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WIRE ROPES
INSTRUCTIONS - SLINGS - CARE & USE


Wire Rope Sling Use And Maintenance Information

Temperatures affect the working load limit of any wire rope slings as per the table below which must be taken into consideration when a sling is called to operate at elevated temperatures:

Percentage of WLL reduction compared to normal temperature operation

TERMINATION TYPE FERRULE
MATERIAL		 ROPE CORE REDUCTION OF WORKING LOAD LIMIT EXPRESSED AS % OF THE WLL OF THE SLING
Temperature T (ºC)
40-100 100-150 150-200 200-300 300-400 T>400
TURN BACK EYE ALUMINIUM FIBER 100 DO NOT USE DO NOT USE DO NOT USE DO NOT USE DO NOT USE
TURN BACK EYE ALUMINIUM STEEL 100 100 DO NOT USE DO NOT USE DO NOT USE DO NOT USE
FLEMISH EYE STEEL FIBER 100 DO NOT USE DO NOT USE DO NOT USE DO NOT USE DO NOT USE
FLEMISH EYE STEEL STEEL 100 100 90 75 65 DO NOT USE
HAND SPLICE - FIBER 100 DO NOT USE DO NOT USE DO NOT USE DO NOT USE DO NOT USE
HAND SPLICE - STEEL 100 100 90 75 65 DO NOT USE


The above reductions in the WLL of the wire rope slings are not permanent. Once the slings return to ambient temperature the WLL's are restored. Wire rope slings are not adversely affected by temperatures down to -400 ºC and no reduction to the WLL is necessary. For temperature below -400ºC please consult with us.

Wire rope slings should not be used either immersed in acidic solutions or exposed to acid fumes. Attention must be paid to the fact that certain production processes involve acidic solutions, fumes and sprays in which case expert consultation is needed. Advice must also be sought in the case of slings exposed to chemicals combined with high temperatures.

Slings for general lifting applications exclude hazardous conditions including offshore activities, lifting of persons and lifting of potentially dangerous loads such as molten metals, corrosive materials or fissile materials. In such cases the degree of hazard must be assessed by a competent person and the working load limit adjusted accordingly.

Before Taken Into Use:

    Before first use of the wire rope sling, please ensure that:
  1. The sling is precisely as ordered
  2. The manufacturer's certificate is available at hand
  3. The identification and WLL marking on the sling correspond to the information in the certificate
  4. Full details of the slings are recorded in a register of slings
  5. The actual use is to be as intended
Safe Use For The Wire Rope Sling:

Before starting the lift, please ensure that the load is free to move and not bolted down or obstructed in any way.

Special packing may be required where a rope may be come into contact with a load in order to protect either the rope or the load or both, since sharp corners of hard material may bend or damage the rope or the rope damages the load due to the high contact pressure. Corner protection must be used to prevent such damage. A tag line is recommended in order to prevent dangerous swaying of the load.

Special note: when loads are accelerated or decelerated, dynamic forces (shock loading) occur which increase the stresses in the rope. Such situations (which must definitely be avoided), arise from snatch or shock loading, ie when not taking up the slack rope before starting to lift or sudden stop during unloading etc.

Very essential is to know the exact mass of the load to be lifted before the lifting starts.

Stability Of The Load:

It is assumed that the attachment point of the hook is directly above the centre of gravity of the load. The following conditions must be met for loads with attachment points:

  1. For single leg and single endless wire rope slings the attachment point should be vertically above the centre of gravity
  2. For two leg wire rope slings the attachment points should be in either side of and above the centre of gravity
  3. For three and four leg wire rope slings the attachment points should be distributed in plan around the centre of gravity. It is preferable that the distribution should be equal (see symmetry in loading below) and that the attachment points are above the centre of gravity
If the attachment points in 1) or 2) above are at or below the centre of gravity, other lifting arrangements must be used.

Angles For Multi Leg Slings:

When using two, three and four leg wire rope slings the attachment points and sling configuration must be selected to achieve angles between the sling legs and the vertical within the range marked on the sling. Preferably all the angles to the vertical (â in the figure below) should be equal (see also below "symmetry"). Angles to the vertical less than 150 must be avoided, if possible, as they present a significantly greater risk of load imbalance.

