Which lifeline has less than 2% stretch at 300 pounds of force?

Which lifeline has less than 2% stretch at 300 pounds of force?

• A. KM III
• B. CMC lifeline
• C. Static-Pro Lifeline
• D. Tag Line

Answer: (C)

Stretch under load indicates whether a rope behaves as static or dynamic. For a rescue lifeline, staying close to its original length under load is crucial for predictable positioning and to limit shock on anchors. A static lifeline is engineered to elongate very little, typically less than 2% when subjected to a 300-pound load. The Static-Pro Lifeline is designed as a static lifeline, so it meets this low-stretch spec and remains essentially the same length under that force. In contrast, KM III is a dynamic rope intended to absorb energy by stretching, which means it would extend more than 2% at the same load. The CMC lifeline and tag line are not optimized for the ultra-low stretch required of a static rescue lifeline; they generally exhibit more elongation or are used for purposes other than a primary load-bearing lifeline.

Stretch under load indicates whether a rope behaves as static or dynamic. For a rescue lifeline, staying close to its original length under load is crucial for predictable positioning and to limit shock on anchors. A static lifeline is engineered to elongate very little, typically less than 2% when subjected to a 300-pound load. The Static-Pro Lifeline is designed as a static lifeline, so it meets this low-stretch spec and remains essentially the same length under that force.

In contrast, KM III is a dynamic rope intended to absorb energy by stretching, which means it would extend more than 2% at the same load. The CMC lifeline and tag line are not optimized for the ultra-low stretch required of a static rescue lifeline; they generally exhibit more elongation or are used for purposes other than a primary load-bearing lifeline.