Can Round Slings Be Used in High-Temperature Environments?

A steel mill needs to lift hot fabricated components near a furnace. A foundry requires a sling to handle castings that are still radiating heat. In both cases, the round sling selected will determine whether the lift proceeds safely—or fails catastrophically.

Lishenflex has been manufacturing synthetic round slings for decades, and our experience shows that temperature is one of the most critical—and most misunderstood—selection factors. A standard polyester round sling that performs flawlessly at ambient temperatures can lose its strength rapidly when exposed to heat above its rated limit.

1. Standard Round Sling Temperature Limits

The temperature ratings for round slings made of standard synthetic materials are defined by EN 1492-2, the European standard for roundslings made of man-made fibres .

1.1 Polyester (PES) and Polyamide (PA) Slings

Per EN 1492-2, polyester and polyamide round slings are suitable for use and storage in temperatures ranging from -40°C to 100°C (-40°F to 212°F) .

This 100°C limit applies to the load-bearing core. The protective sleeve may offer some thermal insulation, but the core itself must not exceed this threshold. CERTEX product specifications confirm this range for their polyester round slings: “Temperature range: Approx. -40° up to +100°C” .

1.2 Polypropylene (PP) Slings

Polypropylene round slings have a lower temperature ceiling: -40°C to 80°C (-40°F to 176°F) . This makes PP suitable for cold storage and general lifting, but not for any application involving heat.

1.3 What Happens Above the Limit

Exceeding the rated temperature limit causes permanent, irreversible damage to the load-bearing fibers. The Hanford Site Hoisting and Rigging Manual states that “The working temperature limits listed below shall not be exceeded without the manufacturer‘s written approval” .

ASME B30.9 lists melting, burn marks, charring, or other evidence of heat damage as conditions requiring immediate removal from service . Heat damage may not be immediately visible—the sling may become stiff or brittle before any surface charring appears.

2. High-Temperature Round Sling Options

For applications exceeding 100°C, specialized round slings are available.

2.1 Aramid-Based Round Slings

Aramid fibers—the same family as Kevlar®—offer dramatically higher temperature resistance than polyester. CERTEX offers Inferno® aramid round slings that “handle continuous temperatures up to +200 °C without any loss of strength” .

These slings are designed for:

• Steel mills—handling materials near furnaces

• Foundries—withstanding continuous heat exposure

• Power plants—heat-intensive maintenance operations

• Industrial production lines—lifting around hot components

Aramid slings remain lightweight and flexible, with the outer cover replaceable if damaged, extending service life .

2.2 High-Performance Round Slings

Slingmax SparkEater® round slings are engineered for temperatures up to 300°F (150°C) . They use high-temperature load-bearing core yarns protected by a specially engineered heat-resistant cover.

According to Slingmax, these slings are “ideal for steel mills, foundries, fabrication shops, power generation facilities, and other industrial environments involving hot materials or radiant heat” . They feature the Twin-Path® design with two independent load paths for redundancy, and the Check-Fast® Inspection System for visual overload indication .

2.3 Temperature Comparison Table

Source: EN 1492-2; CERTEX; Slingmax

Lishenflex’s lab data confirm that aramid slings retain over 90% of their breaking strength after prolonged exposure to 200°C, while standard polyester slings lose significant strength above 100°C.

3. Heat Damage: Inspection and Removal Criteria

Heat damage to round slings may not be immediately visible. Knowing what to look for is essential.

3.1 Visual Indicators

Per ASME B30.9 and the Hanford Site Hoisting and Rigging Manual, remove a round sling from service immediately when you observe :

• Melting—glazed or fused fibers

• Burn marks—discolored or scorched areas

• Charring—blackened, carbonized material

• Brittle or stiff areas—fibers that have lost flexibility

The Naval Facilities Engineering Command rejection criteria specifically lists “melting, burn marks, charring, or other evidence of heat damage” as grounds for immediate removal .

3.2 Hidden Heat Damage

Heat damage can occur without visible charring. A sling exposed to temperatures just above its rated limit may become stiff and brittle before any surface discoloration appears. The Naval Facilities guide warns inspectors to feel for internal bumps, bulges, or irregularities that may indicate core damage .

Critical note: If a round sling has been exposed to temperatures exceeding its rated limit—even briefly—remove it from service and have it inspected by a qualified person. The Hanford manual requires that temperature limits not be exceeded without manufacturer‘s written approval .

4. Protective Measures for Hot Environments

4.1 Use Appropriate Sling Material

Select aramid or high-performance round slings for any application where ambient or radiant heat exceeds 100°C. Do not use standard polyester slings in these environments.

4.2 Protective Sleeves and Covers

High-temperature round slings typically feature heat-resistant outer covers that protect the load-bearing core from radiant heat and abrasion. Slingmax SparkEater® uses a heat-resistant yellow cover; CERTEX Inferno® offers a replaceable outer sheath .

4.3 Inspection Frequency

In high-temperature environments, inspect round slings before every use and schedule periodic inspections more frequently than for normal service. ASME B30.9 requires monthly to quarterly periodic inspections for slings in severe service conditions.

5. Summary and Practical Recommendations

Round slings can be used in high-temperature environments—but not all round slings are suitable.

Key takeaways:

1. Standard polyester/nylon round slings are limited to 100°C per EN 1492-2

2. Polypropylene is limited to 80°C

3. Aramid round slings handle continuous temperatures up to 200°C

4. High-performance slings like SparkEater® reach 150°C (300°F)

5. Heat damage may be invisible—check for stiffness and brittleness, not just charring

6. Never exceed rated limits without manufacturer approval

Lishenflex manufactures round slings in standard polyester for general-purpose lifting, and can supply aramid and high-performance round slings for demanding high-temperature applications. Our products meet EN 1492-2 and ASME B30.9 standards, with clear temperature ratings and inspection guidance.

If you need assistance selecting the right round sling for your high-temperature application—or need help determining whether your current slings are suitable for the heat exposure in your facility—please send an email to sales@lishenflex.com, and our technical team will provide one-on-one support.