All multi leg slings exert a horizontal component of force (see figure below) which increases as the angle between the legs increases. Care must be taken so that it is ensued that the load to be moved can resist this horizontal component of force ("squeeze" or "pressure" effect) without being damaged.





   1.   Loading of leg
   2.   Horizontal component of force

Hatched area: not covered by tag

The hatched area indicates angles greater than 600 to the vertical for which wire rope slings are not intended to be used.

Variation of wire rope sling leg loading with leg angle for a load of q





Connection Method:

A wire rope sling is usually attached to the load and the lifting machine by means of terminal fittings. Sling legs must not twisted or knotted. The lifting point must be seated well down in a hook, never on the point or wedged in the opening; the sling hook must be free to incline in any direction so as to avoid bending. For the same reason, the terminal fitting must be free to incline in any direction on the hook to which it is fitted.

The rope may be passed under or through the load to form a choke hitch or basket hitch (see figures below). When using basket hitch method and where it is necessary, due to the danger of the load tilting, to use more than one sling, this should preferably be done in conjunction with a lifting beam having two upper connections to the crane hook.

When a wire rope sling is used in a choke hitch, the rope must be allowed to assume its natural angle and must not be hammered down. When attaching the sling to the lifting hook, please make sure that there is adequate clearance to permit articulation and to prevent damage to the sling. Slings must never be hammered, wedged or forced into position. If there is not sufficient clearance, please fit a shackle between the sling and the hook.

In order to prevent the formation of kinks and subsequent weakening of the rope of slings having soft eye terminations, please make sure that the effective diameter of the shackle pin/hook is at least twice the diameter of the rope. In the case of a multi-leg sling, the tip of a sling hook should be directed outwards. No rope should be wrapped around a crane hook.

Sling Legs May Be Attached To The Load In Several Ways:

  1. Straight leg:

    In this case lower terminals are connected directly to the attachment points. Selection of hooks and attachment points must be such that the load is carried in the seat of the hook and tip loading of the hook is avoided.


  2. Choke hitch:

    In this case sling legs are passed through or under the load and the lower terminal back hooked or reeved onto the rope (see figure below). A single leg sling may also be used in a double choke hitch (see figure below). This method can, therefore, be used where no suitable attachment points are available and has the additional advantage that the wire rope sling legs tend to bind the load together. Where choke hitch is employed, the working load limit of the sling should be no more than 80% of that marked on it.

      If two or more wire rope sling legs are used in a choke hitch or a double choke hitch, special care should be exerted so that:

    1. If it is important, to avoid imparting a torque to the load, to align the chokes

      Or

    2. If it is important, to avoid the load rolling or moving laterally when first lifted, to ensure that (at least) one leg passes either side of the load.

      When endless slings are used, they must be placed in such a way that any joining ferrules or splices are in the free length of the sling.


  3. Basket hitch:

    There are two methods of forming a basket hitch; passing a single sling through a load or wrapping two slings around the load. The second method is not suitable where the slings are able to move towards each other when the load is lifted or when lifting loads which are not held together such as loose bundles; a choke hitch is preferred. Examples as shown in the figures below.



Choke Hitches (Single And Double)



Basket Hitches


Symmetry Of Loading:

The working load limits given in en 13414-1 for the wire rope slings have been determined on the basis that the loading of the slings is symmetrical. This means that when the load is lifted, the wire rope sling legs are symmetrically arranged in plan and subtend the same angles to the vertical (see figure below). In the case of three wire rope leg slings, if the legs are not symmetrically arranged in plan, the greatest tension will be in the leg where the sum of the plan angles to the adjacent legs is greatest. The same effect will occur in 4 leg wire rope slings except that the rigidity of the load should also be taken into account. With a rigid load the majority of the mass must be assumed to be taken by only three or even two legs with the remaining leg or legs serving only to balance the load (see figure below).



