Types of Rope

Rope Strength

The strength of a rope is rated by its working load limit and tensile strength (also called breaking strength). The tensile strength is determined in a lab and measures the amount of tension a new rope can take before breaking. The working load limit is a guideline for practical use of the rope. The working load limit tells you the maximum amount of weight the rope should support at any time.  

Although the working load limit is only 15  to 25 percent of its tensile strength, always determine the strength you need by working load limit and not tensile strength. Never exceed a rope’s or cord’s working load limit. 

• Light duty rope: Working load limit of up to 99 pounds. 
• Medium duty rope: Working load limit between 100 and 999 pounds. 
• Heavy duty rope: Working load limit of 1000 pounds or greater. 

Keep these factors in mind when determining the working load limit you need.

• The working load limit assumes that the load is static and not moving. 
• Tying a knot in the rope can reduce its working load limit by up to 50 percent.  
• Abrasion resistance is needed for ropes used with pulleys, winches or other devices that cause constant wear. 
• Dynamic, or moving, loads greatly reduce the ability of a rope to hold the load. 
• Creep is the amount synthetic fibers slowly stretch while handling a continuous load. Ropes never return to their original length once creep sets in. 

Safety Tip: Always consult the manufacturer’s instructions for handling heavy loads. Do not attempt to use ropes in situations in which a life will depend on them without proper training.