Everything you need to know about chain slings

Wednesday, 30 September 2020

Anyone in the lifting industry is probably familiar with chain slings, and you may have been using them for years or even decades. There is a wide variety of options available in the market as well as a range of guides that offer assistance in working out which chain sling you should use. This article provides you with a broad range of information including an overview of the types of chain slings, things to consider before selecting or using your sling as well as our inspection, care and storage recommendations to ensure compliance and safety. If you ever have a question or uncertainty in regard to lifting equipment or a lifting method, always consult a professional, never guess – safety should never be compromised!

Types of chain slings

The configurations of chain slings are based on sling legs. Chain sling comes in a variety of options including 1, 2, 3 or 4 legs as well as lengths ranging from 1m to over 30m. There is also a range of components available (ranging from 8mm to 32mm), but choice of these will be heavily dependent on what and how you are lifting the load. The most commonly used chain assemblies are illustrated below, also illustrated are special assemblies that may be devised for lifting specific or unusually shaped loads.

To see Nobles range of pre-assembled chain slings for quick and easy purchasing, click here.

Sling selection

The following factors should be considered before choosing a chain sling.

  1. Load – mass

  2. Headroom

  3. Type of load – steel, shipping containers, timber, fabricated sections, vessels etc.

  4. Length of sling

  5. Method of slinging

  6. Environmental elements such as corrosion or heat.

For more information on these factors, read our Smarter Lifting article ‘How to choose the right sling’.

Inspection before use

The pre-use inspection for chain slings should take note of the following.

  1. Clean the sling before inspection.

  2. Ensure the sling is correctly tagged and certified.

  3. Every chain link should be individually inspected for any signs of wear, twisting, stretching, nicks, gouging, heat damage, chemical attack or excessive corrosion.

  4. Any worn links should be measured to determine the degree of wear, which should not exceed 10% in any plane.

  5. Upper and lower terminal links, hooks, etc. should be inspected for any signs of distortion, e.g. widening of any hook throat opening.

  6. Connecting links or chain connectors should be inspected for any signs of wear at their load-bearing points and for any excessive play of the load pin.

  7. Wear may be tolerated until the thickness of any worn section has been reduced by 10% of the nominal section in any plane.

  8. Chain links or fittings that have any defects should be clearly marked to indicate rejection and the sling should be withdrawn from service until properly repaired.

  9. Slings with damaged fittings may be repaired by replacing the fittings but the entire chain assembly must be proof load tested before being returned to service. Any damaged chain must be destroyed.

Care in use

Chain slings should always be used in line with good lifting and rigging practice and as per the manufacturer’s recommendations. Incorrect chain sling use could result in a dangerous situation that could cause property damage, serious injury or death.

  1. The operator should establish the weight of the load to be lifted as accurately as possible.

  2. Ensure that the crane or other lifting equipment and the lifting points are adequate to lift the load.

  3. Prepare the site where the load is to be landed in advance. Ensure that the sling is not trapped by the load in such a way that removal of the sling cannot be made by hand.

  4. Check compatibility of the chain sling to the crane hook and the lifting points on the load.

  5. Ensure the chain is free from twists and is protected from any sharp corners on the load.

  6. Ensure the load is evenly distributed on all sling legs. This can be facilitated through the use of shortening hooks.

  7. When using a choke hitch, the bite should be allowed to assume its own position.

  8. Commence the lift slowly, taking up the slack gradually.

  9. Care must be taken to ensure that the load remains stable throughout the lift.

  10. A trial lift should be made prior to the full lift operation. If the load is not balanced it should be lowered and the slings re-positioned.

  11. Sling hooks of a multi-leg sling should be positioned so that they face outward from the load.

Storage and handling

Chain slings should be kept on a properly designed rack in a clean, dry place. If you are going to store your slings for a prolonged period of time, lightly oil them before storage.

WARNING! Chain slings should not be used in acid solutions, exposed to acid fumes or other corrosive environments, and never heat or heat-treat slings.

Heat

As the temperature which a sling attains in-service increases, its strength decreases. Care must be taken to account for the maximum temperature that can be reached by the sling in service.

