Direct answer: A polyester lifting sling should be removed from service when it shows damage that the applicable standard defines as a removal condition — such as cuts or snags in the webbing, excessive abrasion, holes, heat or chemical damage, damaged or loose stitching, a deformed eye or fitting, or illegible marking. The decision is not a judgement of appearance but the application of defined criteria from EN 1492-1 (or EN 1492-2 for round slings) and ASME B30.9. Where damage approaches a criterion or the sling's history is unknown, the conservative course is to withdraw it for assessment by a competent person rather than to return it to service.

The Principle: Removal Criteria Are Defined, Not Improvised

The single most important idea in sling inspection is that removal is governed by criteria, not by opinion. Standards set out the conditions under which a sling must no longer be used, and a competent inspection applies them consistently. This matters because damage that looks minor can be significant, and damage that looks alarming can sometimes be within limits; only a defined criterion gives a repeatable, defensible answer. It also protects the inspector: following the standard turns a subjective call into a documented one.

Two of the most common failure conditions in service are mechanical damage (abrasion and cuts) and chemical or heat damage. Each has its own signs, and each should be checked on every inspection.

Abrasion: What Counts as Excessive

Abrasion is normal to a degree. A working polyester lifting sling will show surface fuzz, light polishing and a softening of the weave where it repeatedly contacts the load. The question is when wear becomes "excessive" in the sense the standard means. The signs to look for are a loss of material that changes the sling's cross-section, a localised thin patch, exposed internal structure, threads worn through to the point that the weave is visibly disrupted, and abrasive material such as grit or metal swarf embedded in the webbing. Wear that has progressed from surface fuzz to a measurable thinning of the body is the point at which the criterion is engaged.

Abrasion usually points to a location, not just a sling. If several slings wear at the same place, the cause is the contact point or the rigging, and replacing the sling without fixing the contact point simply repeats the wear. Treated and wear-resistant constructions, such as this wear-resistant 10 t endless polyester flat webbing sling, raise the baseline durability, but they still wear and are still inspected against the same criteria.

Cuts, Snags and Holes

Cuts are treated more severely than abrasion because they concentrate stress. A cut that severs or damages load-bearing yarns creates a local weakness, and the yarns beside it carry more, so a cut can grow under load even if it looks small. Signs include severed or frayed yarns, a clean slice at an edge, a snag where the weave has been pulled, and holes where material is missing. Damage at the eye and stitching is especially serious because those regions are already the highest-stress parts of the sling.

The direction of a cut matters less than its depth: a cut that reaches the structural layers is a removal condition, while a shallow surface mark that does not involve load-bearing yarns may be assessed. Because this distinction requires judgement, and because a wrong call at the eye can be catastrophic, the safe default is to withdraw any cut of uncertain depth for proper assessment.

Chemical and Heat Damage

Chemical and heat damage is the hardest to see, because the sling may look almost normal while having lost strength. Signs of chemical attack include discolouration, localised softening or stickiness, a change in stiffness, and embrittlement; as noted in our guidance on acid and alkaline exposure, alkalis are the particular concern for polyester. Heat damage shows as glazing, charring, melting, or a stiffened, brittle patch, and any contact above the fibre's rated temperature is a removal consideration regardless of appearance.

Both forms of damage share a dangerous property: they may reduce capacity without producing a visible defect. Where exposure is known to have occurred — a chemical splash, a hot contact — the sling should be withdrawn on the basis of the exposure, not on the basis that it still looks serviceable.

Damage Condition and Removal Decision

The table below groups the main damage types and the direction of the decision. It is an inspection aid for organising the check; the definitive criteria are those of the applicable standard, and any borderline case should go to a competent person.

Building a Removal-from-Service Regime

A reliable regime has four parts. First, a pre-use check: a quick look at the whole sling before each lift, focusing on the eye, edges and stitching. Second, a periodic inspection at a frequency matched to the duty and environment, carried out by a competent person. Third, a documented outcome: each sling is either returned to service or withdrawn, with the reason recorded. Fourth, a cause review: when a sling is withdrawn, identify what caused the damage so the rigging or the environment can be corrected. Without the fourth step, the same failure recurs on every replacement sling.

Labelling supports all four parts. A polyester lifting sling whose WLL, material and standard are not legible cannot be confirmed, and an unconfirmable sling is a removal condition in its own right. An anti-abrasion endless round sling with durable marking and a protective sleeve shows how construction choices can make the sling easier to inspect and longer-lasting in a demanding duty.

Frequently Asked Questions

Can a sling with a small cut still be used?

Only if the cut clearly does not involve load-bearing yarns, and even then the assessment should be conservative because cuts concentrate stress. Any cut of uncertain depth, especially at the eye or edge, should be withdrawn and assessed against the standard's criteria.

Is fading or discolouration a removal condition?

Not automatically, but it is a prompt for closer inspection. Discoloration may indicate UV exposure or chemical attack, both of which can reduce strength while the sling still looks usable, so the exposure history should be considered.

Who decides whether a sling should be removed?

The decision follows the criteria in the applicable standard and is applied by a competent person. The standard defines the conditions; the competent person determines whether they are met and records the outcome.

Should I repair a damaged sling instead of removing it?

No. Load-bearing stitching and webbing are engineered elements, and field repair cannot reliably restore their strength. A damaged sling should be removed from service, not patched.

Practical Guidance for Buyers and Rigging Engineers

• Inspect before every use and at a scheduled interval; focus on the eye, edges and stitching.
• Remove slings for excessive abrasion, structural cuts, holes, stitching damage, heat or chemical damage, or illegible marking.
• Treat any known over-exposure — heat above the limit, chemical contact, shock — as a removal consideration regardless of appearance.
• When a sling is withdrawn, fix the cause; review wear-resistant and protective options on the Polyester Flat Webbing Sling category page, and confirm markings and rating at purchase.
• Record every removal and its reason, and keep the inspection regime matched to the duty.

Removal from service is not a defeat; it is the control that keeps a sling system trustworthy. Applied consistently, defined criteria retire a polyester lifting sling at the right moment — not too early, wasting good equipment, and not too late, when the cost is measured in safety rather than in hardware.