There is no one rope perfect for every use. Will it be used for caving, rock climbing, urban rescue, window cleaning, water rescue or sports? Obviously all these activities have different needs. Before acquiring a new rope you must first determine your needs and then select the rope which is most appropriate for your needs.
Made by twisting together bundles of fibers. This construction has been in use since Neanderthal days. Laid ropes tend to untwist when suspending. All load bearing fibers appear at the surface a number of times through the length of a twisted rope. Any abrasion or surface damage has an immediate and direct effect on the rope’s strength. Laid ropes are very susceptible to abrasion due to their construction. They tend to be stretchy which can be a disadvantage in rescue applications and rappels. Laid or twisted ropes should be used in non‑critical applications such as crowd control.
This construction is often found in sport ropes intended for rock or ice climbing. They are very stretchy (35% to 45% at failure). This stretchiness is meant to absorb some of the energy generated in a fall, thereby lessening the forces that would be transmitted to the person who has fallen. During climbing or in any situation where a fall of greater than factor one might occur, a dynamic rope must be employed. Stretch can be a disadvantage in many common rope related activities. Rescue operations often involve lowering equipment or people, and the stretch in dynamic ropes may cause loss of control at critical times, increasing the danger to the people on the rope. Stretchiness may cause loss of control when lowering a litter, clearly a situation to be avoided. When ascending a dynamic rope, the climber must first pull out all the stretch before he leaves the ground, adding a considerable amount of non‑productive motion. Dynamic ropes are manufactured with a thin sheath which will wear out quickly. Most manufacturers recommend replacing dynamic ropes after stopping one fall of greater than factor one. UIAA ratings are merely the number of test falls a rope has supported without breaking. Do not assume that a fall rating of 5, 6, 7, or higher means you can safely fall that number of times. UIAA testing is done in a laboratory. The conditions in the field will not be the same as in a controlled lab test. If your intended use is strictly rock, ice climbing or mountaineering, a dynamic rope may be the only type you need.
This rope has a braided sheath (the mantle) over a core (the kern) made of parallel untwisted fibers. Static ropes have very low stretch (15% to 20% stretch at failure). The core bundles contribute most of the rope’s strength. The load bearing fibers are inside the rope where they are protected from abrasion by the tightly woven sheath. The core bundles are continuous in length and run parallel, which not only reduces stretch but also eliminates spin when suspended in air. Currently static kernmantle construction is the preferred rope for most rescue situations due to the better control inherent in this type of construction. For rappelling or ascending a fixed line or in rescue lowering and raising, a static kernmantle is the best choice. The qualities of low stretch, high abrasion resistance and no‑spin were designed into this type of rope for these uses. Static kernmantle ropes should not be employed as a dynamic belay line or as a safety line when the potential fall factor exceeds one. For these applications you should use a dynamic rope. For fall factors of one or less, a static kernmantle rope should be satisfactory assuming the user has an adequate harness and the entire system is properly rigged with good hardware, and the rope is protected from cutting and abrasion. Be aware that when a fall is stopped using static kernmantle rope, the stop will be much quicker than the dynamic rope; and that the forces transmitted to the climber will be higher. The stop may not be as soft as it would be on a dynamic rope.
This is really two separate ropes in one. The core, which is a single braid, is overbraided with a second sleeve. This construction allows very high strength, maximum flexibility, low stretch, spliceable, and will not twist under load. It allows the use of many different options of various fibers in order to engineer a rope best suited to a particular application. This construction entirely shields one of the two rope elements from abrasion.
CAUTION: In situations as outlined above it is important to remember that the entire system is only as strong as the weakest link. Even with the strongest rope a system can fail at an anchor, carabiner, knot, seat harness or other points. Always carefully inspect every component in a system that will support a life. Don’t tempt the hand of fate.