In the case of two, three and four-leg wire rope slings, if the legs subtend different angles to the vertical, the greatest tension will be in the leg with the smallest angle to the vertical. In the extreme case, if one leg is vertical, it will carry all the load.

If there is a lack of symmetry in plan and unequal angles to the vertical, the two effects will combine and may either be cumulative or tend to negate each other; but if the following is satisfied, the loading can be assumed to be symmetric providing the load to be lifted does not exceed 80% of the marked WLL:

  1. Wire rope sling leg angles to the vertical are all not less than 150; and
  2. Wire rope sling leg angles to the vertical are all within 150 to each other; and
  3. In the case of three and four wire rope slings, the sum of the plan angles to the adjacent legs is within 150 of each other.
If not all of the above parameters are satisfied then the loading should be considered as asymmetric and the lift referred to a competent person to establish the safe working load for the wire rope sling. Alternatively, in the case of asymmetric loading, the wire rope sling should be rated at half the marked WLL. If during a test lift the load is unstable, it should be lowered and the slinging arrangement changed.

Asymmetric Loading:

  1. Center of gravity
  2. High load in this leg
  3. Load P









Types of SlingNumber of Legs UsedFactor to apply to the marked WLL
2 LEG11/2
3 and 4 LEG22/3
3 and 4 LEG11/3
WORKING LOAD LIMIT WLL FACTORS



Taking into consideration all the above and the cumulative effects of de-rating, the method of slinging must be decided and a suitable wire rope sling(s) selected so that the mass to be lifted does not exceed the WLL.

Landing the load:

The landing site should be prepared. It must be ensured that the ground or floor is of adequate strength to take the load taking account of any voids, ducts, pipes etc which may be damaged or collapse. It must also be ensured that there is adequate access to the site and that it is clear of any unnecessary obstacles and people. It is preferable to use timber bearers or similar material to avoid trapping the sling or to protect the floor or load or to ensure the stability of the load when landed.

The load should be landed carefully ensuring that hands and feet are kept clear. Care should be taken to avoid trapping the wire rope sling beneath the load as this may damage it. Before allowing the rope to become slack, the load should be checked to ensure that it is properly supported and stable. This is especially important when several loose objects are in a basket hitch and choke hitch. When the load is safely landed, the wire rope sling should be carefully removed to avoid damage or snagging or cause the load to topple over. The load should not be rolled off the sling as this may damage the sling.

Storage Of Wire Rope Slings:

When not in use, wire rope slings should normally be kept on a properly designed rack. They should not be left lying on the ground where they may be damaged.

If the wire rope slings are to be left suspended from a crane hook, the sling hooks should be engaged in an upper link to reduce the risk of sling legs swinging freely or snagging.

If it is likely that wire rope slings will be out of use for some time they should be cleaned, dried and protected from corrosion, ie lightly oiled.

Inspection, Thorough Examination And Maintenance General Data:

During service, wire rope slings are subjected to conditions that affect their safety. It is therefore necessary to ensure, as far as is reasonably practicable, that the sling is safe for continued use.

The sling must be inspected for any obvious signs of deterioration before each use. If at any time there is reason to doubt the safe condition of the sling, it must be withdrawn from service and subjected to a thorough examination. If the tag or label identifying the sling and its working load limit becomes detached and the necessary information is not marked on the master link, or by some other means, the sling must be withdrawn from service.

Inspection Before Each Use:

    An inspection is a visual examination on the condition of the sling to identify any obvious damage or deterioration that might affect its fitness for use. The sling must be withdrawn from service and referred to a competent person for thorough examination if any of the following is observed before each use:

  1. Illegible sling markings, ie sling identification and/or working load limit
  2. Wear, distortion and/or cracking of the upper or lower terminals and or ferrules
  3. Concentration(s) of broken wires
  4. Severe rope distortion, such as kinks or protrusion of the core
  5. Significant rope wear
  6. Corrosion
  7. Heat damage


Thorough Examination And Discard Criteria


General:

A thorough examination must be carried out at intervals not exceeding 12 months. This intervals must be less where deemed necessary in the light of service conditions.

