Contents
Overview
Types of lifting slings and how to choose one
The main types of lifting slings are chain, wire rope, flat webbing and round slings. Chain and wire rope are steel, and chain or steel-cored rope can work above a textile sling’s temperature limit. Webbing and round slings, made from man-made fibre, are the lightest, and LEEA’s code says they are likely to be best for a polished load.
Pick the material to suit the load and the conditions around the lift, then pick the number of legs to suit the load’s lifting points. The code of practice from the Lifting Equipment Engineers Association (LEEA) also covers fibre rope slings, which this guide leaves out.
In short
- Polyester and polyamide slings stop at 100 °C, while grade 8 chain keeps its full rating up to 200 °C.
- In acid, LEEA advises against chain and wire rope, and the right textile depends on the chemical.
- Match the legs to the lifting points. Under the uniform load method, a four-leg sling is rated no higher than a three-leg sling of the same size and grade.
- In a choke hitch, any of the four types may lift only 0.8 of its marked rating.
On a contract lift, our own appointed person plans the lift and writes the lift plan.
Chain
Chain slings
A chain sling is alloy steel chain with forged fittings: a master link at the top, which goes on the crane hook, and a hook or link on the end of each leg. Chain is graded by strength, and the British Standard for chain slings, BS EN 818-4, covers grade 8.
Chain resists abrasion better than any other sling material and is the likely choice near a furnace or in other hot surroundings. Its legs can be shortened on the job with a shortening clutch, a fitting that holds the chain at the length needed and is preferred to other shortening methods.
Heat and acid limits
Chain is heavy to handle, and even chain has a temperature limit. Grade 8 keeps its full rating up to 200 °C, is derated between 200 °C and 400 °C, and is not recommended above 400 °C. LEEA’s code says chain of grade 8 and above, and grades S and T, should not be used in acid or acid fumes, because hydrogen embrittlement can make the steel crack and fail suddenly.
Wire rope
Wire rope slings
A wire rope sling is steel wire rope with an eye at each end. The eye is formed by splicing the rope back into itself or by pressing a metal sleeve, called a ferrule, over the joint, as BS EN 13414-1 describes.
How much heat it takes depends on how it is made. A rope with a fibre core is limited to 100 °C, and a steel-cored rope with aluminium ferrules to 150 °C. With a steel core and steel ferrules or spliced eyes, the sling can be used up to 400 °C, with its rating reduced in steps above 100 °C. Aluminium can spark, so its use is restricted in some areas classed as explosive atmospheres.
Fixed length and broken wires
A wire rope sling cannot be adjusted. LEEA’s code says no attempt should be made to shorten it by knotting or any other means, so order the length the job needs. Wire rope is not recommended in acidic conditions, and broken wires can injure the hands of the people handling it.
Textile
Flat webbing and round slings
Textile slings are the lightest for a given lifting capacity, and webbing or a round sling is the likely choice for a polished or delicate load.
Flat webbing slings
A webbing sling is a flat woven strap, 25 mm to 450 mm wide, with a soft eye or a metal fitting at each end. Single-leg slings are the popular choice, as they can be used alone or coupled into multi-leg sets. Duplex slings, with two or more layers, are stiffer than single-ply webbing.
Round slings
A round sling is an endless loop: a core of continuous yarn inside a woven cover that carries no load and only protects the core. Round slings have replaced endless webbing slings for everyday use.
The core cannot be seen, so a check before use relies on the cover. If the cover is undamaged and nothing else points to a problem, the core can be treated as sound. A sling with any core showing should be withdrawn from use and referred to a competent person, who has the training and experience to examine it properly.
Temperature and chemical limits
Textile slings are not for a hot load, and each fibre reacts differently to chemicals. The limits in LEEA’s code are the same for round slings as for webbing.
| Fibre | Temperature | Chemicals |
|---|---|---|
| Polyester | -40 to 100 °C | Resists moderate acids, damaged by alkalis |
| Polyamide (nylon) | -40 to 100 °C | Unaffected by alkalis, attacked by moderate acids. Can lose around 15% of its strength when wet |
| Polypropylene | -40 to 80 °C | Little affected by acids or alkalis, damaged by some solvents and paints |
Abrasion wears textile faster than steel. Where a sling could rub or bear on an edge, use a protective sleeve or packing. Textile slings are colour coded, and the colours and the label are explained in our guide to lifting accessory standards.
Choosing
Choosing the right type of sling
Start with the load and the conditions, then pick the material. One of LEEA’s basic principles for slinging is that neither the sling nor the load should damage the other.
Here is how the four types compare. The limits come from LEEA’s code, and each is linked in the sections above.
| Type | Heat limit | Points to know |
|---|---|---|
| Chain (grade 8) | Full rating to 200 °C, reduced from 200 to 400 °C | Best abrasion resistance, and likely to last longer on sharp edges. Legs can be shortened with a clutch. Should not be used in acid. |
| Wire rope | 100 °C with a fibre core, 150 °C with a steel core and aluminium ferrules. Up to 400 °C with a steel core and steel ferrules or spliced eyes, derated above 100 °C | Fixed length. Broken wires can injure hands. Not recommended in acid. |
| Flat webbing | 100 °C in polyester or polyamide, 80 °C in polypropylene | Lightest for its capacity and kind to a polished load. Wears faster than steel. Chemical resistance depends on the fibre. |
| Round sling | As webbing | As webbing. Withdraw it if any core shows. |
Every sling needs a sharp edge protected, chain included. In corrosive conditions, LEEA says specialist advice should always be sought.