Nylon is the most common rope fiber in sport and rescue ropes. “Perlon” is not another word for kernmantle as many people think. It is a European name for type 6 nylon. The first kernmantle ropes were made in Europe of Perlon fibers. As a result many people started calling all kernmantle ropes perlon. Nylon is manufactured in two different types: type 6 and type 6,6. Ropes made of type 6,6 will stand up to abrasion and wear slightly better than will equal ropes made of type 6. New dry nylon is about 10% stronger than polyester, but nylon can lose 10‑15% of its strength when wet. Nylon can absorb approximately 15,000 pounds of force per pound of dry rope, so nylon can cope with about twice the shock loading that polyester can, wet or dry. Nylon is a very inert material, and most chemicals do not have any adverse effects on it. Some acids will degrade nylon ropes, so avoid exposing it to any acids.
Polyester is a strong rope with low stretch and has excellent resistance to ultraviolet degradation from sunlight exposure. Holds knots well and has a firm construction for excellent abrasion resistance. Its good dielectric properties make it an excellent rope for use in many electrical/utility applications. Wet strength is 100% of dry strength, but it does not float. Polyester will melt at approximately 500°F(260°C). Use anywhere a high-strength low-stretch line is needed.
Polypropylene and polyethylene fibers are used in ropes for use in and around water where a floating rope is desirable. They also are impervious to acids and will not conduct electricity when dry. Polypropylene will melt at around 270 degrees Fahrenheit(132C) and polyethylene will melt at approximately 225 degrees Fahrenheit(107C), clearly too low for most rescue applications. The polyolefins have a very low resistance to abrasion, and do wear out very quickly. Polyolefin fibers are made in monofilament and multifilament versions. The monofilaments are larger in diameter, stiffer and more brittle than are multifilament fibers. Multifilament fibers are much smaller in diameter which makes a soft supple rope when compared to monofilaments. Other than in water rescue ropes, the polyolefin family is not a good choice for rescue ropes.
A fall factor is a number which expresses the maximum distance a load can fall on a given length of rope. To compute the fall factor divide the distance a load attached to the rope could fall by the length of rope between the anchor and the load. The accompanying illustration should help to clarify this point. In the example on the left, the person is standing on the same ledge as the rope is anchored to. Obviously he can only fall the length of the rope. This is a fall factor of one. The total length of the rope does not affect the outcome. A ten foot fall on a ten foot length will always compute out to one. The same is true whether the length is 10, 100 or 1000 feet. The illustration in the middle shows the anchor above the load. In this situation the fall factor will be less than one. For example assume the rope is 100 feet long and it is anchored 30 feet above the load. If the load is dropped it will fall 70 feet on a 100 foot length of rope, and in this case the fall factor would be less than one (.7 to be exact). In the illustration on the right the load is the full length of the rope above the anchor. If the load is dropped it will fall twice the length of the rope. This extreme fall computes out to a fall factor of 2. Use a dynamic kernmantle rope when the potential fall factor is greater than one. This type of potential is common in rock, ice and mountain climbing. When the potential fall factor is less than one, it is proper to use a static kernmantle rope. Factors of one or less are common when rappelling or in most rescue situations. Always strive to avoid shock loading any rope. Shock loads are capable of triggering catastrophic failures even in new rope.
UIAA testing is performed on dynamic ropes only. It is not applied to static ropes as this type of rope is not intended to absorb the energies developed in falls of greater than factor 1. In the UIAA drop test, a piece of dynamic rope 2.8m(9’, 2 1/4”) in length must hold a weight of 80kg(176 lbs.)(single rope) or 55kg(121 lbs.)(double ropes) dropped from a height of 5m(16’, 4 7/8”). The rope runs over a deflection edge with a diameter of 10mm(3/8 inch) which is approximately the diameter of a carabiner. The current UIAA standard requires that a rope should sustain at least five drops without breaking. The UIAA drop test has a fall factor of 1.78.
UIAA Test Procedure For Dynamic Ropes
FP ‑ Fixed point with carabiner
DE ‑ Deflection edge (10mm diameter)
W ‑ Drop weight of 80kg (single rope) 55kg (double rope)
LD ‑ Absorbing rope length ‑ 0.30m
LC ‑ Free rope length ‑ 2.5m
NO ONE ROPE SIZE OR STRENGTH WILL BE PERFECT FOR EVERY NEED. Rope strength is the more important of the two. Strength is usually expressed as tensile strength at break. There are as many ways to measure and describe rope strength as there are manufacturers of rope. In testing many factors come into play, any of which can move scores up or down. The rate at which the pull is applied, the temperature, the diameter of the mandrel, along with other factors can change test results. Descriptions can be just as bad. Maximum, average and minimum all are terms used to describe tensile strength. Obviously you can not compare one manufacturer’s maximum strength to another’s minimum strength. And there are manufacturers who only list a nebulous safe working load, not a tensile strength at all.