In order to facilitate examination, slings may need to be cleaned so as to be free from oil, dirt and rust prior to examination. This can usually be accomplished by using a wire brush. Other methods may be used providing that the parent metal is not damaged. Methods to avoid are those using acids, overheating or removal of metal.

Records of such examinations must be maintained.

    The sling must be withdrawn from service if any of the following are present, reached or exceeded:

  1. The sling markings (such as information on the sling identification and/or the WLL) are illegible.
  2. Wear, distortion or cracking of the upper or lower terminals. Particular attention should be paid to signs of opening up, distortion or cracking of the hook, distortion and wear of links or the closing of the thimble, indications that the sling may have been overloaded.
  3. Wear, distortion or cracking of ferrules or the pulling out of a splice.
  4. Broken wires: this is a detrimental condition, because of the possibility of injury to the user's hands and of the loss of strength in the rope. Broken wires are usually caused by mechanical damage, although corrosion may also be a factor. The appearance of well distributed broken wires may have no marked effect on the strength of the sling but the discard criteria (see below) must be adopted for randomly distributed broken wires and concentrated broken wires resp. In order to prevent injury to the user's hands, protruding wires can be broken off in the valleys between the strands by reverse bending the wire, with the help of pliers, until fracture occurs. Such actions must be recorded.
  5. Randomly distributed broken wires: 6 randomly distributed broken outer wires in a length of 6d but no more than 14 randomly distributed broken wires in a length of 30d, where d is the nominal rope diameter.
  6. Concentrated broken wires: 3 adjacent broken outer wires in one strand .
  7. Rope distortion: kinking, crushing, birdcaging or core protrusion or other damage which distorts the rope structure. The main thing to look for is wires or strands that are pushed out of their original positions in the rope. Slight bends in a rope where wires or strands are still relatively in their original positions would not be considered serious damage.
  8. Rope wear: 10% of the nominal rope diameter (d).
  9. Corrosion: pitting of the wires or loss of flexibility of the rope due to severe internal corrosion. Corrosion may occur where slings have been improperly stored or have been used in particularly corrosive conditions, such as moving loads in and out of acid/alkali baths. The effect is readily identified through the loss of flexibility and roughness to the touch. While light surface rusting is unlikely to affect the rope strength, it may be indicative of internal corrosion, the effect of which is not predictable.
  10. Heat damage as evidenced by discoloration of the wires, loss of lubrication or pitting of the wires caused by electric arcing.


Any replacement component or part of the wire rope sling must be in accordance with the appropriate European standard for that component or part. Components that are cracked, visibly distorted or twisted, severely corroded or have deposits that cannot be removed must be discarded and replaced. Minor damage such as nicks and gouges to terminal fittings may be removed by careful grinding or filing. The surface must blend smoothly into adjacent material without abrupt change of section. The complete removal of the damage must not reduce the thickness of the section at that point to less than the manufacturer's specified minimum dimensions or by more than 10% of nominal thickness of the section.

Various warnings & tips for a safer lifting:

Attention must be paid in the condition of the sling so that it doesn't show a deformation as shown. When a loop is "pulled through" it forms a kink which permanently deforms a wire rope by freezing or locking wires and strands. This prevents them from sliding and adjusting, and reduces rope strength. A "dogleg" is a "set" which occurs when a wire rope sling is pulled down snug against a load. A dogleg usually can be "rolled back" or turned inside out, and usefulness of the sling restored, since strands can still adjust. Eye deformation is ordinarily not detrimental to sling strength as long as there are no broken wires or gross distortion of the lay of the strands. An eye has two legs, so has adequate strength for the load the body can carry. A sling must be retired when distortion locks the strands or flattens the rope in the eye so strands cannot move and adjust.

Warning: hand spliced slings must not be used in lifts where the sling may rotate and cause the wire rope to unlay. Use a tag line to keep the load in balance upon lifting.

Download the aforementioned information:

  • INSTRUCTIONS FOR WIRE ROPE SLING USE & MAINTENANCE
  • INSTRUCTIONS FOR WIRE ROPE SLING USE & MAINTENANCE (GREEK)
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