Non-locking carabiners are used for primarily for climbing protection. They are not used on anchor systems, except where they are connected to a single anchor which forms a component of an anchor system, and the carabiner as well as the anchor are thereby backed up by other equipment. They are not used in belay systems or in abseiling.
Occasionally snap-links are used on cowstails (particularly in caving), but this use is only safe if there are always two cowstails connected to the anchors. Otherwise a twist-lock carabiner should be used on one cowstail.
Snap-links are also used for carrying gear, and occasionally for other uses such as on re-direction anchors in caving.
Bent-gate snap-links are designed to be easy to clip the rope to. Therefore they are used as the lower carabiner on a quickdraw, and as the carabiner on other protection (camming devices, etc). Care must be taken not to twist quickdraws, as bent-gates are as easy to unclip as they are to clip.
Plain-gate snap-links (straight-gates) are used on slings, protection, and at the top end of a quickdraw. Plain-gates may be used, with care, on anchors, if they are doubled and have the gates opposed.
If quickdraws are used on bolt hangers, the same carabiner should always be at the rope end, because burrs which develop from contact with the hanger could damage the rope.
Generally locking carabiners are used for belaying, abseiling, and anchor attachments. Screw-locks or triple-locks are used for belaying and abseiling. Twist-locks must not be used for abseiling with a figure-8 descender as they can be twisted out of the attachment eye. However they are excellent for cowstails, as they are fast to operate and are secure in this role.
carabiners must not be dropped, as they can develop fine cracks on impact. If they become wet, they should be dried before storage. Any identification markings should be confined to the gate: the body of the carabiner must not be altered.
Keep carabiners away from heat and wash salt water off to avoid corrosion. If they become dirty, wash them in warm water (30-40 degrees).
Very little maintenance is required for carabiners. It may be desirable to lubricate the pin and spring sparingly with a silicone-based spray lubricant occasionally. Any excess must be wiped off, as it will attract dirt, which will finish up on the ropes.
During regular, scheduled inspections the following should be checked:
- The gate mechanism should operate freely
- The gate should close straight so that it cleanly engages the latch pin
- The body of the carabiner should be free of cracks, marks and deep scratches
- There should be no corrosion evident
- The inside top corners of plain-gate carabiners should be checked carefully, as they may develop burrs by contact with bolt hangers
- Locking mechanisms should operate freely
- The sleeves of screw-lock carabiners should remain in the closed position without any free movement
- The tangs on the end of the gate should be examined very closely for fine cracks. Some types of carabiner are prone to cracks there which can seriously weaken the carabiner
The life of carabiners is detailed in the manufactures instructions. If they are treated well, are not damaged, and their moving parts continue to function properly there lifespan can be to the maximum recommended. However, the possibility of invisible corrosion around the pins should be considered.
If any of the defects listed above are found, the carabiner should be retired, unless the defect can be fixed by cleaning or lubrication. Burrs on the inside corner caused by bolt hangers must be removed by filing to avoid damaging ropes. However, the amount of material removed must not exceed 10%, or the carabiner will be significantly weakened and must be retired.
Triple-lock carabiners are prone to failure of the gate mechanisms, and must not be used if they do not close and lock properly.
Any retired carabiners should be destroyed or distinctively marked.