All test figures listed in this catalog are minimum. The minimum strength is the only one that counts when a life will hang on the rope. Ropes are tested according to Federal Standard 191A Method 6106. The NFPA also endorses the use of this standard. The testing of ropes is performed by an independent certified testing laboratory. Keep in mind that a laboratory test which is repeatable any time anywhere can not accurately reflect the conditions in the field. The actual performance in the field may not measure up to laboratory standards. A laboratory test does not take into account things such as knots or building edges. Ropes in the field are definitely affected by these and other factors.
Before selecting a rope you should first determine the greatest working load you will expect the rope to support in its lifetime. Will it be a rappel line for one person, a lowering line for two people with a litter and equipment, or a highline in a long tyrolean traverse? If your load was 300 pounds would you use a rope that is 300 pounds strong? Of course not. You would use a rope which is a number of times stronger than the load. This extra margin is called a safe working load or the safety factor. This is most often expressed as a ratio. The higher the ratio the greater the safety margin. For lifting non‑critical loads such as equipment, a ratio of 7:1 is adequate. For live or critical loads, the NFPA recommends a more conservative ratio of 15:1.
The current NFPA standard for one man ropes is as follows: safe working load 300 lbs.(136kg), minimum tensile strength 4500 lbs.(2041kg), minimum diameter 3/8”(10mm), maximum 1/2”(12.5mm). NFPA standards for two man ropes are: safe working load 600 lbs.(272kg), minimum strength 9000 lbs.(4082kg), minimum diameter 1/2”(12.5mm), maximum 5/8”(16mm). OSHA standards are a bit harder to nail down. The only recurring requirement we can find is a tensile strength of 5400 lbs.(2449kg) for a life line.
NFPA labeling is available on
All ropes can be cut to any length desired. Special lengths longer than standard 600 feet(183m) are available upon request.
Custom colors are also available on some ropes. Ropes can be custom braided to your specifications.
We stock ropes made by New England Ropes, Sterling Rope
Company, and PMI. Ropes made by Blue Water and
Accessory cords are scaled down kernmantle rope. Diameters smaller than 5/16”(8mm) are accessory cords, larger sizes are rope. A single accessory cord should not be used in a life supporting situation. Do not use static accessory cord for climbing, rappelling or rescue. Accepted uses for accessory cords include lashing, securing, hauling packs, equipment slings, runners, hammer or ice axe loops and for other non‑critical applications.
Exceptions to this rule are ascending systems and hauling systems utilizing knots. However, in these cases, the live or critical load must be supported by a redundancy in the system that will protect the load should a single accessory cord sling fail. Most authorities recommend that the climber be attached to the standing line by three or more points when ascending.
Static accessory cord, braid on braid cord, or twisted cords may be used for Prusik loops. Make absolutely sure that whichever type is used is strong enough for the intended load and that it is small enough in diameter (relative to the standing line) and will have enough friction to grab the standing line effectively. As a general rule, the Prusik loop material diameter should be approximately 60% to 80% of the standing line diameter. If the diameter is too small the hitch will tend to be tight, making it difficult to move upward. On the other hand, if the diameter is too large, the hitch will not tighten up enough to grip the standing line.
In life supporting applications such as rescue, many authorities recommend the use of two tandem triple wrap Prusik hitches.
This generally is the same as for ropes (See Our Rope Care Page) .Be especially vigilant when inspecting accessory cords. Due to their compact design and small diameters, accessory cords tend to wear out much quicker than ropes. Inspect Prusik slings religiously! Prusik hitches under heavy loading can slip. The resulting frictional heating can glaze or melt the sheath. Keep a sharp eye for this type of damage.