Carabiner

Lore & Background

Carabiners are predominantly made from both steel and aluminium, with those used in sports tending to be lighter than those for commercial applications and rope rescue. They come in four characteristic shapes: oval, D, offset-D, and pear/HMS. Oval carabiners are symmetric and gentle on equipment but share load equally on spine and gate. D-shaped carabiners transfer most load to the strong spine. Offset-D variants allow a wider gate opening. Pear/HMS carabiners are larger and used for belaying with a Munter hitch or certain belay devices, and are typically the heaviest.

Reader's Guide

Carabiners fall into three broad locking categories: non-locking, manual locking, and auto-locking. Non-locking carabiners have a sprung swinging gate and include solid gate and wire gate designs. Wire gate carabiners are lighter and less prone to icing and gate flutter. Locking carabiners add a mechanism to prevent unintentional opening, such as screw-lock, twist-lock, magnetic levers, or double-gate designs. In Europe, climbing carabiners must conform to EN 12275:1998 with a minimum breaking strength of 20 kN with the gate closed and 7 kN open. Industrial carabiners must comply with EN 362:2004. In the United States, climbing carabiners follow ASTM F1774, requiring 20 kN on the long axis and 7 kN on the short axis. Rescue carabiners are addressed in ASTM F1956, with light-use and heavy-duty classifications. Carabiners used on hot-air balloons are rated at 2.5, 3, or 4 tonnes, while those for diver's umbilicals are rated for a safe working load of 5 kN or more.

Did You Know?

• The word carabiner comes from the German Karabinerhaken, meaning 'carbine hook,' used by carabiniers to attach carbines to belts.
• Carabiners used in climbing are typically rated to 20 kN or more, equivalent to over 2000 kilograms of force.
• Wire gate carabiners are less prone to 'gate flutter' than solid gate designs, a dangerous condition during falls.