safe working load of wire rope sling quotation

Rated load based on pin diameter no larger than one half the natural eye length or not less than the nominal sling diameter. Basket hitch capacity based on minimum D/d ratio of 25/1. For choker hitch, the angle of choke shall be 120 degrees or greater. For sling angles other than those shown, use the rated load for the next lower angle or a qualified person shall calculate the rated load. Horizontal sling angles of less than 30 degrees are not recommended. The capacity of a bridle at a 30 degree horizontal is same as single vertical leg.

SWL, NWL, MBS — all of the acronyms can get very confusing. Don’t fret – we’re here to clear things up when it comes to safe working load limits and the terms associated with it.

Safe Working Load (SWL) sometimes stated as the Normal Working Load (NWL) is the mass or force that a piece of lifting equipment, lifting device or accessory can safely utilize to lift, suspend, or lower a mass without fear of breaking. Usually marked on the equipment by the manufacturer and is often 1/5 of the Minimum Breaking Strength (MBS) although other fractions may be used such as 1/4, 1/6 and 1/10.[1][2][3]

Other synonyms include Working Load Limit (WLL), which is the maximum working load designed by the manufacturer. This load represents a force that is much less than that required to make the lifting equipment fail or yield, also known as the Minimum Breaking Load (MBL). SWL or WLL are calculated by dividing MBL by a safety factor (SF). An example of this would be a chain that has a MBL of 2000 lbf (8.89 kN) would have a SWL or WLL of 400 lbf (1.78 kN) if a safety factor of 5 (5:1, 5 to 1, or 1/5) is used.

Here at Industrial Rope Supply, we are not only committed to providing you with a quality product, but also with all the information needed to insure safety comes first on every job. Have safety questions on a product purchased from us? Contact us today and we’ll be happy to talk you through and/or provide you with the safety materials needed.

Wire rope is often used in slings because of its strength, durability, abrasion resistance and ability to conform to the shape of the loads on which it is used. In addition, wire rope slings are able to lift hot materials.

Wire rope used in slings can be made of ropes with either Independent Wire Rope Core (IWRC) or a fiber-core. It should be noted that a sling manufactured with a fiber-core is usually more flexible but is less resistant to environmental damage. Conversely, a core that is made of a wire rope strand tends to have greater strength and is more resistant to heat damage.

Wire rope may be manufactured using different rope lays. The lay of a wire rope describes the direction the wires and strands are twisted during the construction of the rope. Most wire rope is right lay, regular lay. This type of rope has the widest range of applications. Wire rope slings may be made of other wire rope lays at the recommendation of the sling manufacturer or a qualified person.

Wire rope slings are made from various grades of wire rope, but the most common grades in use are Extra Improved Plow Steel (EIPS) and Extra Extra Improved Plow Steel (EEIPS). These wire ropes are manufactured and tested in accordance with ASTM guidelines. If other grades of wire rope are used, use them in accordance with the manufacturer"s recommendations and guidance.

When selecting a wire rope sling to give the best service, consider four characteristics: strength, ability to bend without distortion, ability to withstand abrasive wear, and ability to withstand abuse.

Rated loads (capacities) for single-leg vertical, choker, basket hitches, and two-, three-, and four-leg bridle slings for specific grades of wire rope slings are as shown in Tables 7 through 15.

Rated loads for a sling in a choker hitch are the values shown in Table 7, 9, 11, 13, 14, or 15, provided that the angle of the choke is 120 degrees or more (Fig. 2). Use the values in Fig. 2 or those from the sling manufacturer or a qualified person for angles of choke less than 120 degrees.

Ensure that slings made of rope with 6×19 and 6x37 classifications and cable slings have a minimum clear length of rope 10 times the component rope diameter between splices, sleeves, or end fittings unless approved by a qualified person,

Ensure that braided slings have a minimum clear length of rope 40 times the component rope diameter between the loops or end fittings unless approved by a qualified person,

Ensure that grommets and endless slings have a minimum circumferential length of 96 times the body diameter of the grommet or endless sling unless approved by a qualified person, and

Perform welding of handles or other accessories to end attachments, except covers to thimbles, before assembly of the sling. Ensure that welded end attachments are proof tested by the manufacturer or a qualified person. Retain the certificates of proof test and make them available for examination.

