2 Types of Slings Wire Rope Slings Chain Slings Synthetic Web Slings
3 Ropes, chains, and slings Primary hazard is structural failure due to:Overloading (“the weakest link”)Deterioration and/or wearEnvironmental exposureImproper riggingAbuse
4 Natural fibre ropes IS: 1084—1969 Manila Rope IS: 1321—1970 Sisal Rope MANILA — Black YarnGrade-I SPECIAL QUALITY ALL THE THREE STRANDSGrade-II STANDARD QUALITY ALL THE TWO STRANDSGrand-III MERCHANT QUALITY ONE STRANDSISAL Red or Green YARN in one strand
5 SWL of Fibre ropes Value Condition SWL ONE Rope of which original Fibre strength is not reducedSame as per new RopeTWORope which has been used and shows slight external wear and chafe80% of the NewTHREERope which has fair amount of usage,clear indication of internal and external wear, loosening of strandsNOT TO BE USED FOR HOISTING
6 Fibre ropesDANGEROnce a Fibre Rope is condemned it should be cut with a knife so as to ensure that it should not be used again.
7 Internal wear by Repeated Flexing Fibre ropesCauses of DeteriorationROUGH USERubbing against sharp edgesDamaged groves of sheavesDragging from under the loadHARMFUL CONTACTWith water, oil, chemicals and heatBAD STORAGEHeap on wet floor, poorly ventilated godownInternal wear by Repeated Flexing
8 Synthetic Fibre ropes Advantages IS: 4572– 1968 Polyamide (Nylon Filament Rope)IS: 5175– 1969 Poly Propylene RopeIS: 8674– 1978 Polyethylene RopeAdvantagesLight in WeightHigher StrengthIncreased Resistance to Repeated Bending, Flexing and AbrasionResistance to water andChoice of Selection
9 Wire Rope and Wire Rope Slings Components of Wire Rope
12 CrushingBecause of loose winding on drum, rope was pulled in between underlying wraps and crushed out of shape.
13 BirdcagingThe sudden release of a load cause birdcaging.Here individual strands open away from each other, displacing the core.
14 Locking of strandsPremature breakage of wires resulted from "locking" of strands, which was caused by insufficient lubrication.
15 AbrasionNeglect of periodical inspection left this rope in service too long, resulting in considerable abrasion.
16 KinkingKink or "dog leg“ was caused by improper handling and/or installation. A kink causes excessive localized or spot abrasion.
17 Reverse bendingRunning this rope over one sheave and under another caused fatigue breaks in wires.
18 PittingToo much exposure combined with surface wear and loss of lubrication caused corrosion and pitting..
19 Too long in service. Repeated winding WearToo long in service. Repeated windingand overwinding of this rope on a drum while it was under heavy stress caused the unusually severe wear.
20 Wire Rope Wire Rope Sling Identification Rated Load (rated capacity) Load test dateManufacturer’s namePeriodic inspection due dateBroken wires (10 in one lay or 5 in one strand)Severe corrosionLocalized wearReduction in outer wireDamaged end fittingsDistortion, kinking, etc…
21 Wire rope – Permissible Stretch 6 strand wire rope6 in. for 100 ft. length8 strand wire rope9 to 10 in. for 100 ft. length
22 Permissible reduction in dia. (inch) Wire ropeDia of ropePermissible reduction in dia. (inch)3/43/647/8 to 11/81/1611/4 to 11/23/32
33 Chain Sling Identification Chain SizeManufacturers GradeRated load and angleReachNumber of legsManufacturers name and trademarkNext inspection
34 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.
35 Various defects in chain slings WearCutStretched LinksTwist or Bend
36 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 ifWear exceeds 15% of a link diameter.Cut,, cracked,, burned, or corrosion pittedTwisted or bentStretched-- Links tend to get longer
37 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.
38 Chain SlingsOnly chain slings purchased from the manufacturer are allowed. No homemade slings allowed!!
39 Special PrecautionsIt is important to realize that the capacity of a sling decreases as the angle at which it is used to lift increases.
48 Wire Rope ClipsThe 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.
49 Installing Wire Rope Clips Installed properly as to number, direction, spacing and torque.
50 Wedge Sockets Most common method of terminating ropes on cranes. All parts must match in size.Measure rope diameter to ensure proper size.
51 Wedge Socket - Correct Rope Installation Live end of the rope, the straight side of the socket and the pinhole all line up.
61 Hook load increases on brake application during lowering Loading lowering speed (ft/ min)Stopping distance (ft)Increase in hook load(%)10521000.40.72.21501.01.64.92001.72.98.62502.74.513.53003.96.519.43505.38.826.44506.911.534.5Avoid rapid acceeration or deceleration of load
65 Hand SignalsAPPLICABLE OSHA STANDARD(a)(4) Hand signals to crane and derrick operators shall be those prescribed by the applicable ANSI standard for the type of crane in use. An illustration of the signals shall be posted at the job site.These charts are available in other languages.An illustration of the signals must be posted at the job site
66 Sheave grooves may become grooved if cable’s nominal diameter is reduced, indicating wear.
70 Safe Usage PracticesSlings should be stored off the floor and hung on racks whenever possible in a clean, dry environment.Never drag slings across the floor.
71 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.
72 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.
73 Ropes, chains, and slings Factors affecting load capacityHitch typeLeg angle from verticalOther issuesHook deformation (maximum 10° twist, 15% throat opening)Rope wearConsider replacement if more than 12 randomly distributed broken wires within a single strand within a single lay (ANSI B30.2)Chain deformation
74 Ropes, chains, and slings Selected controlsProper selection of rigging materialsProper useKeeping loads within limitsRegular inspection/testing of rigging componentsTraining of riggersOther issuesHook retainersLoad capacity charts for field use
75 Review 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.
76 ConcludeAssociates 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.
77 ConcludeLocate 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