Which type of general use life safety rope stretches 1-10% at 10% of its minimum breaking strength?

• A. Static
• B. Kernmantle
• C. Sheath
• D. Dynamic

Answer: (A)

Low stretch under load is the defining feature of static life safety rope. When you load a static rope to about 10% of its minimum breaking strength, it should elongate only a small amount—typically around a percent or two, sometimes a bit more but usually well within single-digit percentages. This predictable, minimal give is exactly why static ropes are favored for fixed lines, hauling, and anchor work where you need the rope length to stay reliable and not extend significantly as it bears load.

Dynamic ropes are designed to stretch much more to absorb energy during a fall, so they would not fit the 1-10% elongation at 10% of MBS description. Kernmantle describes a construction style (core plus sheath) used in many ropes, but it doesn’t specify how much the rope will stretch; the same construction can be found in both static and dynamic ropes. The sheath is simply the outer covering and doesn’t define elongation behavior.

Therefore, the option describing low elongation at that load matches static rope.