Do not use wire rope clips to fabricate wire rope slings, except where the application precludes the use of prefabricated slings and where the sling is designed for the specific application by a qualified person,

Although OSHA"s sling standard does not require you to make and maintain records of inspections, the ASME standard contains provisions on inspection records.[3]

Use damaged slings only after they are repaired, reconditioned, and proof tested by the sling manufacturer or a qualified person using the following criteria:

Ensure that wire rope slings have suitable characteristics for the type of load, hitch, and environment in which they will be used and that they are not used with loads in excess of the rated load capacities described in the appropriate tables. When D/d ratios (Fig. 4) are smaller than those listed in the tables, consult the sling manufacturer. Follow other safe operating practices, including:

Ensure that multiple-leg slings are selected according to Tables 7 through 15 when used at the specific angles given in the tables. Ensure that operations at other angles are limited to the rated load of the next lower angle given in the tables or calculated by a qualified person,

When D/d ratios (see Fig. 6) smaller than those cited in the tables are necessary, ensure that the rated load of the sling is decreased. Consult the sling manufacturer for specific data or refer to the WRTB (Wire Rope Technical Board) Wire Rope Sling Users Manual, and

Ensure that all portions of the human body are kept away from the areas between the sling and the load and between the sling and the crane or hoist hook,

When using a basket hitch, ensure that the legs of the sling contain or support the load from the sides, above the center of gravity, so that the load remains under control,

Ensure that the load applied to the hook is centered in the base (bowl) of the hook to prevent point loading on the hook, unless the hook is designed for point loading,

Before initial use, ensure that all new swaged-socket, poured-socket, turnback-eye, mechanical joint grommets, and endless wire rope slings are proof tested by the sling manufacturer or a qualified person.

Permanently remove from service fiber-core wire rope slings of any grade if they are exposed to temperatures in excess of 180 degrees F (82 degrees C).

Follow the recommendations of the sling manufacturer when you use metallic-core wire rope slings of any grade at temperatures above 400 degrees F (204 degrees C) or below minus 40 degrees F (minus 40 degrees C).

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A lifting sling has a purpose, which is to move bulky, large, and heavy loads. Slings are used because lifting without them can be difficult and sometimes not even possible. Lifting slings makes a direct connection between the load and the lifting equipment being used. Although these slings are used to make lifting more accessible, they can make lifting more dangerous if the straps are misused. Anytime a sling is used for lifting, it is essential that users take concrete steps and precautions.

A lifting sling should be inspected before every use (including the first time). A damaged sling can break while lifting loads. Dropping loads can harm people, products, and the environment.

Different sling styles and sizes exist, and so not all can be used interchangeably. When it comes to lifting tools, you need the right sling for the job. Webbing slings have a full surface, which can help to protect larger loads.

Never exceed the working limit for a load. All lifting devices, like cranes and hoists, are rated for the weight they can carry. Lifting slings are calculated similarly. If you are lifting an object that is roughly 18 tonnes, you will want to acquire slings that have a WLL (working load limit) of 20 tonnes.

Our wire rope slings comply with the Supply of Machinery (Safety) Regulations. Wire rope fittings and steel rope are matched up against each other to suit the required load. They go through thorough quality assurances and are clearly labelled to maximise safety. Slinging arrangements are made up to order, in accordance with your specifications.

Various end fittings and end fitting combinations are available for online quotation, where you can choose the complete configuration of the sling that you require. If you require any additional features such as fibre core, or the construction of the wire e.g. 6x36 IWRC, please add this into the additional information box at the end of constructing your wire ropes.

