Which type of sling generally does not stretch at rated capacity but can stretch as much as 15% to 20% prior to failure?

• A. Nylon
• B. Chain
• C. Polyester
• D. Wire Rope

Answer: (B)

How a sling material deforms under load is what this question tests. Chain slings, made of steel, resist stretch under the rated capacity, so their length stays essentially constant during normal lifting. As the load rises toward failure, the links yield and deform, allowing the chain to elongate noticeably—often about 15% to 20%—before the chain breaks. This combination—minimal stretch at rated load with substantial elongation just before failure—fits chain slings best. Nylon and polyester slings are synthetic fibers that stretch more under load and can creep over time, so they don’t exhibit that same pre-failure elongation pattern. Wire rope has different stretch characteristics and generally does not show the same 15–20% pre-failure elongation as chain.