NFPA 1983 elongation standard specifies elongation measured at 10% of breaking strength. What is the minimum elongation?

• A. 10%
• B. 5%
• C. 1%
• D. 0.1%

Answer: (C)

NFPA 1983 uses elongation measured at a defined fraction of breaking strength to describe how much a rope will stretch under a light-to-moderate load, which matters for energy absorption in a live-load scenario. The standard requires that at 10% of the rope’s breaking strength, the rope lengthens by at least 1% of its original length. In practical terms, this minimum elongation ensures the rope isn’t too stiff, providing some stretch to damp peak forces and improve safety in dynamic loading. If the rope stretched less than 1% at that load, it would be excessively stiff; if it stretched far more, system behavior could become unpredictable. The 1% figure is the established minimum, not a higher threshold.