When to Retire a Lifting Slings: Visual Guide to Cuts, Abrasion, and Chemical Burns

A lifting sling is pulled from the storage rack. It looks fine—no obvious cuts, no visible wear. The rigging crew uses it for a routine lift. The sling fails. The load drops. The investigation reveals the cause: internal damage that wasn't visible during the pre-use check.

This scenario plays out in workshops and construction sites every year. According to industry data, a significant percentage of sling failures occur in slings that appeared serviceable to the naked eye . The Occupational Safety and Health Administration (OSHA) emphasizes that damaged slings must be removed from service, but the key question is: how do you know when damage is serious enough to retire a sling?

 

Lishenflex has been manufacturing synthetic lifting slings for over two decades, and our field data show that many riggers struggle to distinguish between cosmetic wear and damage that compromises safety. This guide provides a visual reference for the most common damage types and the specific retirement criteria defined by ASME B30.9 and OSHA regulations.

 

Cuts and Tears

Cuts and tears are among the most common and obvious damage types. However, not all cuts require immediate retirement—the depth, location, and severity determine whether the sling must be scrapped.

 

Retirement Criteria for Cuts

 

According to ASME B30.9, a sling must be removed from service when:

 

• Cuts, tears, or snags that expose the core yarns —once the protective outer layer is compromised, the load-bearing fibers are vulnerable

• Holes or tears in the webbing that penetrate through the full thickness

• Any cut that reduces the webbing width by a significant amount

 

Per OSHA's Guidance on Safe Sling Use, holes, tears, cuts, abrasive wear, or snags are listed among the conditions requiring immediate removal from service . The Canadian Centre for Occupational Health and Safety (CCOHS) adds that cuts, tears, snags, or holes in the sling body are visible signs of damage that warrant removal.

 

Visual identification:

 

• Minor surface cut —only superficial fibers affected; may be acceptable if no core exposed

• Deep cut —penetrates through multiple ply layers or exposes core fibers

• Edge cut —cut that reduces the effective width of the webbing at the edge

 

Critical note: Even a 10% edge cut can reduce sling capacity by 35% . This is why ASME B30.9 requires removal when any cut significantly compromises the sling's width or structure.

 

Abrasion and Wear

Abrasion occurs when slings are dragged across rough surfaces, pulled through narrow spaces, or used without corner protectors on sharp-edged loads. Unlike cuts, abrasion is often gradual and can be overlooked.

 

Retirement Criteria for Abrasion

 

Per ASME B30.9, a sling must be removed from service when:

 

• Excessive abrasive wear is present—wear that exposes core yarns or reduces the sling's cross-section significantly

• Surface abrasion has worn through the outer webbing to the load-bearing core

• Wear concentrated in a single area —localized abrasion is more dangerous than uniform surface wear

 

EN 1492-1 specifies that flat webbing slings must be removed when abrasive wear has damaged the webbing to the point where the original width is reduced or fibers are broken.

 

Visual identification:

 

• Light surface fuzzing —normal from use; acceptable

• Frayed edges —may be acceptable if minor, but inspect regularly

• Worn-through areas —exposing inner plies or core yarns; must be retired

• Powdered fiber between strands —indicates advanced abrasion

 

Lishenflex's lab data show that slings used without corner protectors can lose up to 50% of their strength in a single lift due to concentrated abrasion at the contact point. Corner protectors are not optional —they are essential for sling longevity.

 

Chemical Burns and Damage

Chemical damage can be one of the most dangerous types of sling damage because it is often invisible and can affect a sling's entire cross-section simultaneously.

 

Retirement Criteria for Chemical Damage

 

According to CCOHS, nylon slings are damaged by acids, while polyester slings are damaged by alkalis . When chemical damage occurs, the fiber structure is compromised, often without visible surface indication.

 

Per ASME B30.9, a sling must be removed from service when:

 

• Acid or caustic burns are present

• Discoloration indicating chemical exposure

• Brittle or stiff areas that indicate fiber degradation

 

The Liftex Slings safety guide warns that if a sling is exposed to acid or caustic chemicals and the fiber is damaged, the sling becomes stiff and brittle, resulting in a brown or black discoloration . These slings should be immediately removed from service.

