Carabiners
Carabiners come in a variety of shapes, sizes, and strengths and can be used for years if they are not damaged by a serious blow or long fall (hairline fractures can develop in aluminum carabiners after a fall). You’d be surprised how much of a beating a carabiner can take. We’ve seen people with 30-year-old carabiners still looking untouched – though we wouldn’t recommend this. Inspect all carabiners frequently.
Carabiners used in life-support applications shall be of the selfclosing, positive-locking type, (triple action, double auto-locking, three-stage) and along with screw links, shall have a minimum tensile strength of 5,000 pounds (22 kN). Several types of steel and aluminum carabiners meet these requirements. Standard one-quarterturn, twistlock carabiners do not have a positive-locking mechanism and shall not be used in lifesupport applications.
Carabiners sold for climbing must have passed at least one of two sets of safety standards, and show the relevant marks. The first is the EN 12275:2013 rating and a CE marking, with a code for the lab that produced the test. Carabiners can also be certified by the UIAA and show their mark.
The UIAA certifications are based on the CE ones so they should be roughly the same minimum standards, with some extra conditions. Most carabiners are rated to both the UIAA and CE standards, so show both markings. If your carabiner doesn’t have at least one of these, don’t use it for climbing.
The full UIAA specifications for carabiner strength can be viewed here (if you’re into that kind of thing).
The minimum strength for most carabiners rated for climbing is 20kN on the major axis. Carabiner strength is rated in kilonewtons (kN) as it’s a measure of force, not weight. A kilonewton is the equivalent of 225lbs of force. Keep in mind that the weight ratings are NOT the lowest strength that a carabiner broke at in testing, but found using a statistical average. That means even if a carabiner is marked at 21kN of breaking strength – it could fail at a lower load. That being said, the vast majority of carabiners will break at a higher kN value than the minimum printed on the carabiner in normal situations.
If carabiners are loaded incorrectly, they can break at much less force than rated for. Avoid these situations whenever you can. Most of the time we see carabiners break, it’s from the nose hooking on a bolt.
- Cross loaded – When a carabiner is being pulled on its minor axis (from side to side) it is at its weakest. Avoid this by keeping an eye out when you are belaying and climbing, or buy a special belay carabiner that won’t cross-load
- Nose hooking – This happens when you clip just the nose of a carabiner into something, leaving the gate open and the nose snagged. This commonly happens when clipping a quickdraw into a bolt in sport climbing. This is very bad – carabiners will break easily if loaded like this.
- Multi-Directional Loading – Most climbing carabiners are designed to be pulled in two directions, not three or more. Strength is lost when used like this to various degrees. Try to avoid
- Cantilever Loading – This often happens accidentally with quickdraws in bolts. Falls can (and have) resulted in the carabiner breaking.
- Loading Over An Edge – This can happen outdoors on badly placed bolts or with trad gear that should be extended with an extra sling. This can result in just 30% of the rated strength!
Steel carabiners are heavier than aluminum carabiners and will usually have a greater breaking strength. While the extra weight can be a disadvantage when carrying equipment into the tree, the steel carabiner is stronger.
A carabiner with a large gate opening is recommended for any rescue situation. Carabiners shall not be painted or covered with tape (other than a small piece for identification) because the covering may mask fractures or other defects.
Carry plenty of carabiners into the tree or have them available on the ground. When attaching a carabiner, always make sure it is properly attached, it is loaded only through the long axis, and its gate is closed and locked. Never place a load on the gate of a carabiner. Screwlock carabiners can be used only in applications that do not involve life support. When using these carabiners, don’t overtighten the locking mechanism or tighten it when the carabiner is under load; doing so may cause the locking mechanism to jam.
Use compressed air to remove grit and use non-abrasive hand cleaner to remove sap. Thoroughly rinse and dry. Use graphite to lubricate components. Never use oil because it will attract dust.
A minimum of 4, triple-action, double-locking life support style, and at least 2 standard ovals or Ds for gear attachment and other miscellaneous, non-life supporting uses
Screw Links
Like carabiners, screw links are a strong, secure means of attachment and can be used instead of knots. They have a threaded sleeve closure instead of a springloaded hinged gate.
Screw links can withstand multidirectional forces placed on them while carabiners are only designed to be loaded along their long axis.
Consider using screw links when a semipermanent attachment is needed (such as chicken loops) or to attach tie-in points on a chest or seat harness.
Do not overtighten the gate screw. When screw links have been under a heavy load, you often need pliers to loosen the threaded sleeve.
WHEN TO REPLACE CARABINERS & SCREW LINKS
The best way to find out if a carabiner should be replaced is with a visual check. Age comes into play, but the major factors in replacing a carabiner are normally obvious when looking at them closely. If you see any of these signs on a carabiner you should immediately replace it:
- Rust - Any rust on the outside of the carabiner means the inner metal has probably been weakened.
- Burrs or sharp edges where a rope can run through. It’s normal to have small burrs on the bolt side carabiner of quickdraws, but burrs and sharp parts on the carabiner where the rope runs through are bad. Ropes can cut pretty easily when running over a sharp edge on a biner.
- Large Grooves - Where a rope runs over the same areas consistently, a groove forms. When this goes past a millimeter or so, sharp edges form on the side of a groove. These can easily cut a rope in a fall.
- Gate won’t close - A sticky gate can often be cleaned but one that doesn’t snap close should be retired straight away.
- Cracks - Any cracks mean a carabiner should be replaced. Cracks generally form in areas around holes like where the rivet pin is, or near to the edges of the main body like at the nose.
- Bent - If your carabiner has suffered a bend that wasn’t there before, its structure will have been significantly weakened and should not be climbed on again.
- Loose / Damaged Rivet - Any risk of the carabiner not closing is a major problem.
- Missing Parts – Some carabiner gates have a few small parts that help the spring function. If one of these falls out, it could stop closing.
- Sea Water Damage - Anything that looks like “pitting”, or a mottled discoloring of metal means serious damage. Flaking or peeling will eventually occur. These can break with hand strength only.
- Fire Damaged - If one has been in or near a fire, it could look fine but the carabiner strength can be comprised by internal damage. Aluminum and steel don’t need to melt to be massively weakened.
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If a carabiner has been stored or left near certain corrosive chemicals, you should also seriously consider replacing them. Car battery acid from leaving biners on the floor of a car, leaving them near spilled cleaning chemicals, and climbing on the coast near to the sea are three common situations.
What should be ok:
- Falls - Carabiners are designed to be loaded and fallen on. Whether it’s the biner on your cam, quickdraws, or anchor, they can take repeated falls.
- Drops - You don’t need to replace carabiners that are dropped, but it depends on what you think is safe. A drop from a few meters up might be OK, but higher than that introduces the risk of internal fractures. Any visible cracks are serious problems.
- Worn Anodizing - The color of carabiners comes from anodizing, a chemical process that turns the outer of a biner into a form of coating and coloring all in one. This anodized color can wear without any major problems – though opens it up to the elements easier.
- Slight Wear - Some scuffing and wear are OK for carabiner strength.
- Small Groove - A slight groove is the most common thing that climbers will ask about when thinking about replacing a carabiner. It depends on the design of the biner. Most manufacturers recommend replacing when the groove is 1mm or more, which is a good rule of thumb.