ROPE CONSTRUCTION
Kernmantle - Kernmantle rope consists of twisted parallel fibers (the kern) surrounded by a tightly braided sheath (the mantle). The core fibers provide the majority (about 70%) of the rope’s strength. The sheath is tightly braided providing significantly higher abrasion resistance. There are two distinct types of kernmantle: dynamic and static. Dynamic is used for recreational climbing due to its high shock absorption capabilities. Static kernmantle has very low stretch and works well for industrial applications. Due to its construction, it remains round through descent devices and allows minimal twist on the rope. The properties of static kernmantle make it ideal for use as a life line or descent line.
3-Strand - 3-Strand ropes are an inexpensive rope option. They tend to have a lower breaking strength than double braid or kernmantle, so a larger diameter must be used to achieve the same strength. Due to their construction, 3-Strand ropes have a tendency to rotate under load and provide less abrasion resistance. These characteristics make it a poor load line. With regard to safety and working at height, 3-Strand is most commonly used as a lifeline due to compliance with OSHA requirements and compatibility with 5/8” rope grabs.
Double Braid - Double braided rope is, as the name implies, a braided core surrounded by a braided sheath. The inner and outer braids are generally designed to share the load equally with very low elongation. Double braid rope remains round under tension, imparts no rotational force when loaded and has a soft hand. These characteristics make it ideal for use as a load rope.