 

Visual identification:

• Stiff or brittle feel —chemical damage makes fibers rigid

• Discoloration (brown, black, or unusual color) —often patchy or in areas of exposure

• Surface flaking or peeling —indicates advanced degradation

• Unexplained stiffness in areas not subject to wear

Heat Damage and Weld Splatter

Heat damage is particularly dangerous because it can weaken the sling without any visible surface change until the fibers become brittle.

 

Retirement Criteria for Heat Damage

 

Per ASME B30.9 and OSHA, a sling must be removed from service when:

 

• Evidence of heat damage —melting, charring, or blistering

• Weld splatter that has fused to the webbing

• Brittle or stiff areas that indicate thermal degradation

 

The CCOHS states that temperatures above 90°C (194°F) for polyester and nylon and above 80°C (176°F) for polypropylene can cause permanent damage . OSHA specifically lists melting, charring, or weld splatter on any portion of the sling as a condition for immediate removal from service.

 

Visual identification:

 

• Melted or fused fibers —the sling surface appears glazed or melted

• Charring or blackening —from direct flame or weld splatter

• Blistering —bubbles or bubbles on the sling surface

• Stiffness without charring —heat exposure below melting point can still cause degradation

 

UV Damage and Fading

Color fading is often the first visible indicator of UV degradation—and it is a sign that the sling may have already lost significant strength.

Retirement Criteria for UV Damage

 

Per ASME B30.9 and WAC 296-155-55825 , a sling must be removed from service when:

 

• Bleached or faded color is present

• Increased stiffness of the sling material

• Surface abrasion in areas not normally in contact with the load

• Brittle or stiff areas that indicate fiber degradation

 

The Rigging Institute warns that round slings with light-colored jackets can lose up to 40 percent of their ultimate strength over a six-month period of continuous UV exposure . According to the Liftex guide, UV damage can affect synthetic webbing strength in varying degrees from little to total degradation.

 

Visual identification:

 

• Faded color —the sling has lost its original color (often appearing bleached or white)

• Stiff or brittle feel —UV-damaged fibers become rigid

• Surface cracking or checking —fine cracks on the sling surface

 

Stitching and Splice Damage

Stitching is the most highly stressed component of a sling. The load-bearing splices and eyes carry the full load, and stitching damage is often the first indicator of imminent failure.

 

Retirement Criteria for Stitching Damage

 

Per ASME B30.9, a sling must be removed from service when:

 

• Broken or worn stitching in load-bearing splices

• Stitching pull-out —the stitching is separating from the webbing

• Cracking or severe wear at load-bearing seams

 

EN 1492-1 specifies that the stitching must be visually inspected for damage and must not have broken stitches in the load-bearing areas.

 

Visual identification:

 

• Broken stitches —one or more broken threads in the eye or splice area

• Worn stitching —the stitching has abraded and appears thin or worn

• Stitching pull-out —the stitching is separating from the sling body

• Uneven or distorted stitching —may indicate overload or improper manufacturing

 

Summary and Practical Recommendations

Knowing when to retire a lifting sling is essential for workplace safety. The key principle: when in doubt, scrap it out.

 

Immediate retirement checklist:

 

Practical actions to implement:

 

1. Conduct pre-use inspections—before every lift, check for visible damage

2. Document inspection findings—maintain records per ASME B30.9 requirements

3. Remove damaged slings immediately—never "save" a sling for later disposal

4. Destroy retired slings—cut or deface them to prevent accidental reuse

5. Train your team—ensure all riggers can identify damage types and retirement criteria

 

Lishenflex manufactures polyester lifting slings to EN 1492-1 and ASME B30.9 standards, with clear color-coded capacity markings and inspection training support. We emphasize that regular inspection and timely retirement are the foundation of lifting safety.

 

If you need assistance establishing a sling inspection and retirement program—or need help identifying damage types in your current inventory—please send an email to sales@lishenflex.com, and our technical team will provide one-on-one support.