Safe Slinging Practices

Types of SlingsTypes of Slings

1) Wire Rope Slings

2) Chain Slings

3) Synthetic Web Slings

Ropes, chains, and slingsRopes, chains, and slings

• Primary hazard is structural failure due to:– Overloading (“the weakest link”)– Deterioration and/or wear– Environmental exposure– Improper rigging– Abuse

Natural fibre ropesNatural fibre ropes

IS: 1084—1969 Manila Rope

IS: 1321—1970 Sisal Rope

MANILA — Black Yarn

Grade-I SPECIAL QUALITY ALL THE THREE STRANDS

Grade-II STANDARD QUALITY ALL THE TWO STRANDS

Grand-III MERCHANT QUALITY ONE STRAND

SISAL Red or Green YARN in one strand

SWL of Fibre ropesSWL of Fibre ropes

Value Condition SWL

ONE Rope of which original Fibre strength is not reduced

Same as per new Rope

TWO Rope which has been used and shows slight external wear and chafe

80% of the New80% of the New

THREE Rope which has fair amount of usage,clear indication of internal and external wear, loosening of strands

NOT TO BE USED NOT TO BE USED FOR HOISTINGFOR HOISTING

Fibre ropesFibre ropes

Once a Fibre Rope is condemned it should be cut Once a Fibre Rope is condemned it should be cut with a knife so as to ensure that it should not be with a knife so as to ensure that it should not be used again.used again.

Causes of Deterioration

Fibre ropesFibre ropes

ROUGH USE Rubbing against sharp edges

Damaged groves of sheaves

Dragging from under the load

HARMFUL CONTACT With water, oil, chemicals and heat

BAD STORAGE Heap on wet floor, poorly ventilated godown

Internal wear by Repeated Flexing

Synthetic Fibre ropesSynthetic Fibre ropes

IS: 4572– 1968 Polyamide (Nylon Filament Rope)

IS: 5175– 1969 Poly Propylene Rope

IS: 8674– 1978 Polyethylene Rope

Advantages

• Light in Weight

• Higher Strength

• Increased Resistance to Repeated Bending, Flexing and Abrasion

• Resistance to water and

• Choice of Selection

Wire Rope and Wire Rope Wire Rope and Wire Rope SlingsSlings

Components of Wire Rope

Left Lay

Right Lay

Crushing

Because of loose winding on drum, rope was pulled in between underlying wraps and crushed out of shape.

Birdcaging

The sudden release of a load cause birdcaging.Here individual strands open away from each other, displacing the core.

Locking of strands

Premature breakage of wires resulted from "locking" of strands, which was caused by insufficient lubrication.

Abrasion

Neglect of periodical inspection left this rope in service too long, resulting in considerable abrasion.

Kinking

Kink or "dog leg“ was caused by improper handling and/or installation. A kink causes excessive localized or spot abrasion.

Reverse bending

Running this rope over one sheave and under another caused fatigue breaks in wires.

Pitting

Too much exposure combined with surface wear and loss of lubrication caused corrosion and pitting.

.

Wear

Too long in service. Repeated winding

and overwinding of this rope on a drum while it was under heavy stress caused the unusually severe wear.

Wire RopeWire Rope

Wire Rope Sling Identification

Rated Load (rated capacity)

•Load test date

•Manufacturer’s name

•Periodic inspection due date

•Broken wires (10 in one lay or 5 in one strand)

•Severe corrosion

•Localized wear

•Reduction in outer wire

•Damaged end fittings

•Distortion, kinking, etc…

Wire rope – Permissible Stretch

6 strand wire rope 6 in. for 100 ft. length

8 strand wire rope 9 to 10 in. for 100 ft. length

Wire rope

Dia of rope Permissible reduction in dia. (inch)

3/4 3/64

7/8 to 11/8 1/16

11/4 to 11/2 3/32

Wire Rope Slings

single-rope legs

Wire Rope Slings

sling with single-rope legs, Torpedo loop-locks and choker hook

TWO LEGGED BRIDLE SLINGS

THREE LEGGED BRIDLE SLINGS

FOUR LEGGED BRIDLE SLINGS

Chain and Chain Sling

Parts of Chain Sling

Chain and Chain Sling

Single Chain Sling

Chain and Chain Sling

Double Chain Sling

Chain and Chain Sling

Triple & Quadruple Chain Sling

Chain and Chain Sling

Adjustable Chain Sling

Chain Sling Identification

•Chain Size

•Manufacturers Grade

•Rated load and angle

•Reach

•Number of legs

•Manufacturers name and trademark

•Next inspection

What should you avoid while using chain slings?

• impact loading: do not jerk the load when lifting or lowering the sling. This increases the actual stress on the sling.

• Do not drag chains.

• Do not splice a chain by inserting a bolt between two links.

• Do not shorten a chain with knots or by twisting.

• Do not force a hook over a link.

• Do not use homemade connections. Use only attachments designed for the chain.

• Do not heat treat or weld chain links: the lifting capacity will be reduced drastically.

                                                                       

Wear Cut

Twist or Bend

Stretched Links

Various defects in chain slings

Periodical inspection • Clean sling before inspection.

• Hang the chain up or stretch the chain out on a level floor in a well-lighted area. Remove all twists. Measure the sling length. Discard if a sling has been stretched.

