Lifting Sling Testing Speed: Why It Matters and How to Control It Properly

 

How Fast Should You Test Lifting Slings?

When testing lifting slings, most people focus on test load and safety factor.
But there is another critical parameter that is often overlooked:

 Testing speed (loading rate).

The speed at which the load is applied can directly affect:

• Test accuracy
• Safety during testing
• Final test results
• Sling performance evaluation

In this article, we explain why testing speed matters, how it affects different sling types, and best practices for setting the correct speed during sling testing.

Why Testing Speed Matters for Lifting Slings

Testing speed refers to how fast the load is applied to the sling during proof or breaking tests.

If the loading speed is:

• Too fast → shock load, unstable readings, unsafe conditions
• Too slow → inefficient testing, possible creep effects on synthetic slings

Proper speed ensures:

• Stable load application
• Accurate test data
• Compliance with industry standards
• Protection for test operators and equipment

How to Set Speed on Testing Machines？

Most test machines allow speed control by:

• mm/min extension
• kN/s loading rate

Many horizontal tensile machines used for chain, wire rope, and lifting sling tests have adjustable speeds around 0.1–100 mm/min for load application and 200 mm/min for idle movement.

Conclusion

Testing speed is not just a machine setting — it is a key factor that determines:

• Test validity
• Safety level
• Compliance
• Product quality

By controlling loading speed properly, manufacturers and inspectors can ensure accurate, safe, and repeatable sling testing.