Presentation on theme: "Safe Slinging Practices www.prothermindia.com. Types of Slings 1)Wire Rope Slings 2)Chain Slings 3)Synthetic Web Slings www.prothermindia.com."— Presentation transcript:
Safe Slinging Practices
Types of Slings 1)Wire Rope Slings 2)Chain Slings 3)Synthetic Web Slings
Ropes, 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 ropes IS: Manila Rope IS: Sisal Rope MANILA Black Yarn Grade-ISPECIAL QUALITY ALL THE THREE STRANDS Grade-IISTANDARD QUALITY ALL THE TWO STRANDS Grand-IIIMERCHANT QUALITY ONE STRAND SISALRed or Green YARN in one strand
SWL of Fibre ropes ValueConditionSWL ONERope of which original Fibre strength is not reduced Same as per new Rope TWORope which has been used and shows slight external wear and chafe 80% of the New THREERope which has fair amount of usage,clear indication of internal and external wear, loosening of strands NOT TO BE USED FOR HOISTING
Fibre ropes Once a Fibre Rope is condemned it should be cut with a knife so as to ensure that it should not be used again.
Causes of Deterioration Fibre ropes ROUGH USERubbing against sharp edges Damaged groves of sheaves Dragging from under the load HARMFUL CONTACTWith water, oil, chemicals and heat BAD STORAGEHeap on wet floor, poorly ventilated godown Internal wear by Repeated Flexing
Synthetic Fibre ropes IS: 4572– 1968Polyamide (Nylon Filament Rope) IS: 5175– 1969Poly Propylene Rope IS: 8674– 1978Polyethylene 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 Slings 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 Rope Wire Rope Sling Identification Rated Load (rated capacity) Load test date Manufacturers 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 rope6 in. for 100 ft. length 8 strand wire rope9 to 10 in. for 100 ft. length
Wire rope Dia of ropePermissible reduction in dia. (inch) 3/43/64 7/8 to 11/81/16 11/4 to 11/23/32
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.
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
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.
Hook load increases on brake application during lowering Loading lowering speed (ft/ min) Stopping distance (ft) Increase in hook load (%) Avoid 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 cables 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 chains 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
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.
Conclude 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 Conclude