigging & Cranes

Rigging is the process of moving heavy loads with ropes, chains, hoists and other special tools. The equipment used for lifting and moving loads is also called rigging. Safety must be the foremost concern: any task involving airborne loads can be extremely dangerous if not handled carefully and properly.

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DefinitionsStatic load: the load resulting from a constant applied force or load. Working load limit: the maximum mass or force which the product is authorized to support in general service when pull is applied in-line. Interchangeable with the following terms: Working load limit (WLL). Rated working load (RWL). Resultant working load (RWL).

Basic Industrial Rigging & Cranes

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DefinitionsProof load: the average force applied in the performance of a test. Proof test: A test applied to determine manufacturing defects. Ultimate load: the average load of force at which the product fails or no longer supports the load. Shock load: A force that results from rapid application of a force or rapid movement of a static load. Design (safety) factor: an industry term denoting a products theoretical reserve capability. Usually expressed as a ratio (example 5 to 1).

Basic Industrial Rigging & Cranes

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Finding the WeightBasic Industrial Rigging & Cranes

The weight of the load is the first piece of information required when planning a rigging job. The first place to look for the weight is on the load itself. The weight could be found in the equipment manual or operators guide. The weight could be estimated.

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Estimating WeightThere are two ways to estimate load weight 1. Estimate the weight by comparing it to the known weight of a similar piece. 2. Calculate the volume of the load and multiply that figure by the density of the material. Example: steel weighs 490 pounds per cubic foot. 10 cubic feet of steel = 490 x 10 = 4,900 pounds.

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Basic Industrial Rigging & Cranes

Basic Rigging PrinciplesRigging safety involves three elements: Planning the job. Inspecting the equipment. Using the equipment properly. Planning a rigging job consists of four steps. 1. Finding the weight of the load. 2. Determining the balance of the load. 3. Checking the clearances for moving the load. 4. Selecting the rigging equipment to be used.

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Basic Industrial Rigging & Cranes

Determining the BalanceEvery load must be balanced if it is to be lifted safely, therefore unbalanced loads will tilt or swing when they are lifted. Some loads are much more easily balanced than others, which makes a regularly shaped load easier to lift from a point balanced above its center. Loads with irregular shapes may be more difficult to balance and will take greater care when rigging is to be done.

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Basic Industrial Rigging & Cranes

Determining the BalanceEvery object has a point at which it will balance perfectly. This point is call the objects center of gravity. When a load is lifted from a point directly above its center of gravity, it will remain stable. One way to find a loads center of gravity is to make a model of the load .

Basic Industrial Rigging & Cranes

To find the model center of gravity, it is lifted from several points. While the model is suspended from each lift point, a line is drawn straight down from the lift point being used. Since the center of gravity always shifts so that it hangs directly beneath the lift point, all the lines will intersect at the center of gravity.

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Checking Clearances and RouteChecking clearances is the third step in planning a rigging job. Before a load is moved, the size of the load must be compared to the size of the corridors and the tight spots along the way to make sure that the load will fit. The best way to avoid mistakes is to measure the load and path to make sure there is sufficient clearance for the load and equipment being used to transport the load.

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Basic Industrial Rigging & Cranes

Checking Clearances and RouteWhen planning the route over which a load will travel, several other considerations are as important as clearances. The load should be kept as close to the floor as possible. Loads should not be lifted over other equipment unless no other route is possible. People must be kept out of the way. Loads should never be lifted above a person.

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Basic Industrial Rigging & Cranes

Selection of EquipmentOnce a loads weight, balance and the necessary clearances have been determined, enough information exists to select the equipment for the job.Basic Industrial Rigging & Cranes

Rigging equipment, in general can be grouped into four categories:

Hoists and Cranes provide lift. Slings short lengths of wire rope, chains or synthetic fibers used to attach a load to a hoist or crane. Connectors hooks, eyebolts, and shackles used to link different pieces of rigging together. Adjustors load levelers and turnbuckles used to balance loads.

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Three types of fiber-line and wire-rope slings are commonly used for lifting a load are

Basic Industrial Rigging & Cranes

the endless sling single- leg sling bridle slings

The ENDLESS SLING, can be made by splicing together the ends of a piece of fiber line or wire rope to form an endless loop. The endless sling is easy to handle and is frequently used as a choker hitch. A SINGLE-LEG SLING, commonly referred to as a STRAP, can be constructed by forming a spliced eye in each end of a piece of fiber line or wire rope. Sometimes the ends of a piece of wire rope are spliced into eyes around thimbles, and one eye is fastened to a hook with a shackle. With this arrangement, the shackle and hook are removable. A single-leg sling also may be used as a choker hitch. Bridle slings are usually made from single-leg slings.

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Sling AngleWhen slings are to be used the least amount of tension is exerted when using vertical slings. When shorter slings are being used, their angle moves farther away from vertical, creating steeper angles and therefore more tension is produced. In extreme cases, the greater the angle, the greater the tension, causing overloading of the slings. The prevent overloading slings, their angle must be no greater than 60 degrees from the vertical.

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Basic Industrial Rigging & Cranes

Sling Angle Load ExamplesExamples of how sling angles affect the loading on the legs of a sling. Sling capacity decreases as the sling angle decreases

Basic Industrial Rigging & Cranes

500 lbs

1000 lbs 1000 lbsbs 7l 57

57 7l bs

lb s

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500 lbs90

1000 lbss lb30


70 745

lb s

0 00 1

10 00


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1000 lbs

1000 lbs

1000 lbs

1000 lbs

Calculating Sling Load

In order to calculate the load on a sling two items are needed:

Basic Industrial Rigging & Cranes

Sling angle Load to be lifted


1000 lbs The following table gives the load angle calculation factor for some common angles. Use the formula Sling Load = Load x Load AngleLoad in each sling = Factor 500 x Load AngleSling Angle Degrees 90 60 50 45 30 Load Angle Factor = L/H 1.000 1.155 1.305 1.414 2.000

Factor L H A 1000 lbs

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Load on each leg of sling. Sling = Vertical Load x Load Angle Factor

Load in each sling = L/H x 500

Sling Angle What it means basically

Basic Industrial Rigging & Cranes

To gain a perspective assume that a 3/8 inch wire rope is rated for 2000 lbs in a vertical lift. In a four point lift the maximum load can then be 8000 lbs (4 tons). If the sling angle is changed to 60 degrees then the max load seen by each sling is 2310 pound and the total load seen by the slings is a total of 9240 pounds. This exceeds the lifting capacity of the wire rope. The solution would be to use a larger wire rope or reduce the load size. 2000 lbs60

2310 lbs

8000 lbs

8000 lbs

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Ropes and ChainsRopes and chains are perhaps the most common of all rigging tools. They are used on hoists and cranes and as slings to attach a load to a lifting device Rope is the oldest of all tools still used in rigging. In the past, all ropes were made of vegetable fibers twisted together to make a sturdy line for lifting and hauling. Although natural fiber ropes have some use in rigging today, ropes made of synthetic fib

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