Inspecting Slings, Chains and Lifting Accessories

Why is sling inspection handled separately from the crane?

An overhead crane is inspected once a year and the same crane is used for years. The polyester sling attached beneath it, however, can become unusable within a single shift because of a sharp edge, a welding burr or a drop of chemical. Sling inspection is therefore not a sub-item of crane inspection but a task with its own routine: visual check before use, discard decision, annual periodic inspection and inventory.

The legislation treats slings as lifting accessories. The Regulation on Health and Safety Requirements for the Use of Work Equipment contains three basic provisions:

• Annex I 3.2.2.1: Accessories used for lifting are marked to show the characteristics required for safe use.
• Annex II 3.1.4: Lifting accessories are selected according to the load to be lifted, the gripping points, the connecting components and the atmospheric conditions. Accessory assemblies that are not dismantled after use are clearly marked so that the user can know their characteristics.
• Annex II 3.1.5: Lifting accessories are stored in a way that ensures they are not damaged or degraded.

How do you read a polyester sling label?

Textile slings are manufactured to the TS EN 1492 series: flat webbing slings fall under 1492-1 and round slings under 1492-2. The label on the sling is its identity card. The colour of the label indicates the material:

• Blue label: polyester
• Green label: polyamide
• Brown label: polypropylene

The material matters, because each one resists chemicals differently. Polyester is relatively resistant to acids but is affected by alkalis; polyamide, on the other hand, is affected by acids. Choose the material of a sling to be used in a plating, galvanising or chemical plant according to the manufacturer's chemical resistance information. For the other risks of such plants, see our article on galvanising and electroplating.

The information that must appear on the label is: working load limit (WLL), material, length, manufacturer's name, traceability code, year of manufacture and standard number. The colour of the sling body indicates the load limit using standard colour coding: violet 1 tonne, green 2 tonnes, yellow 3 tonnes, grey 4 tonnes, red 5 tonnes, brown 6 tonnes, blue 8 tonnes, orange 10 tonnes and above. Colour is a quick indicator; the decision is always made on the value on the label.

The load limit on the label is for a straight (vertical) lift. As the slinging method changes, the load that can be carried also changes. The mode factors for a single sling in TS EN 1492-1 are as follows:

An example: a 3.2-tonne mould is to be lifted with a single sling in a basket hitch, with the angle between the legs between 45 and 60 degrees. At this angle the factor is 1.0; the load limit on the sling label must be at least 3.2 tonnes. A 3-tonne (yellow) sling is not enough; a 4-tonne (grey) sling is selected. If the same load could be lifted with the legs kept parallel, the factor would be 2.0 and a 2-tonne sling would be sufficient. This calculation is done before lifting, not while the load is in the air.

The most common mistake is using the label value unchanged in a choke hitch. When the angle exceeds 60 degrees, the force on the sling legs increases rapidly; no lift is made at this angle.

Chain slings and wire rope slings

Chain slings are more resistant to heat, abrasion and sharp edges than textile slings, which is why they are preferred in foundries, forging and heavy metalwork. Lifting chains are generally grade 8 or grade 10 alloy steel. A chain sling has an identification tag on its master link, showing the number of legs, the chain grade and the load limit according to leg angle. The capacity of a chain sling whose tag has been lost is not guessed.

Wire rope slings consist of rope with pressed or spliced end eyes. They are flexible and economical, but sensitive to crushing and sharp bending.

Whatever type of sling is used, a sharp corner on the load is the sling's greatest enemy. On sharp corners such as sheet bundles, profiles or mould edges, a textile sling can be cut within seconds under load. Corner protectors, protective sleeves or a suitable accessory are used at these points; protection is placed at every point where the sling touches an edge.

Practices prohibited for both types are: knotting a chain or shortening it with a bolt, passing a rope over a sharp edge without protection, repairing an accessory by welding and joining parts from unknown manufacturers.

Visual check before use

The person attaching the sling checks the following items before every use:

The hook safety latch is a small part, but it is the only barrier preventing the sling eye from slipping off the hook. A hook whose latch has been tied back, fixed with wire or broken is not used. For daily checks on the crane side, see our article on overhead crane safety.

Sling discard criteria

Discarding means permanently withdrawing a sling from use. The decision is based on the manufacturer's instructions and the current criteria of the relevant standard. Criteria commonly used in practice are:

1. Textile slings: A sling whose label has been lost or become illegible is discarded even if it looks sound; its capacity cannot be documented. Any cut reaching the load-bearing fibres and any heat or chemical damage is also a reason for discard.
2. Wire rope slings: More than 6 visible broken wires over a length of 6 times the rope diameter, or more than 14 over a length of 30 times the diameter (the criterion in TS EN 13414-2); crushing, birdcaging, knots and damage to the end termination.
3. Chain slings: Link diameter, averaged over two perpendicular measurements, falling below 90 per cent of the nominal diameter; visible stretching, bending, cracking or heat damage.
4. Hooks and accessories: Throat opening exceeding the dimension given by the manufacturer, bending or cracks.

Annual inspection records and sling inventory

In Table 2 of Annex III of the Work Equipment Regulation, "lifting accessories and carriers (slings, clamps, vacuum lifters, magnetic lifters and similar)" are a separate line. Unless the relevant standard specifies a shorter period, the maximum inspection interval is 1 year; the criteria include the TS EN 1492 series and TS EN 13155. Under Annex III 2.2.1.1, the static test coefficient for lifting accessories is 1.5 as a general rule. The inspection is carried out by an authorised person registered on EKİPNET (the Ministry's register of authorised inspection personnel); the contract is set up on ISG-KATİP (the Ministry's online OHS registration system) at least one day before the inspection. For the intervals, see our article on periodic inspection intervals.

For the annual inspection to be useful, each sling must be individually identifiable. A simple inventory consists of these columns:

• ID number (on the label or on a tag attached to the sling)
• Type, material, load limit and length
• Purchase date and manufacturer's certificate
• Department or crane where it is used
• Date and result of the last periodic inspection
• Discard date and reason

Some companies attach a tag in that period's colour to slings that have passed periodic inspection. This way, the question "has this sling been inspected?" can be answered on site at a glance.

Storage is also a requirement of Annex II 3.1.5. Do not leave slings on the floor, in oil and chemical spills or in the sun; a sling rack with hooks is the simplest solution. For suitable gloves against cuts and crushing when attaching and removing slings by hand, see our article on choosing work gloves.

At metal and machinery companies in Bursa and the surrounding provinces, the annual inspections of cranes and lifting accessories are planned through our periodic inspection service. You can track inspection dates with the OHS calendar, and for lifting operations on construction sites, read our article on tower crane safety.

Frequently Asked Questions

How often are slings periodically inspected?

Under Annex III of the Work Equipment Regulation, lifting accessories are inspected at least once a year unless the relevant standard specifies a shorter period. In addition, a visual check is carried out before every use.

Can a polyester sling with a missing label be used?

No. The label shows the sling's load limit and traceability. The capacity of a sling with an illegible label cannot be documented, and it is withdrawn from use.

Can a chain sling be knotted to shorten it?

No. A knot loads the chain links in the wrong direction and reduces capacity by an unknown amount. If shortening is needed, a suitable accessory such as the manufacturer's shortening hook is used.

Why is the hook safety latch so important?

The latch prevents the sling eye or ring from slipping off the hook. A hook with a missing, broken or tied-back latch can release the sling when the load swings; it is therefore not used.