The working load limits of slings made from general engineering ropes to BS EN 12385-4 should conform to BS EN 13414-1: 2003. Note that the working load limits shown are based on the assumption that soft-eyes of single-part slings are used over bearing points of not less than twice the normal diameter of the rope. All sling ropes must be ordinary lay.

The Safe Working Load will normally be equal to the Working Load Limit but in some circumstances it may be less e.g. If the sling is used in choke hitch SWL=WLL x 0.8.

BS EN 13414-1 covers only those sling assemblies that have legs of equal nominal length, diameter, construction and tensile grade. While sling assemblies with legs of unequal length may be made up generally in accordance with the requirements of BS EN 13414-1, it must be stressed that their rating requires special consideration by a competent person.

In all cases, where hooks or shackles are used, the WLL of the hooks and shackles shall never be less than the WLL of the leg which they are fitted to.

When using multi-leg sling assemblies, remember that increasing the angles between the legs will increase the load in each leg. Examine all slings before use, and discard any that are defective. Slings which are found to be unfit for use should be destroyed by cutting them up - not put on a refuse dump. ‘Hooking back’ to the leg of a sling is not recommended. The Safe Working Load of slings is affected by the method of usage. Check that the crane hook is positioned over the loads centre of gravity to prevent swinging when the load is being raised. Correct signals, according to the recognised code, should be given to the crane driver. The signals must be given by the person responsible for the lift and nobody else.

Keep the wire rope sling away from welding and flame cutting operations. The Law requires that all lifting tackle must be examined by a competent person at regular intervals. Users should not store away slings and regard them as their own private slinging assemblies, as this could lead to them being overlooked at inspection time.

Large Loads Require Large Slings Whatever the load you are lifting. YuanBo Wire Rope Factory can supply a steel wire rope sling to do the task. Sling up to 12" (305mm) diameter can be supplied with minimum braking loads up to tons. There arethree distinct types of Wire Rope Sling.

Slings manufactured from cable laid ropes, 4" diameter to 12" diameter. hand spliced or by combination of hand splicing and socketing with eye at each end.

Slings manufactured from 6 strand equal laid ropes. up to 3.5 " diameter with soft eyes spliced each end. terminated by either hand splicing or mechanical means.

The most common size: wire rope slings having soft eyes at both end used for heavy lifting operations with safety factor of 7, length 6m, 12m, 16m, 20m, and the swl from 5 ton to 40 ton.

Wire rope slings can be used in many different industries such as general manufacturing, automotive, metals production and petroleum and gas. Wire rope slings are strong and flexible and can be resistant to abrasion and corrosion. Wire rope slings should be inspected by trained and qualified service personnel to minimize the risk or failure and to stay compliant with regulations.

Employers must use only wire-rope slings that have permanently affixed and legible identification markings as prescribed by the manufacturer, and that indicate the recommended safe working load for the type(s) of hitch(es) used, the angle upon which it is based, and the number of legs if more than one.

Cable laid and 6 × 19 and 6 × 37 slings shall have a minimum clear length of wire rope 10 times the component rope diameter between splices, sleeves or end fittings.

Fiber core wire rope slings of all grades shall be permanently removed from service if they are exposed to temperatures in excess of 200 °F. When nonfiber core wire rope slings of any grade are used at temperatures above 400 °F or below minus 60 °F, recommendations of the sling manufacturer regarding use at that temperature shall be followed.

All welded end attachments shall not be used unless proof tested by the manufacturer or equivalent entity at twice their rated capacity prior to initial use. The employer shall retain a certificate of the proof test, and make it available for examination.

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

Konecranes inspectors and technicians can inspect the slings and other rigging equipment in your facility to determine if it meets OSHA standards. The Konecranes Slings and Accessories Inspection checks non-maintainable load lifting attachments and accessories to identify deficiencies and deviations from local statutory safety and health regulations. The inspection service utilizes radio frequency identification (RFID) tags to record load lifting attachment inspection data and a smartphone app to help quickly and reliably identify attachments.