Edges and packing
Bending a sling round a corner weakens it. Rounding off the edge stops it cutting the sling but does not stop the loss of strength. LEEA’s example is a wire rope bent round a radius of four times its own diameter, which loses about a quarter of its strength. Packing such as timber or rubber has to stay in place for the whole lift.
Follow the sling’s marking and what its maker’s instructions say. In Great Britain, the Lifting Operations and Lifting Equipment Regulations 1998 (LOLER) require a competent person to plan every lift, and BS 7121-1 names the appointed person for that role on a crane lift.
Legs
Single-leg and multi-leg slings
The number of legs follows the load’s lifting points. LEEA recommends a single-leg sling for a load with one lifting point, such as the eyebolt on an electric motor.
- Two-leg slings have both legs joined at the top by one link and are marked as one assembly. Two identical single slings can be joined with a shackle instead, with the legs placed symmetrically and each no more than 45 degrees from vertical.
- Three-leg slings suit round or irregular loads where the legs can be spaced evenly.
- Four-leg slings are mainly for square or rectangular loads with a lifting point at each corner.
Under the uniform load method used in the standards, a four-leg sling is rated no higher than a three-leg sling of the same size and grade, because the load might be taken by only three legs. Using fewer legs also cuts the rating: load a four-leg chain sling used on two legs to no more than half its marked load.
Leg angle matters as well. Under the same method the marked rating applies with the legs no more than 45 degrees off vertical, a lower rating applies between 45 and 60 degrees, and LEEA’s code gives no rating beyond 60 degrees. How the marked figure relates to what you can lift is covered in our guide to SWL and WLL. Our guide to sling angles explains how leg angle changes the load in each leg.
Hitches
Ways of slinging a load
Each way of attaching a sling to a load is called a hitch. A hitch changes how much the sling can lift, so each one has a mode factor: a number you multiply the rating marked on the sling by to find the most it may lift that way.
A straight lift hangs the sling from the hook to a single lifting point, and the sling keeps the full marked rating, a factor of 1. A choke hitch wraps the sling round the load and back through itself, and a basket hitch passes it under the load with both ends on the hook.
For chain and wire rope slings, LEEA’s code gives 0.8 in a choke hitch. In a basket hitch with each part within 45° of vertical, the factor is 1.4. For chain, that figure applies only to a sling with a master link at each end and both links on the hook.
Webbing and round slings share those two factors. A textile sling in a basket hitch with its two parts parallel has a factor of 2. Endless webbing slings are not recommended in a choke hitch, because the webbing twists.
From our lifts
We check the label is there and readable, the last thorough examination is in date, and there’s no cut, burn, crushed fibre or damaged cover. A sling with no label is not used.
We fit wear sleeves to the slings where they touch sharp edges, and they have to stay in place as the load takes the strain.
We mainly use chain where a leg needs shortening to level an uneven load. It also suits heat, sharp castings, swarf and oil, while round slings go on painted or finished machines.
Peter Stephens, Managing Director
Questions
Common questions
What is a lifting sling?
A lifting sling connects a load to the hook of a crane or hoist. It is made of steel, as chain or wire rope, or of man-made fibre, as a flat strap or a round loop. In Great Britain, LOLER defines an accessory for lifting as equipment for attaching loads to machinery for lifting, which covers a sling.
How many types of lifting sling are there?
LEEA’s code of practice has chapters on five types of lifting sling: chain, wire rope, fibre rope, flat webbing and round slings. Chain and wire rope are steel, and the other three are textile. This guide compares the four types other than fibre rope.
What is the strongest type of lifting sling?
No one type is the strongest. Every type is made in a range of capacities, so the figure that counts is the working load limit marked on the sling, adjusted for the hitch and the leg angle. Chain and steel-cored wire rope cope with more heat, which is a separate question from capacity.
What are the common mistakes when using a sling?
Twisting or knotting a sling, and dragging it out from under a load, are two mistakes LEEA’s code rules out. A sling should not be used to drag a load either. Two more are going past the sling’s rated leg angle and leaving a sharp edge without packing, where it can cut the sling.
Do lifting slings need to be certified?
Yes. A new sling comes with a declaration of conformity, which HSE asks you to keep with the examination records. In Great Britain, LOLER then requires the safe working load to be marked on each sling, and a competent person must thoroughly examine it at set intervals. Our guide to LOLER inspections covers the intervals and the report.
What regulations apply to lifting slings?
In Great Britain, the two main sets of regulations for using lifting slings are LOLER and PUWER. LOLER covers lifting equipment and its accessories, from planning the lift to thorough examination. PUWER covers all work equipment, including whether it suits the job and how it is maintained. Northern Ireland has its own 1999 versions of both.
Get help
Choosing slings for a lift
Call us on 0800 008 6096 or email office@synergy-lifting.co.uk. Include photos showing the load’s surface and any lifting points, along with its weight, and we will tell you which slings suit it and how to attach them.
Our crane hire and contract lifting page covers lifts where we supply the crane and the rigging. For plant and production machinery, see machine movement.
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Send us the details and we will come back with a quote, usually the same day for a desktop survey.
Or call 0800 008 6096
