Sling Inspection and Maintenance: How to Prevent Sling Failure on the Jobsite Advantage Rigging

Picture a crew lining up a routine lift during a shutdown. The load is ready, the crane is positioned, and someone grabs a sling from the gang box. It looks fine at a glance. No obvious cuts, no broken hardware.

Halfway through the lift, the sling gives way.

Now the load is unstable, the area is shut down, and everyone is asking the same question: Why did it fail?

Situations like this happen more often than most crews admit. Slings are used every day, which makes it easy to treat them like simple tools instead of critical load-bearing equipment. Proper sling inspection and maintenance is what separates routine lifts from near-miss reports.

February is often when shops focus on preventive maintenance. It is a good time to look at lifting gear too. Slings do not last forever, and small issues compound quietly until they become big ones.

Here’s the short version:

• Always inspect slings before use
• Know the difference between Working Load Limit (WLL) and breaking strength
• Store and handle slings correctly to extend service life
• Remove damaged slings from service immediately

What Actually Fails vs What Just Looks Rough

A common misconception is that slings only fail when damage is obvious. In reality, many failures start inside the material where you cannot see them.

Examples of hidden damage include:

• Internal fiber breaks in synthetic web or roundslings
• Wire rope core damage beneath intact outer strands
• Heat degradation that weakens material without melting it
• Chemical exposure that reduces strength over time

Conversely, some slings may look worn but still be serviceable within manufacturer guidance. Dirt, superficial abrasion, or faded color alone does not automatically mean failure risk. What matters is loss of strength, not cosmetics.

Because the difference is not always visible, routine inspections by a trained person are critical.

Common Causes of Sling Damage

Most sling failures trace back to a handful of predictable causes.

Overloading
Exceeding the WLL is one of the fastest ways to cause immediate failure or permanent damage. Dynamic effects like sudden starts, stops, or snagging can push loads well beyond calculated weight.

Environmental Exposure
Heat, chemicals, moisture, and ultraviolet light all degrade materials differently. Synthetic slings are particularly sensitive to high temperatures and certain chemicals, while metal slings can suffer corrosion or hydrogen embrittlement.

Poor Storage
Slings tossed into a bin with chains, hooks, and sharp hardware develop cuts, kinks, and distortion. Long-term exposure to sunlight or moisture accelerates deterioration.

Improper Application
Using the wrong hitch, sharp edge contact without protection, or side loading hardware can reduce capacity dramatically and create localized stress.

Inspection Basics That Matter

Standards from OSHA and ASME generally require both frequent (pre-use) inspections and periodic documented inspections. The goal is to catch damage early before strength is compromised.

During inspection, look for:

• Cuts, fraying, or broken fibers
• Broken wires or bird-caging in wire rope
• Heat damage, melting, or glazing
• Chemical staining or brittleness
• Missing or unreadable identification tags
• Distortion in fittings or hardware
• Twists, kinks, or crushed sections

If the tag is missing or illegible, the sling’s capacity cannot be verified. In most cases, that alone is reason to remove it from service until properly identified.

Documentation also matters. Written inspection records help track deterioration trends and support safer replacement decisions.

When Replacement Is the Safer Choice

There is no universal lifespan for slings. Usage, environment, and loading conditions vary widely. However, certain signs strongly indicate that a sling should be retired.

Consider removal from service when you see:

• Significant cuts, tears, or broken wires
• Evidence of overloading or shock loading
• Stiffness, brittleness, or loss of flexibility
• Distorted or cracked hardware
• Severe corrosion or chemical damage
• Missing identification tag

Manufacturers often provide detailed retirement criteria for each sling type. When in doubt, conservative decisions prevent incidents.

The Rating That Matters: WLL vs Breaking Strength

Confusion between Working Load Limit and breaking strength leads to risky assumptions.

Working Load Limit (WLL)
The maximum load the sling is designed to lift under normal service conditions. This already includes a design factor for safety.

Breaking Strength
The load at which the sling will fail during testing. This is not a safe operating level and should never be used for lift planning.

Capacity also changes based on how the sling is used. Factors that reduce effective capacity include:

• Sling angle from horizontal
• Choker hitch configuration
• Uneven load distribution
• Edge contact
• Dynamic forces

A sling rated for one vertical lift may have substantially lower capacity in a basket or choker hitch at shallow angles.

Environmental Factors: Heat, Corrosion, and Wear

Conditions on industrial jobsites can degrade slings quickly.

Heat
High temperatures reduce the strength of synthetic materials and can alter the properties of metal components.

Corrosion
Acids, alkalis, and moisture can weaken both fibers and steel. Corrosion often begins in hidden areas.

Abrasion and Edge Contact
Repeated rubbing against rough surfaces removes material and concentrates stress. Edge protection is not optional when lifting sharp or abrasive loads.

Selecting a sling appropriate for the environment is just as important as selecting one for the load weight.

What Standards and Manufacturers Emphasize

Guidance from organizations such as OSHA and ASME generally focuses on three core principles:

• Use equipment within rated capacity
• Inspect regularly and remove damaged gear
• Maintain clear identification and records

They do not guarantee safety by themselves. Proper application and judgment on the jobsite still matter.

Common Mistakes Even Experienced Crews Make

Routine work can create complacency.

Frequent oversights include:

• Assuming a sling is safe because it “worked yesterday”
• Skipping inspections during time pressure
• Using whatever sling is closest instead of the correct one
• Ignoring angle reductions in capacity
• Leaving damaged gear in circulation

Small shortcuts accumulate until one lift exposes them.

Practical Checklist for Jobsite Use

Use this quick check before committing to a lift:

• Verify the sling type and capacity match the load and hitch
• Inspect the entire length, not just the visible section
• Confirm the identification tag is readable
• Check for cuts, broken wires, or stiffness
• Ensure hardware is not bent, cracked, or distorted
• Use edge protection where needed
• Confirm sling angles and load balance
• Remove questionable slings from service immediately
• Store unused slings clean, dry, and protected

Prevention takes minutes. Recovering from a failure can take days or longer.

When crews treat slings as critical equipment instead of consumables, both safety and efficiency improve.

Need a second set of eyes on your rigging?

Advantage Rigging helps customers choose, inspect, and replace lifting gear with clarity and confidence.

https://advantagerigging.com/
480-502-2225
info@advantagerigging.com

FAQ

Q1: How often should slings be inspected?
A1: Slings should receive a visual inspection before each use and periodic documented inspections by a qualified person based on usage and conditions.

Q2: Can a sling be used if the tag is missing?
A2: Without a readable tag, the sling’s capacity cannot be verified, so it should be removed from service until properly identified.

Q3: What reduces a sling’s lifting capacity?
A3: Factors include sling angle, hitch type, uneven loading, edge contact, and dynamic forces such as sudden movement.

Q4: Is breaking strength the same as safe lifting capacity?
A4: No. Breaking strength is the failure point during testing. Safe lifting is based on the Working Load Limit, which includes a safety margin.

Q5: Do synthetic slings handle heat well?
A5: Most synthetic slings lose strength at elevated temperatures and should only be used within manufacturer temperature limits.