*The foregoing OSHA regulations are not intended to be a comprehensive overview of all applicable regulations pertaining to the designated topic. State laws may mandate different safety and maintenance standards. Accordingly, please consult applicable state laws as well as original equipment manufacturer specifications for further guidance. The statements and descriptions contained herein constitute the opinion/recommendation of the seller and are not intended to create any express warranties.

Employers must not load a sling in excess of its recommended safe working load as prescribed by the sling manufacturer on the identification markings permanently affixed to the sling.

Each day before being used, the sling and all fastenings and attachments shall be inspected for damage or defects by a competent person designated by the employer. Additional inspections shall be performed during sling use, where service conditions warrant. Damaged or defective slings shall be immediately removed from service

ATTACHMENTSHooks, rings, oblong links, pear shaped links, welded or mechanical coupling links or other attachments shall have a rated capacity at least equal to that of the alloy steel chain with which they are used or the sling shall not be used in excess of the rated capacity of the weakest component.

INSPECTIONSIn addition to the inspection required by paragraph (d) of this section, a thorough periodic inspection of alloy steel chain slings in use shall be made on a regular basis, to be determined on the basis of (A) frequency of sling use; (B) severity of service conditions; (C) nature of lifts being made; and (D) experience gained on the service life of slings used in similar circumstances. Such inspections shall in no event be at intervals greater than once every 12 months.

The employer shall make and maintain a record of the most recent month in which each alloy steel chain sling was thoroughly inspected, and shall make such record available for examination.

The thorough inspection of alloy steel chain slings shall be performed by a competent person designated by the employer, and shall include a thorough inspection for wear, defective welds, deformation and increase in length. Where such defects or deterioration are present, the sling shall be immediately removed from service.

PROOF TESTINGThe employer shall ensure that before use, each new, repaired, or reconditioned alloy steel chain sling, including all welded components in the sling assembly, shall be proof tested by the sling manufacturer or equivalent entity, in accordance with paragraph 5.2 of the American Society of Testing and Materials Specification A391-65, which is incorporated by reference as specified in Sec. 1910.6 (ANSI G61.1-1968). The employer shall retain a certificate of the proof test and shall make it available for examination.

SAFE OPERATING TEMPERATURESEmployers must permanently remove an alloy steel-chain slings from service if it is heated above 1000°F. When exposed to service temperatures in excess of 600°F, employers must reduce the maximum working-load limits permitted by the chain manufacturer in accordance with the chain or sling manufacturer’s recommendations.

REPAIRING AND RECONDITIONING ALLOY STEEL CHAIN SLINGSWorn or damaged alloy steel chain slings or attachments shall not be used until repaired. When welding or heat testing is performed, slings shall not be used unless repaired, reconditioned and proof tested by the sling manufacturer or an equivalent entity.

Slings shall be removed from service if hooks are cracked, have been opened more than 15 percent of the normal throat opening measured at the narrowest point or twisted more than 10 degrees from the plane of the unbent hook.

SLING IDENTIFICATION Employers must use only wire-rope slings that have permanently affixed and legible identification markings as prescribed by the manufacturer, and that indicate the recommended safe working load for the type(s) of hitch(es) used, the angle upon which it is based, and the number of legs if more than one.

MINIMUM SLING LENGTHSCable laid and 6×19 and 6×37 slings shall have a minimum clear length of wire rope 10 times the component rope diameter between splices, sleeves or end fittings.

SAFE OPERATING TEMPERATURESFiber core wire rope slings of all grades shall be permanently removed from service if they are exposed to temperatures in excess of 200°F. When nonfiber core wire rope slings of any grade are used at temperatures above 400°F or below minus 60°F, recommendations of the sling manufacturer regarding use at that temperature shall be followed.

All welded end attachments shall not be used unless proof tested by the manufacturer or equivalent entity at twice their rated capacity prior to initial use. The employer shall retain a certificate of the proof test, and make it available for examination.

