Carabiners and quickdraws: types, markings and strengths.

The standard and where it came from

A text written for the BMC in 2001 by Neville McMillan, which the UIAA publishes as its recommendation on UIAA 121, says the UIAA Safety Commission produced the first karabiner standard for climbing and mountaineering in 1965. That standard and its revisions became the basis of the European connector standard EN 12275, first published in 1998. The same year the UIAA aligned its own standard with EN 12275 and renamed it from "Karabiners" to "Connectors"; the BMC text says the two were then essentially the same.

The current editions are EN 12275:2013, as SATRA (a UIAA-accredited laboratory) summarises it, and UIAA 121 at version 4 (2018). The European Commission's PPE guidelines (5th edition, October 2025) list climbing karabiners among Category III equipment against falls from a height.

The standard uses the word "connector" so that new designs and items such as screw-closed quick links are covered alongside traditional karabiners. The BMC text traces the word karabiner to the German Karabinerhaken, a sprung hook for carrying a carbine, adopted by alpinists for clipping to pitons around 1900.

Connector classes and their minimum strengths

Each class has its own laboratory minimums. The figures below are SATRA's table of EN 12275:2013 minimum static strengths in kN. They are the values a sample must reach in the test to be certified, not a guide to loads in use.

SATRA notes that the gate-open requirement does not apply to classes B, H, A, T and X when the connector has an automatic gate-locking device, and that the class K minor-axis requirement applies even if the connector is also directional. Many connectors claim a higher major-axis rating than the minimum, and the maker must show for certification that the higher figure is achieved.

The standard's laboratory gate tests, as SATRA summarises them, include the forces to close and latch the gate, the gate still opening and closing fully under an 800 N load, and limits on how far the gate separates under face and side loads.

Reading the markings

According to the BMC text, EN 12275 requires three strengths to be marked on the karabiner body in kN, using defined symbols: major axis with the gate closed, minor axis, and major axis with the gate open. Its illustration shows an HMS karabiner marked 22, 10 and 9 kN. The text singles out the gate-open figure as the most important one for climbers.

Classes H, K and X must carry their letter inside a circle. Classes D, A and Q are recognisable by shape and need no letter, and any karabiner without an H, K or X is a basic connector, which need not be marked B. The BMC text notes that nearly all karabiners made before 1990 carry no gate-open marking at all.

Why gate-open strength is 7 kN

Before the European standard there were two karabiner standards, UIAA and DIN. A UIAA comment (undated) says the UIAA wanted 9 kN gate-open strength while DIN required only 6 kN, which was recognised as too low, and that agreement settled on 7 kN. The BMC text says the 1998 standard raised the minimum from 6 kN to 7 kN to make gate-open failures less likely, but that 7 kN does not guarantee they never happen.

Oval connectors are the exception. The BMC text explains that their shape makes them inherently weaker with the gate open, that the standard allows them as low as 5 kN, and that it is accepted they will not give full protection in a leader fall.

What the BMC's investigations found

The BMC's Equipment Investigation Panel found that most karabiner failures reported to it came from loading with the gate open, and next from abnormal loading that forced the gate open (2001 text). It reported rare manufacturing faults over 20 years, such as a displaced gate spring pusher or a loose hinge or latch pin, and cases of seawater corrosion from lack of care. The same text says forces on the top runner in normal falls held by a dynamic rope are very unlikely to exceed 10 kN, but that with no energy absorption in the system, only karabiners, quickdraws and tape, forces above 25 kN are possible, enough to break a karabiner with its gate closed.

Gate designs

• Solid gates use a solid metal gate with a separate pin and spring, the traditional design used by most locking karabiners (Wikipedia).
• Wire gates use a single bent piece of spring-steel wire and are lighter (Wikipedia). The BMC text says the lower mass greatly reduces the chance of the gate opening through whiplash, but that some wire gates may open more readily when scraped along rough rock under load; it concludes that wire gates solve some problems but not all.
• Locking gates. The BMC text refers to two kinds, screwgates and auto-locking gates, and says both can wear over time and stop working correctly.

Quickdraws

The BMC text describes class D directional connectors as those designed for loading in one direction with a captive or semi-captive sling, as used in quickdraws, and says quickdraws and other connectors with textile parts are best stored cool, dark, dry and airy. The American Alpine Club's monthly series The Prescription (November 2024) reported three accidents in 2023 in which a quickdraw unclipped or snagged on a bolt hanger. Sling standards are covered on the slings and anchors page.

How long a karabiner lasts

The BMC text distributed by the UIAA says a properly looked-after karabiner has no reason not to last at least 20 years, and that karabiners are more often replaced for handling or weight than for strength. DMM, a maker, gives its metal products no time limit in its undated instructions. A climbing website, in an article we could not date, reports DMM and Wild Country as recommending a 10-year maximum for metal parts, which DMM's own instructions contradict. The BMC text lists signs it treats as reasons to discard a karabiner, among them a gate that does not close fully, a cracked or distorted locking sleeve and cracking or an etched surface where there is corrosion. These are statements by the named source; the maker's instructions and a competent person decide whether a particular karabiner stays in use. The gear lifespan page compares them with other makers.