• Make a link-by-link inspection and discard if

a. Wear exceeds 15% of a link diameter.

b. Cut,, cracked,, burned, or corrosion pitted

c. Twisted or bent

d. Stretched-- Links tend to get longer

Chain Sling Inspection Items Cracks, stretches, or deformed master links,

coupling links, chains or other components. 

One leg of a double or triple chain sling is longer than the others.  

Hooks have been opened more than 15% of the normal throat opening measured at the narrowest point or twisted more than 10 degrees from the plane of the unbent hook.  

Chain size at any point of any link is less than stated in the chart on the next slide, the sling shall be removed.  

Chain Slings

Only chain slings purchased from the manufacturer are allowed.

No homemade slings allowed!!

Special Precautions

• It is important to realize that the capacity of a sling decreases as the angle at which it is used to lift increases.

Rigging Devices

• Shackles

• Hooks

• Wire Rope Clips

• Wedge Sockets

• Eyebolts

• Spreader Beams

• Slings

Shackles

Recommended Not Recommended Recommended

Proper Use of Shackles

Never replace a shackle pin with a bolt

The load will bend the bolt

Avoid eccentric loads

Bad Good

Proper chocking of shackles.

Bad Good

Shackle Inspection

Hooks

• Manufacturers’ identification.

• Never weld on hooks.

• Working safety latch.

Wire Rope Clips

•The most common use of wire rope clips on cranes is at wedge and socket-end fittings.

•The clip does not provide strength to the wedge and socket connection.

•It is there to prevent the wedge from accidentally being released.

Installing Wire Rope Clips

Installed properly as to number, direction, spacing and torque.

Wedge Sockets

•Most common method of terminating ropes on cranes.

•All parts must match in size.

•Measure rope diameter to ensure proper size.

Wedge Socket - Correct Rope Installation

•Live end of the rope, the straight side of the socket and the pinhole all line up.

WINDING WIRE ROPE

Rigging

Basic Rules of Rigging

• Know the Weight

• Know the Capacity

HITCHES

STRAIGHT PULL

HITCHES

CHOCKER HITCH

HITCHES

BASKET HITCH

• Marked with the capacity and proof tested to 125 percent of that capacity.

• Load should not be left suspended or unattended

How Horizontal Angle Affects Sling Capacity

Note: A good operating practice is to keep sling angles from going below 60 degrees

Sling Angle Factor

Sling Angle Factor = L/H

Where: L = Length of the sling.

H = Height of the connection point from the horizontal plane of the load.

Sling Angles

Hook load increases on brake application during lowering

Loading lowering speed (ft/ min)

Stopping distance (ft)

Increase in hook

load

(%)

10 5 2

100 0.4 0.7 2.2

150 1.0 1.6 4.9

200 1.7 2.9 8.6

250 2.7 4.5 13.5

300 3.9 6.5 19.4

350 5.3 8.8 26.4

450 6.9 11.5 34.5Avoid rapid acceeration or deceleration of load

An illustration of the signals must be posted at the job site

Hand Signals

Sheave grooves may become grooved if cable’s nominal diameter is reduced,

indicating wear.

Safe Usage Practices Slings should be stored off

the floor and hung on racks whenever possible in a clean, dry environment.

 

Never drag slings across the floor. 

Safe Usage Practices (Cont.) Never shock load slings.

Keep loads balanced to prevent overloading slings.

Always lift loads straight up.

  Never rest a load on a sling,

or pinch a sling between the load and the floor.

A sling should not be pulled from under a load when the load is resting on the sling.

Make sure the hook is always over the center of gravity of the load before lifting it.

Do not apply a load to a twisted, knotted or kinked chain.

Do not force or hammer hooks or chains into position.

Safe Usage Practices (Cont.)

• Hands and Fingers shall not be placed between the sling and the load while the sling is being tightened around the load.

• Clean chains regularly as dirt and grit can cause excessive wear at the link bearing points.

• Never shorten a sling with knots, bolts or other makeshift devices.

 

• Protect the chain’s surface from contact with sharp corners, which can cause permanent damage through gouging or abnormal stress and wear.

Ropes, chains, and slings

• Factors affecting load capacity– Hitch type – Leg angle from vertical

• Other issues – Hook deformation (maximum 10° twist, 15%

throat opening)– Rope wear

• Consider replacement if more than 12 randomly distributed broken wires within a single strand within a single lay (ANSI B30.2)

– Chain deformation

Ropes, chains, and slings

• Selected controls– Proper selection of rigging materials– Proper use– Keeping loads within limits– Regular inspection/testing of rigging

components– Training of riggers

• Other issues– Hook retainers– Load capacity charts for field use

ReviewReview

Select the right sling for the job.Inspect slings prior to use,

removing from service any in question.

Remember the effect of sling angles on load capacities.

Properly store slings when finished to avoid damage.

ConcludeConclude

Associates in the direction of travel should be warned to move and remain clear of a lifted load at all times.

Loads should not be suspended over personnel below.

Under no circumstances may anyone ride the hook or load.

Directional movement should be made smoothly and deliberately. Avoid rapid movements in any direction.

Locate the hoist directly above the lifting point of the load before lifting.

Lower loads directly below the hoist.

Keep hoisting ropes vertical. Do not pull or push the load.

Maintain two full wraps of cable on the hoisting drum.

Never pull a hoist by the pendant cable

ConcludeConclude