REMOVAL FROM SERVICEWire rope slings shall be immediately removed from service if any of the following conditions are present:Ten randomly distributed broken wires in one rope lay, or five broken wires in one strand in one rope lay.

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

SLING IDENTIFICATIONEach metal mesh sling shall have permanently affixed to it a durable marking that states the rated capacity for vertical basket hitch and choker hitch loadings.

SLING TESTINGAll new and repaired metal mesh slings, including handles, shall not be used unless proof tested by the manufacturer or equivalent entity at a minimum of 1 1/2 times their rated capacity. Elastomer impregnated slings shall be proof tested before coating.

SAFE OPERATING TEMPERATURESMetal mesh slings which are not impregnated with elastomers may be used in a temperature range from minus 20°F to plus 550°F without decreasing the working load limit. Metal mesh slings impregnated with polyvinyl chloride or neoprene may be used only in a temperature range from zero degrees to plus 200°F. For operations outside these temperature ranges or for metal mesh slings impregnated with other materials, the sling manufacturer’s recommendations shall be followed.

Once repaired, each sling shall be permanently marked or tagged, or a written record maintained, to indicate the date and nature of the repairs and the person or organization that performed the repairs. Records of repairs shall be made available for examination.

REMOVAL FROM SERVICEMetal mesh slings shall be immediately removed from service if any of the following conditions are present:A broken weld or broken brazed joint along the sling edge.

SLING IDENTIFICATIONEmployers must use natural and synthetic fiber-rope slings that have permanently affixed and legible identification markings stating the rated capacity for the type(s) of hitch(es) used and the angle upon which it is based, type of fiber material, and the number of legs if more than one.

SAFE OPERATING TEMPERATURESNatural and synthetic fiber rope slings, except for wet frozen slings, may be used in a temperature range from minus 20°F to plus 180°F without decreasing the working load limit. For operations outside this temperature range and for wet frozen slings, the sling manufacturer’s recommendations shall be followed.

SPLICINGSpliced fiber rope slings shall not be used unless they have been spliced in accordance with the following minimum requirements and in accordance with any additional recommendations of the manufacturer:

In manila rope, eye splices shall consist of at least three full tucks, and short splices shall consist of at least six full tucks, three on each side of the splice center line.

In synthetic fiber rope, eye splices shall consist of at least four full tucks, and short splices shall consist of at least eight full tucks, four on each side of the center line.

Strand end tails shall not be trimmed flush with the surface of the rope immediately adjacent to the full tucks. This applies to all types of fiber rope and both eye and short splices. For fiber rope under one inch in diameter, the tail shall project at least six rope diameters beyond the last full tuck. For fiber rope one inch in diameter and larger, the tail shall project at least six inches beyond the last full tuck. Where a projecting tail interferes with the use of the sling, the tail shall be tapered and spliced into the body of the rope using at least two additional tucks (which will require a tail length of approximately six rope diameters beyond the last full tuck).

For all eye splices, the eye shall be of such size to provide an included angle of not greater than 60 degrees at the splice when the eye is placed over the load or support.

REMOVAL FROM SERVICENatural and synthetic fiber rope slings shall be immediately removed from service if any of the following conditions are present:Abnormal wear.

ATTACHMENTS OF END FITTINGS TO WEBBING AND EYE FORMATIONStitching shall be the only method used to attach end fittings to webbing and to form eyes. The thread shall be in an even pattern and contain a sufficient number of stitches to develop the full breaking strength of the sling.

SAFE OPERATING TEMPERATURESSynthetic web slings of polyester and nylon shall not be used at temperatures in excess of 180°F. Polypropylene web slings shall not be used at temperatures in excess of 200°F.

Each repaired sling shall be proof tested by the manufacturer or equivalent entity to twice the rated capacity prior to its return to service. The employer shall retain a certificate of the proof test and make it available for examination.

REMOVAL FROM SERVICESynthetic web slings shall be immediately removed from service if any of the following conditions are present:Acid or caustic burns;

The goal of a sling inspection is to evaluate remaining strength in a sling which has been used previously to determine if it is suitable for continued use.

