Recommended Operating Practices

Safety_First_0_0

• All users must be trained and knowledgeable in sling selection, use and inspection of slings, cautions to personnel, environmental factors and rigging practices.

• Know the weight of your load.

• Use a sling with characteristics meant for the type of load, hitch and environment with which you are working.

• Never ride a sling or load.

• Never load a sling in excess of its rated capacity. Always consider working load limit reduction factors such as angle and/or tension.

• Never tie or knot a sling, or use a sling with a knot in it.

• Protect the sling from being cut by corners, edges and abrasive surfaces by using wear pads or sleeves of sufficient strength to prevent damage to sling.

• Make sure the sling is securely attached to the lifting point.

• Do not stand near or under a suspended load and keep it clear of other obstructions.

• Do not drag a sling across the floor, over abrasive surfaces, or from under a load.

• Don’t shock (jerk) load when lifting.

• Take damaged slings out of service immediately.

• Liftex® always recommends synthetic slings be protected by appropriate wear protection:
– Sewn-On Wear Pads
– Sliding Sleeves
– Quick Sleeves
– Edge Wrap
– Eye Buffers

• Protection can come in the following materials:
– Buffer Web
– Heavy Duty Sling Web
– Leather
– Super Pad Felt
– PVC Belting

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Additional Resouces



Factors Affecting Synthetic Sling Performance

Cutting:

The most common cause for a sling being taken out of service. All synthetic slings are subject to cutting when lifting items with edges. Edges that come in contact with the sling should be padded with material of sufficient strength to prevent damage to the sling. Wear pads give extra protection to the sling where the most wear occurs. Please refer to our page on wear pads and sleeves for all of your options. Regardless of location or type of cut – anytime a sling is cut in any way, shape or form – it must be removed from service.

Ultraviolet Exposure:

Environments in which synthetic webbing slings are continuously exposed to ultraviolet light can affect the strength of synthetic webbing slings in varying degrees from little to total degradation.

Suggested procedures to minimize the effects of ultraviolet light and sun light:
– Store slings in a cool, dry and dark place when not being used for prolonged periods of time.
– Inspect slings weekly or even more frequently depending on sling use.

Visual indications of ultraviolet degradation are:
– Bleaching out of sling color
– Increased stiffness of sling material
– Surface abrasion in areas not normally in contact with the load
– Slings used in environments where they are subject to continuous exposure to ultraviolet light should be proof tested to two times rated capacity annually, or more frequently depending on severity of exposure.

Chemically Active Environments:

Chemically active environments can affect the strength of slings in varying degrees, ranging from little to total degradation. Before ordering slings that are to be used in a chemically active environment, give us a call. We would be pleased to recommend the right sling for your application.

Acids:

Nylon is subject to degradation in acids ranging from little to total degradation. Polyester is resistant to many acids, but is subject to degradation ranging from little to moderate in some acids.

Each application must be evaluated, taking into consideration the following:

Type of acid, alkali or other chemical
Exposure conditions
Concentration
Temperature

Alkalis:

Nylon is resistant to many alkalis, but is subject to degradation ranging from little to moderate in some alkalis. Polyester is subject to degradation in alkalis, ranging from little to total degradation.

Improper Loading:

Overloading, imbalanced loading, shock loading, failure to consider hitch, angle and tension effect on rated capacity reduction – all of these issues can reduce the functionality, safety and integrity of the sling. Always adhere to rated capacities; always take into consideration hitch, angle and tension in calculating working load limit; build and rig loads such that they are properly balanced and always avoid shock-loading.

Sling Length:

The selected sling must be of sufficient length to accommodate the load when factoring in the sling to load angle. Failure to consider sling length in conjunction with sling to load angle can result in an overloaded sling.

Proper Care and Storage:

Slings should be stored in a clean, dry environment. Slings should be hung from a rack. For maximum ultraviolet protection – store slings in a dark area.

Foreign matter:

Dirt, grease, grit, metal chips – any foreign matter can damage the sling. Make all efforts to keep slings clean and free of foreign materials.

Holes, tears, abrasion, etc.:

Any violation of the integrity of the sling construction can and will reduce the performance of the sling. Always use appropriate padding and wear protectors; avoid dragging slings across floors; avoid pulling slings from under loads.

Temperature:

Typical synthetic slings (flat/web slings and roundslings) are not specified for use in temperatures exceeding 180°F (82°C) or below -40°F (-40°C). For information on lifting solutions in environments beyond these parameters, contact Liftex®.

Type of Hitch

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Choker_Hitch_P1

Choker Hitch:

The sling is passed around the load and through one eye. The remaining eye is engaged to the hook. Note that the angle of choke can result in a reduction to the rated capacity for that operation. See chart titled “Choker Hitch Adjustment.”

Basket_Hitch_P1

Basket Hitch:

The sling surrounds the load while each eye is engaged to the hook (or hooks) above. Note that a basket hitch can be used in either a single or double hook configuration. Note that the sling-to-load angle can result in a reduction to the rated capacity for that operation. See chart titled “Sling Angle – Reduction Factor”. Additionally, the sling-to-load angle can result in increased tension. This increased tension should be factored into sling selection. See chart titled “Sling Angle – Tension Factor.”

Vertical_Hitch_P1

Vertical Hitch:

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

Bridle_Hitch_P1

Bridle Hitch:

Two or more legs coming from one collection point.

Sling to Load Angle

SlingToLoad_H1_1

When selecting a sling to carry a given load, it is important to consider the angle at which the sling will be used. As an example, one sling in a basket hitch or two slings attached to one crane hook are different applications involving different sling angles. The degree of the angle will determine how much capacity will be reduced. To determine if a particular sling will have the capacity required, take the angle between the sling leg and the horizontal, then multiply the sling’s rating by the factor provided in the accompanying table.


SlingAngleTensionChart_H1

Sling Angle Reduction Factor & Tension Factor

For Basket & Bridle Hitches

Method 1- Determine Reduction to Rated Capacity

1) Calculate the Sling to Load Angle (see page 16 – Sling To Load Angle).
2) Determine the associated reduction factor (see chart).
3) Multiply the rated capacity for the basket hitch as indicated on the sling tag by the reduction factor.
4) The result is the safe capacity designation for that sling in that rigging configuration.

Method 2- Determine Increased Tension/Effective Weight of the Load

1) Calculate the Sling to Load Angle (see page 16 – Sling To Load Angle).
2) Determine the associated tension factor (see chart).
3) Multiply the load weight by the tension factor.
4) The result is the “Effective Weight” of the load in that rigging configuration- be sure to select a sling
with adequate capacity. (A longer sling will increase the Sling to Load angle, thereby reducing the
tension factor/effective weight of the load.)

For Choker Hitches

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Angle_Tension_Charts_M1_2

When a load is rigged using a choker hitch- if the choke angle is less than 120°, then the rated capacity of the sling must be reduced.

1) Calculate the angle of choke (see illustration).
2) Determine the associated reduction factor (see chart).
3) Multiply the rated capacity for the choker hitch as indicated on the sling tag by the reduction factor.
4) The result is the safe capacity rating for that sling in the rigging configuration.

SLING STRENGTH RELATIVE TO CONNECTIVE HARDWARE: As stated by WSTDA, sling strength is affected by the size of the connection hardware. Refer to WSTDA standards for information pertaining to appropriate connection hardware sizes.