Carabiner

This article is about the safety device. For the weapon, see carbine. For the cavalry soldier, see Carabinier.
Clockwise from top left: D-shaped wire gate, D-shaped straight gate, Oval straight gate, Pear-shaped auto-locker, D-shaped screw-locker. Center is a standard carabiner rating.

A carabiner (/kærəˈbnər/) or karabiner is a metal loop with a spring-loaded gate[1] used to quickly and reversibly connect components, most notably in safety-critical systems. The word is a shortened form of Karabinerhaken, a German phrase for a "spring hook"[2] used by a carbine rifleman, or carabinier, to attach items to a belt or bandolier.

The carabiner has been improved several times over the decades, making it more lightweight, reliable and durable.

Use

Carabiners are widely used in rope-intensive activities such as climbing, arboriculture, caving, sailing, hot air ballooning, rope rescue, construction, industrial rope work, window cleaning, whitewater rescue and acrobatics. They are predominantly made from both steel and aluminium. Those used in sports tend to be of a lighter weight than those used in commercial applications and rope rescue. Often referred to as carabiner-style, carabiner keyrings and other light-use clips of similar style and design have also become popular. Most are stamped with a "Not For Climbing" or similar warning due to a common lack of load-testing and safety standards in manufacturing. While from an etymological perspective any metal attaching link with a spring gate is technically a carabiner, the strict usage among the climbing community specifically refers only to those devices manufactured and tested for load-bearing in safety-critical systems like rock and mountain climbing.

Carabiners on hot air balloons are used to connect the envelope to the basket and are rated at 2.5 tonne, 3 tonne or 4 tonne.[3]

Physical properties

Shape

Carabiners come in four characteristic shapes:

  1. Oval: Symmetric. Most basic and utilitarian. Smooth regular curves are gentle on equipment and allow easy repositioning of loads. Their greatest disadvantage is that a load is shared equally on both the strong solid spine and the weaker gated axis.
  2. D: Asymmetric shape transfers the majority of the load onto the spine, the carabiner's strongest axis.
  3. Offset-D: Variant of a D with a greater asymmetry, allowing for a wider gate opening.
  4. Pear/HMS: Specialized oversized offset-D's used in belaying. These are usually the heaviest carabiners.

Locking mechanisms

There are three broad categories of carabiner: auto locking, manual locking, and non-locking.

Non-locking

Non-locking carabiners (or snap-links)[4] have a sprung swinging gate that accepts a rope, webbing sling, or other hardware. Rock climbers frequently connect two non-locking carabiners with a short length of nylon web to create a quickdraw.

Three gate types are common:

  1. Straight gate: The most utilitarian, and hence most popular.
  2. Wire gate: The lightest type, with a strength roughly equal to the others, allowing more to be carried for a given weight. Wire gates are less prone to icing up than solid gates, an advantage in Alpine mountaineering and ice climbing. The reduced gate mass makes their wire bales less prone to 'gate flutter,' a dangerous condition created by irregular impact forces generated by the climbing rope or contact with hard surfaces in a fall which momentarily opens the gate (and both lowers the breaking strength of the carabiner when open and potentially allows the rope to escape).


Locking

Locking carabiners have the same general shape as non-locking carabiners but have an additional mechanism securing the gate. These mechanisms may be either threaded sleeves ("screw-lock"), spring-loaded sleeves ("twist-lock"), magnetic levers ("Magnetron") or double-gates ("Twin-Gate").

Certification

Europe

Carabiners are marked on the side with single letters showing their intended area of use, for example, K (via ferrata), B (base), and H (for belaying with an Italian or Munter hitch).

United States

American National Standards Institute/American Society of Safety Engineers standard ANSI Z359.1-2007 Safety Requirement for Personal Fall Arrest Systems, Subsystems and Components, section 3.2.1.4 (for snap hooks and carabiners) is a voluntary consensus standard. This standard requires that all connectors/ carabiners support a minimum breaking strength (MBS) of 5,000 lbf (22 kN) and feature an auto-locking gate mechanism which supports a minimum breaking strength (MBS) of 3,600 lbf (16 kN).

See also

References

  1. "Climbing Dictionary & Glossary". MountainDays.net. Retrieved 2006-12-05.
  2. "Online Etymology Dictionary". etymonline.com.
  3. "Cameron Balloons Maintenance Manual (refer to section 6.6.4)". Retrieved 2015-03-28.
  4. "Climber's Club Journal" (PDF). Climber's Club. Retrieved 24 April 2005.
  5. "Grivel Mega K6g Twingate". rockandice.com.
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