Specific inspection intervals and procedures are required by the Occupational Safety and Health Act (OSHA) and by ANSI B30.9 Regulations, and the responsibility for performance of inspections is placed squarely upon the sling user by Federal Legislation.

As a starting point, the same work practices which apply to all “working” wire ropes apply to wire rope which has been fabricated into a sling.Therefore, a good working knowledge of wire rope design and construction will be not only useful but essential in conducting a wire rope sling inspection.

But because wire rope is a rather complex machine, no precise rules can be given to determine exactly when a wire rope sling should be replaced. There are many variables, and all must be considered.

Broken Wires: For single-part slings. 10 randomly distributed broken wires in one rope lay, or five broken wires in one strand on one rope lay. For multi-part slings these same criteria apply to each of the component ropes.For the inspection, a broken wire shall only be counted once; that is, each break should have two ends.

Metal Loss: Wear or scraping of one-third the original diameter of outside individual wires. This is quite difficult to determine on slings and experience should be gained by the inspector by taking apart old slings and actually measuring wire diameters.

Distortion: Kinking, crushing, birdcaging 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. But good judgement is indicated.

Bent Hooks: No more than 15 percent over the normal throat openings, measured at the narrowest point, or twisting of more than 10 degrees is permissible.

Metal Corrosion: Severe corrosion of the rope or end attachments which has caused pitting or binding of wires should be cause for replacing the sling. Light rusting usually does not affect strength of a sling, however. In addition to these seven conditions specified by OSHA, the following are also important:

Pulled Eye Splices: Any evidence that eye splices have slipped, tucked strands have moved, or pressed sleeves show serious damage may be sufficient cause to reject a sling.

Unbalance: A very common cause of damage is the kink which results from pulling through a loop while using a sling, thus causing wires and strands to be deformed and pushed out of their original position. This unbalances the sling, reducing its strength.

Disposition of Retired Slings: the best inspection program available is of no value if slings which are worn out and have been retired are not disposed of properly. When it is determined by the inspector that a sling is worn out or damaged beyond use, it should be tagged immediately DONOTUSE. This sling should then be destroyed as soon as possible by cutting the eye and fittings from the rope with a torch. This will help assure that an employee will not mistakenly use a sling which has been retired from service.

Equipment used in lifting or supporting materials, including cranes and load-bearing structures, uses rigging made of chains, synthetic or wire ropes. A proof load test is a process that requires the lift of a specific type of material (the rope or chain) using specially designed proof load test machines.

With the lift, the system is able to measure the tensile strength and load capacity of the material based on elongation under force. Hydraulic cylinders with high accuracy displays are used to provide a reliable measurement of the force applied.

A proof load test is a controlled, measured application of force over a specified time period to a given piece of rigging equipment. A mechanism using specially designed hydraulic cylinders with independent load cells provides an accurate reading of the force exerted on the material (rigging, wire or synthetic rope, chain, etc.). The test will ensure the material exceeds the maximum allowable working load (MAWL) on the material rating.

A working load limit is the maximum load that can be applied to a piece of lifting equipment without fear of the equipment failing. This is referred to in many different ways like maximum allowable working load (MAWL), safe working load (SWL), normal working load (NWL) and, of course, working load limit (WLL).

A working load limit is not simply calculated by finding the minimum breaking strength (MBS) of a piece of equipment. The WLL is a factor of the division of minimum breaking strength and the product’s safety factor (SF). A safety factor is decided on by engineers through compiled failure testing data and reliability of certain designs. The safety factor is meant to be a rating of how far beyond normal use conditions a piece of equipment can still safely perform.

To ensure any type of material (wire rope, synthetic rope, chain or rigging), is able to not only meet but exceed the MAWL (maximum allowable working load), a controlled test is performed.

This test uses hydraulic cylinders to create a specific force over a set period of time while testing the material used for the lift as to elongation and ability to retain shape under the force and time parameters.