NFPA 1983 standard on elongation: At 10% of breaking strength, elongation must be no less than what percent and no more than what percent?

• A. No less than 5% and no more than 15%
• B. No less than 2% and no more than 8%
• C. No less than 1% and no more than 10%
• D. No less than 0.5% and no more than 5%

Answer: (C)

NFPA 1983 standards for life-safety rope specify how much a rope should stretch when loaded to a defined level. At a load equal to 10% of the rope’s breaking strength, the rope must lengthen by between 1% and 10% of its original length. This range ensures the rope isn’t too stiff at a modest load, which would make handling difficult and could create sharp shocks, while also preventing excessive stretch that would undermine control and performance during rescue operations. The 1% to 10% window is the balance NFPA sets to ensure predictable, reliable behavior under practical loading. Other ranges would either demand too little elongation or allow too much, which is why they don’t fit the standard.