Temperature of sling

Strength of sling

Up to 200ºC

Nominal strength of rating

200ºC - 300ºC

90% of strength rating

300ºC - 400ºC

75% of strength rating

Over 400ºC

DO NOT USE

 

Note: The use of a sling within these temperature ranges does not imply any permanent reduction in strength when the sling is returned to normal temperatures. If slings are accidentally exposed to temperatures indicated in excess of the maximum permissible temperatures indicated above, they should be withdrawn from service and returned to Nobles for inspection, testing and/or repair or replacement.

Working Load Limit

Working Load Limit (WLL) is the maximum load that can be supported by a sling under general conditions of use. General conditions of use are equivalent to a group classification of crane mechanisms of M3 as specified in AS 1418.1.

Under other than general conditions of use (e.g. severe conditions or hazardous conditions involving safety of personnel), the WLL shall be derated to conform to the group classifications of crane mechanisms as specified in AS 1418.1 for conditions of use that apply.

Endless slings

The WLL of endless chain slings shall be not more than 1.5 times the WLL of the chain.

Non-vertically orientated leg of a sling

The WLL of a non-vertically orientated leg of a sling shall allow for its inclination to the vertical.

Adjustable slings

The WLL of adjustable chain slings shall be as follows:

  1. Where a special purpose hook (e.g. a shortening clutch) that fully supports the chain link and attains a 100% efficiency is used, the WLL shall be not more than the WLL of the chain to which it is attached.

  2. Where (i) above does not apply, the WLL shall be not more than 0.75 times the WLL of the chain to which it is attached.

Multi leg slings

The WLL of multi-leg slings shall be as follows:

  1. The WLL of a multi leg sling assembly with more than two legs shall not exceed that for the sling with only two of its legs used with an included angle of 60° between these two legs. That is, the WLL of multi leg sings comprising more than two legs shall be not more than the WLL of the sling used as a two-leg sling.

  2. Where a sling is not symmetrically loaded, the WLL shall be based on an included angle equal to twice the largest angle from the vertical.

  3. The WLL for a multi leg sling having an included angle of 60° between the legs is the maximum WLL for the sling and shall not be exceeded, even where the included angle between the legs is less than 60°.

  4. Under no circumstances shall the included angle between the legs of a multi leg sling be allowed to exceed 120°.

Adjusting slings using shortening clutches

Nobles can incorporate shortening clutches into all sling assemblies rendering them adjustable. Shortening clutches in multi-leg slings will adjust the leg length but care must be taken to ensure that no one leg is overloaded as a result. Bear in mind that if the legs are not equally disposed about vertical, the leg making the smallest angle to the vertical will carry a larger share of the load.

Shortening clutches are the preferred devices for adjusting leg length as they maintain the correct ‘in line loading’ of the chain so that the rating is not affected. Some grab hooks that lock onto a link of the chain for this purpose require a 25% deration. Cradle grab hooks, which fully support the chain link, do not require a deration.

WARNING! Shortening clutches MUST be used correctly with the load bearing chain always leading out from the bottom of the clutch.

Headroom and special slinging methods

Use of lifting beams or spreader beams assist in overcoming headroom problems. Nobles engineering team can purpose build beams to comply with all relevant standards and regulations. We also have a range of premade material handling equipment that is available for immediate dispatch. Any special method of use should be approved and tested in the way it is to be used, that is why we have our team of lifting specialists are available for consultation to ensure you get the right equipment for your lift.

     

Nobles chain slings

NOBLE10™ chain slings are manufactured and extensively tested by Nobles’ specialist lifting and rigging engineers in Australia. You can rest assured knowing that NOBLE10™ meets the highest safety and quality standards, including Australian Standards AS3775, AS2321 and AS3776.

All chain slings manufactured by Nobles are fully proof tested to twice the WLL. Nobles maintain NATA accredited testing laboratories with facilities to carry out proof and destruction type testing of chain and chain sling components.

For more information on Nobles range of chain slings and components check out the 'Lifting Slings & Components' section in our Riggers Handbook. If you have any queries about using your chain sling, please call our sales team on 1300 711 559. If you would like to have you chain sling inspected, repaired, tested or certified, please contact our technical services team on techservices@nobles.com.au.

BACK TO LIST

 

Share this article: 

Facebook Linked In Tweet